Methods of epicardial ablation for creating a lesion around the pulmonary veins

The invention provides surgical systems and methods for ablating heart tissue within the interior and/or exterior of the heart. A plurality of probes is provided with each probe configured for introduction into the chest for engaging the heart. Each probe includes an elongated shaft having an elongated ablating surface of a predetermined shape. The elongated shaft and the elongated ablating surface of each probe are configured to ablate a portion of the heart. A sealing device affixed to the heart tissue forms a hemostatic seal between the probe and the penetration in the heart to inhibit blood loss therethrough.

BACKGROUND OF THE INVENTION 
It is well documented that atrial fibrillation, either alone or as a 
consequence of other cardiac disease, continues to persist as the most 
common cardiac arrhythmia. According to recent estimates, more than one 
million people in the U.S. suffer from this common arrhythmia, roughly 
0.15% to 1.0% of the population. Moreover, the prevalence of this cardiac 
disease increases with age, affecting nearly 8% to 17% of those over 60 
years of age. 
Although atrial fibrillation may occur alone, this arrhythmia often 
associates with numerous cardiovascular conditions, including congestive 
heart failure, hypertensive cardiovascular disease, myocardial 
infarcation, rheumatic heart disease and stroke. Regardless, three 
separate detrimental sequelae result: (1) a change in the ventricular 
response, including the onset of an irregular ventricular rhythm and an 
increase in ventricular rate; (2) detrimental hemodynamic consequences 
resulting from loss of atroventricular synchrony, decreased ventricular 
filling time, and possible atrioventricular valve regurgitation; and (3) 
an increased likelihood of sustaining a thromboembolic event because of 
loss of effective contraction and atrial stasis of blood in the left 
atrium. 
Atrial arrythmia may be treated using several methods. Pharmacological 
treatment of atrial fibrillation, for example, is initially the preferred 
approach, first to maintain normal sinus rhythm, or secondly to decrease 
the ventricular response rate. While these medications may reduce the risk 
of thrombus collecting in the atrial appendages if the atrial fibrillation 
can be converted to sinus rhythm, this form of treatment is not always 
effective. Patients with continued atrial fibrillation and only 
ventricular rate control continue to suffer from irregular heartbeats and 
from the effects of impaired hemodynamics due to the lack of normal 
sequential atrioventricular contractions, as well as continue to face a 
significant risk of thromboembolism. 
Other forms of treatment include chemical cardioversion to normal sinus 
rhythm, electrical cardioversion, and RF catheter ablation of selected 
areas determined by mapping. In the more recent past, other surgical 
procedures have been developed for atrial fibrillation, including left 
atrial isolation, transvenous catheter or cryosurgical ablation of His 
bundle, and the Corridor procedure, which have effectively eliminated 
irregular ventricular rhythm. However, these procedures have for the most 
part failed to restore normal cardiac hemodynamics, or alleviate the 
patient's vulnerability to thromboembolism because the atria are allowed 
to continue to fibrillate. Accordingly, a more effective surgical 
treatment was required to cure medically refractory atrial fibrillation of 
the heart. 
On the basis of electrophysiologic mapping of the atria and identification 
of macroreentrant circuits, a surgical approach was developed which 
effectively creates an electrical maze in the atrium (i.e., the MAZE 
procedure) and precludes the ability of the atria to fibrillate. Briefly, 
in the procedure commonly referred to as the MAZE III procedure, strategic 
atrial incisions are performed to prevent atrial reentry and allow sinus 
impulses to activate the entire atrial myocardium, thereby preserving 
atrial transport function postoperatively. Since atrial fibrillation is 
characterized by the presence of multiple macroreentrant circuits that are 
fleeting in nature and can occur anywhere in the atria, it is prudent to 
interrupt all of the potential pathways for atrial macroreentrant 
circuits. These circuits, incidentally, have been identified by 
intraoperative mapping both experimentally and clinically in patients. 
Generally, this procedure includes the excision of both atrial appendages, 
and the electrical isolation of the pulmonary veins. Further, 
strategically placed atrial incisions not only interrupt the conduction 
routes of the most common reentrant circuits, but they also direct the 
sinus impulse from the sinoatrial node to the atrioventricular node along 
a specified route. In essence, the entire atrial myocardium, with the 
exception of the atrial appendages and the pulmonary veins, is 
electrically activated by providing for multiple blind alleys off the main 
conduction route between the sinoatrial node to the atrioventricular node. 
Atrial transport function is thus preserved postoperatively, as generally 
set forth in the series of articles: Cox, Schuessler, Boineau, Canavan, 
Cain, Lindsay, Stone, Smith, Corr, Chang, and D'Agostino, Jr., The 
Surgical Treatment of Atrial Fibrillation (pts. 1-4), 101 THORAC 
CARDIOVASC SURG., 402-426, 569-592 (1991). 
While this MAZE III procedure has proven effective in ablating medically 
refractory atrial fibrillation and associated detrimental sequelae, this 
operational procedure is traumatic to the patient since substantial 
incisions are introduced into the interior chambers of the heart. 
Moreover, using current techniques, many of these procedures require a 
gross thoracotomy, usually in the form of a median sternotomy, to gain 
access into the patient's thoracic cavity. A saw or other cutting 
instrument is used to cut the sternum longitudinally, allowing two 
opposing halves of the anterior or ventral portion of the rib cage to be 
spread apart. A large opening into the thoracic cavity is thus created, 
through which the surgical team may directly visualize and operate upon 
the heart for the MAZE III procedure. Such a large opening further enables 
manipulation of surgical instruments and/or removal of excised heart 
tissue since the surgeon can position his or her hands within the thoracic 
cavity in close proximity to the exterior of the heart. The patient is 
then placed on cardiopulmonary bypass to maintain peripheral circulation 
of oxygenated blood. 
Not only is the MAZE III procedure itself traumatic to the patient, but the 
postoperative pain and extensive recovery time due to the conventional 
thoracotomy substantially increase trauma and further extend hospital 
stays. Moreover, such invasive, open-chest procedures significantly 
increase the risk of complications and the pain associated with sternal 
incisions. While heart surgery produces beneficial results for many 
patients, numerous others who might benefit from such surgery are unable 
or unwilling to undergo the trauma and risks of current techniques. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide a surgical 
procedure and system for closed-chest, closed heart ablation of heart 
tissue. 
It is another object of the present invention to provide a surgical 
procedure and system for ablating medically refractory atrial 
fibrillation. 
Yet another object of the present invention is to provide a surgical 
procedure and surgical devices which are capable of strategically ablating 
heart tissue from the interior chambers or external cardiac surfaces 
thereof without substantially disturbing the structural integrity of the 
atria. 
Still another object of the present invention is to enable surgeons to 
ablate medically refractory atrial fibrillation while the heart is still 
beating. 
In accordance with the foregoing objects of the invention, the present 
invention provides surgical systems and methods for ablating heart tissue 
within the interior and/or exterior of the heart. This procedure is 
particularly suitable for surgeries such as the MAZE III procedure 
developed to treat medically refractory atrial fibrillation since the need 
for substantial, elongated, transmural incisions of the heart walls are 
eliminated. Moreover, this technique is preferably performed without 
having to open the chest cavity via a median sternotomy or major 
thoracotomy. The system is configured for being introduced through a small 
intercostal, percutaneous penetration into a body cavity and engaging the 
heart wall through purse-string incisions. As a result, the procedure of 
the present invention reduces potential postoperative complications, 
recovery time and hospital stays. 
A system for transmurally ablating heart tissue is provided including an 
ablating probe having an elongated shaft positionable through the chest 
wall and into a transmural penetration extending through a muscular wall 
of the heart and into a chamber thereof. The shaft includes an elongated 
ablating surface for ablating heart tissue. The system of the present 
invention further includes a sealing device fixable to the heart tissue 
around the transmural penetration for forming a hemostatic seal around the 
probe to inhibit blood loss therethrough. 
A preferred method and device for ablating the heart tissue is with a 
cryosurgical ablation device. Although cryosurgical ablation is a 
preferred method, a number of other ablation methods could be used instead 
of cryoablation. Among these tissue ablation means are Radio Frequency 
(RF), ultrasound, microwave, laser, heat, localized delivery of chemical 
or biological agents and light-activated agents to name a few. 
More specifically, the system of the present invention enables the 
formation of a series of strategically positioned and shaped elongated, 
transmural lesions which cooperate with one another to reconstruct a main 
electrical conduction route between the sinoatrial node to the 
atrioventricular node. Atrial transport function is thus preserved 
postoperatively for the treatment of atrial fibrillation. 
The system includes a plurality of surgical probes each having an elongated 
shaft. Each shaft includes an elongated ablating surface of a 
predetermined shape for contact with at least one specific surface of the 
heart and specifically the interior walls of atria chamber. Such contact 
with the ablating surface for a sufficient period of time causes 
transmural ablation of the wall. Collectively, a series of strategically 
positioned and shaped elongated, transmural lesions are formed which 
cooperate with one another to treat atrial fibrillation. Each transmural 
penetration includes a purse-string suture formed in the heart tissue 
around the respective transmural penetration in a manner forming a 
hemostatic seal between the respective probe and the respective transmural 
penetration to inhibit blood loss therethrough. 
When using a cryosurgical probe, the probe includes a shaft having a 
delivery passageway for delivery of pressurized cryogen therethrough and 
an exhaust passageway for exhaust of expended cryogen. The pressurized 
cryogen is expanded in a boiler chamber thereby cooling the elongated 
ablating surface for cryogenic cooling of the elongated ablating surface. 
The elongated shaft is configured to pass through the chest wall and 
through a penetration in the patient's heart for ablative contact with a 
selected portion of the heart. 
In another aspect of the present invention, a surgical method for ablating 
heart tissue from the interior and/or exterior walls of the heart is 
provided including the steps of forming a penetration through a muscular 
wall of the heart into an interior chamber thereof and positioning an 
elongated ablating device having an elongated ablating surface through the 
penetration. The method further includes the steps of forming a hemostatic 
seal between the device and the heart wall penetration to inhibit blood 
loss through the penetration and contacting the elongated ablating surface 
of the ablating device with a first selected portion of an interior and/or 
exterior surface of the muscular wall for ablation thereof. 
More preferably, a method for ablating medically refractory atrial 
fibrillation of the heart is provided comprising the steps of forming a 
penetration through the heart and into a chamber thereof positioning an 
elongated ablating devices having an elongated ablating surface through 
the penetration and forming a hemostatic seal between the ablating device 
and the penetration to inhibit blood loss therethrough. The present 
invention method further includes the steps of strategically contacting 
the elongated ablating surface of the ablating device with a portion of 
the muscular wall for transmural ablation thereof to form at least one 
elongated transmural lesion and repeating these steps for each remaining 
lesion. Each transmural lesion is formed through contact with the ablating 
surface of one of the plurality of ablating device and the strategically 
positioned elongated transmural lesions cooperate to guide the electrical 
pulse pathway along a predetermined path for the surgical treatment of 
atrial fibrillation. 
The entire procedure is preferably performed through a series of only five 
purse-strings sutures strategically located in the right and left atria, 
and pulmonary vein portions. Generally, multiple lesions can be formed 
through a single purse-string either through the use of assorted uniquely 
shaped ablating devices or through the manipulation of a single ablating 
device. 
It should be understood that while the invention is described in the 
context of thoracoscopic surgery on the heart, the systems and methods 
disclosed herein are equally useful to ablate other types of tissue 
structures and in other types of surgery such as laparoscopy and 
pelviscopy. 
The procedure and system of the present invention have other objects of 
advantages which will be readily apparent from the following description 
of the preferred embodiments.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Attention is now directed to FIGS. 1-3 where a human heart H is illustrated 
incorporating a series of strategically positioned transmural lesions 
throughout the right atrium RA and the left atrium LA formed with the 
heart treatment procedure and system of the present invention. FIG. 1 
represents the desired pattern of lesions created on the right atrium RA, 
including the posterior longitudinal right atrial lesion 50, the tricuspid 
valve annulus lesion valve annulus lesion 51, the pulmonary vein isolation 
lesion vein isolation lesion 52 and the perpendicular lesion 53; while 
FIG. 2 represents a right, anterior perspective view of the heart H 
illustrating right atrium RA including a right atrial anteromedial counter 
lesion 55. The cumulative pattern of lesions reconstruct a main electrical 
conduction route between the sinoatrial node to the atrioventricular node 
to postoperatively preserve atrial transport function. Unlike prior 
surgical treatments, the system and procedure of the present invention, 
generally designated 56 in FIGS. 4 and 5, employ a closed-heart technique 
which eliminates the need for gross multiple elongated incisions of the 
atria to ablate heart tissue in the manner sufficient to preclude 
electrical conduction of reentrant pathways in the atria. 
In accordance with the heart treatment procedure and system of the present 
invention, a set of uniquely-shaped, elongated tip ablation probes 57 
(FIG. 4, to be discussed in detail below) are employed which are formed 
and dimensioned for insertion through at least one of a plurality of heart 
wall penetrations, preferably sealed by means of purse-string sutures 58, 
60, 61, 62 and 63, strategically positioned about the atria of the heart 
H. Once the distal end of the probe is inserted through the desired 
purse-string suture, an elongated ablating surface 65 thereof is 
maneuvered into contact with the selected endocardial surface of an 
interior wall of the atria to create an elongated, transmural lesion. As 
shown in FIGS. 3A and 3B, these individual lesions collectively form a 
pattern of transmurally ablated heart tissue to surgically treat medically 
refractory atrial fibrillation. 
Briefly, FIG. 4 represents a collection or set of probes 57 constructed in 
accordance with the present invention which are employed to preclude 
electrical conduction of reentrant pathways in the atria using 
closed-heart surgical techniques. Collectively, as will be apparent, the 
probes enable the surgical formation of a series of lesions which are 
illustrated in FIGS. 3A and 3B. Each probe (FIGS. 24-28 and 32-35) 
includes an elongated shaft 66 formed to extend through an access port or 
passageway 67 in a retractor 68 (FIG. 5) which is mounted in a 
percutaneous intercostal penetration. The terms "percutaneous intercostal 
penetration" and "intercostal penetration" as used herein refer to a 
penetration, in the form or a cut, incision, hole, retractor, cannula, 
trocar sleeve, or the like, through the chest wall between two adjacent 
ribs wherein the patient's rib cage and sternum remain generally intact. 
These terms are intended to distinguish a gross thoracotomy, such as a 
median sternotomy, wherein the sternum and/or one or more ribs are cut or 
removed from the rib cage. It should be understood that one or more ribs 
may be retracted to widen the intercostal space between adjacent ribs 
without departing from the scope of the invention. 
Proximate the distal end of each probe is an elongated ablating end 70 
having an ablating surface 65 formed to transmurally ablate heart tissue. 
Access to the selected portions of the atria of the heart H are provided 
by the specially shaped shafts 66 and ablating ends 70 which are 
configured to position the elongated ablating surface 65 through the chest 
wall of patient P and through a strategically positioned penetration in 
the muscular wall of the patient's heart H for ablative contact with a 
selected portion of an interior surface of the muscular wall. Subsequent 
contact of the ablating surface 65 with specific selected wall portions of 
the atria enable selected, localized transmural ablation thereof. 
In a preferred embodiment the probes 57 form the lesions by freezing the 
heart tissue. Although freezing is a preferred method of ablating tissue, 
the probe 57 may use any other method such as RF ablation, ultrasound, 
microwave, laser, localized delivery of chemical or biological agents, 
light-activated agents, laser ablation or resistance heating ablation. 
Regarding the localized delivery of chemical or biological agents, the 
device may include an injection device capable of injecting the chemical 
or biological agent onto or into the desired tissue for localized ablation 
thereof. The source of the chemical or biological agent may be stored in a 
reservoir contained in the probe or be stored in an external reservoir 
coupled to the injecting end of the probe. 
When the probe freezes tissue during ablation, an opposite end of the probe 
has a fitting 71 formed for releasable coupling to an end of a delivery 
hose which in turn is coupled to a source (both of which are not shown) of 
cryogenic media. A threaded portion 72 of the fitting is formed for 
removable mounting to the delivery hose and further provides communication 
with the cryogenic media for both delivery to and exhaust from the probe. 
As shown in FIG. 6, each probe includes an elongated shaft 66 sufficiently 
dimensioned and shaped to enable manual manipulation of the ablating end 
70 into contact with the desired heart tissue from outside the thoracic 
cavity. The shaft 66 is preferably tubular-shaped and defines a 
communication passageway 73 extending therethrough which provides both 
delivery and exhaust of the cryogen to and from the ablating end 70. 
Communication passageway 73 extends fully from the fitting 71 (FIG. 4) to 
a closed-end boiler chamber 75 where the cryogen exits the ablating end 
70. Preferably, the tubular shaft 66 includes an outer diameter in the 
range of about 2.0 mm to about 5.0 mm, and most preferably about 4.0 mm; 
while the inner diameter is in the range of about 1.5 mm to about 4.5 mm, 
and most preferably about 3.0 mm. 
Concentrically positioned in the communication passageway 73 of each probe 
is a delivery tube 76 (FIG. 6) which extends from the fitting 71 to 
proximate the boiler chamber 75 for communication therebetween enabling 
delivery and dispersion of the cryogen to the boiler chamber. The proximal 
end of delivery tube 76 is coupled to the cryogen liquid source through a 
conventional fitting for delivery of the cryogen through a delivery 
passageway 77. The outer diameter of delivery tube 76 is dimensioned such 
that an annular exhaust passageway 78 is formed between the outer diameter 
of the delivery tube 76 and the inner diameter of the tubular shaft 66. 
This exhaust passageway 78 provides a port through which the expended 
cryogen exiting the boiler chamber can be exhausted. Preferably, the 
delivery tube 76 includes an outer diameter in the range of about 1.4 mm 
to about 3.0 mm, and most preferably about 2.0 mm; while the inner 
diameter is in the range of about 1.15 mm to about 2.75 mm, and most 
preferably about 1.50 mm. 
The shaft of each probe 56 is specifically formed and shaped to facilitate 
performance of one or more of the particular procedures to be described in 
greater detail below. However, due to the nature of the procedure and the 
slight anatomical differences between patients, each probe may not always 
accommodate a particular patient for the designated procedure. 
Accordingly, it is highly advantageous and desirable to provide an exhaust 
shaft 66 and delivery tube 76 combination which is malleable. This 
material property permits reshaping and bending of the exhaust shaft and 
delivery tube as a unit to reposition the ablating surface for greater 
ablation precision. Moreover, the shaft must be capable of bending and 
reshaping without kinking or collapsing. Such properties are especially 
imperative for the devices employed in the pulmonary vein isolation lesion 
formation which are particularly difficult to access. 
This malleable material, for example, may be provided by certain stainless 
steels, NiTi or a shape memory alloy in its superelastic state such as a 
superelastic alloy. Moreover, the shaft portion, with the exception of the 
ablating surface, may be composed of a polymer material such as plastic 
which of course exhibits favorable thermoplastic deformation 
characteristics. Preferably, however, the exhaust and delivery shafts 66 
and 76 are composed of bright annealed 304 stainless steel. The delivery 
tube 76 may also be composed of NiTi or other superelastic alloy. 
To prevent or substantially reduce contact between the concentric tubes 
during operation, due to resonance or the like, the delivery tube 76 may 
be isolated and separated from contact with the inner walls of the exhaust 
shaft 66 by placing spacers around the delivery tube. These spacers may be 
provided by plastic or other polymer material. Alternatively, the delivery 
tube may be brazed or welded to one side of the inner wall of the exhaust 
shaft 66 along the longitudinal length thereof to resist vibrational 
contact, as illustrated in FIG. 8. 
In accordance with the present invention, the lesions formed by this system 
and procedure are generally elongated in nature. The ablating end 70 is 
thus provided by an elongated ablating surface 65 which extends rearwardly 
from the distal end a distance of at least about seven (7) times to about 
thirty (30) times the outer diameter of the ablating end, which 
incidentally is about the same as the outer diameter of the shaft 66. 
Hence, the length of the ablating surface is at least three (3) cm long, 
more preferably at least four (4) cm long, and most preferably at least 
five (5) cm long. Alternatively, the ablating surface 65 has a length of 
between about three (3) cm to about eight (8) cm. 
In most applications, uniform cryothermic cooling along the full length of 
the ablating surface is imperative for effective operation. This task, 
alone, may be difficult to accomplish due primarily to the relatively 
small internal dimensions of the probe, as well as the generally curved 
nature of the boiler chambers in most of the cryoprobes (FIG. 4). FIG. 6 
represents a typical cross-sectional view of an ablating end 70 of one of 
the probe devices of the present invention in which the ablating surface 
65 is formed to contact the heart tissue for localized, transmural 
ablation thereof. Ablating end 70 therefore is preferably provided by a 
material exhibiting high thermal conductivity properties suitable for 
efficient heat transfer during cryogenic cooling of the tip. Such 
materials preferably include silver, gold and oxygen free copper or the 
like. 
The ablating end 70 is preferably provided by a closed-end, elongated tube 
having an interior wall 80 which defines the boiler chamber 75, and is 
about 1.0 mm to about 1.5 mm thick, and most preferably about 1.25 mm 
thick. This portion is specifically shaped for use in one or more ablation 
procedures and is formed for penetration through the muscular walls of the 
heart. The distal end of exhaust shaft 66 is preferably inserted through 
an opening 81 into the boiler chamber 75 such that the exterior surface 82 
at the tip of the exhaust shaft 66 seatably abuts against the interior 
wall 80 of the ablating end 70 for mounting engagement therebetween. 
Preferably, silver solder or the like may be applied to fixably mount the 
ablating end to the end of the exhaust shaft. Alternatively, the proximal 
end of ablating end 70 can be mounted directly to the distal end of 
exhaust shaft 66 (i.e., in an end-to-end manner) using electron-beam 
welding techniques. In either mounting technique, a hermetic seal must be 
formed to eliminate cryogen leakage. 
Proximate the distal end of delivery tube 76 is a delivery portion 83 which 
extends through the opening 81 and into boiler chamber 75 of the ablating 
end 70. This closed-end delivery portion includes a plurality of 
relatively small diameter apertures 85 which extend through the delivery 
portion 83 into delivery passageway 77 to communicate the pressurized 
cryogen between the delivery passageway and the boiler chamber 75. Using 
the Joule-Thompson effect, the cryogen flows through the delivery 
passageway in the direction of arrow 86 and into the delivery portion 83 
where the cryogen expands through the apertures from about 600-900 psi to 
about 50-200 psi in the boiler chamber. As the cryogen expands, it 
impinges upon the interior wall 80 of the ablating end cooling the 
ablating surface 65. Subsequently, the expended cryogen flows in the 
direction of arrow 87 passing through the exhaust passageway 78 and out 
through the delivery hose. 
The number of apertures required to uniformly cool the ablating end is 
primarily dependent upon the length of the boiler chamber 75, the diameter 
of the apertures, the type of cryogen employed and the pressure of the 
cryogen. Generally, for the preferred cryogen of nitrous oxide (N.sub.2 
O), these delivery apertures 85 are equally spaced-apart at about 5 mm to 
about 12 mm intervals, and extend from the proximal end of the boiler 
chamber to the distal end thereof. The preferred diameters of the 
apertures 85 range from about 0.004 inch to about 0.010 inch. These 
diameters may vary of course. 
For most probes, three to four apertures or sets of apertures spaced-apart 
longitudinally along delivery end portion are sufficient. Only one 
aperture 85 may be required at each longitudinal spaced location along the 
delivery portion 83 (FIG. 8). This one aperture may be strategically 
positioned radially about the delivery portion to direct the stream of 
cryogen onto the portion of the interior wall 80 directly beneath or near 
the predetermined portion of the ablating surface 65 which is to contact 
the heart wall tissue for a particular procedure. Hence, the spaced-apart 
apertures may be strategically positioned to collectively direct the 
cryogen onto particular surfaces of the ablating end to assure maximum 
cooling of those portions. In some instances, however (as shown in FIG. 
7), more than one aperture 85 may be radially positioned about the 
delivery portion 83 at any one longitudinal spaced location, proximate a 
plane extending transversely therethrough, for additional cryogenic 
cooling of the ablating surface. This may be especially important where 
the probe is to be employed in more than one procedure. 
Due to the elongated and curved nature of the ablating surface 65, it is 
difficult to maintain a generally uniform temperature gradient along the 
desired portions of the ablating surface during cryogenic cooling. This 
may be due in part to the pressure decrease in the delivery passageway 77 
of the delivery portion 83 as the cryogen passes therethrough. To 
compensate for this pressure loss as the cryogen passes through the 
delivery portion, the diameters of the apertures 85, 85', 85" etc., may be 
slightly increased from the proximal end of the delivery portion 83 to the 
distal end thereof. Thus, as the cryogen travels through the delivery 
portion 83 of the delivery tube, a more uniform volume of cryogen may be 
distributed throughout the boiler chamber 75 even though the cryogenic 
pressure incrementally decreases from the proximal end of the delivery 
portion 83. 
Moreover, the delivery volume of the cyrogenic cooling also may be 
controlled by varying the number of apertures at particular portions of 
the ablating end i.e., increasing or decreasing the number of apertures at 
a particular location. This directed cooling will have a localized cooling 
effect, and is exemplified in the ablating end 70 of FIG. 4. In this 
embodiment, the increased number of apertures along the inner bight 
portion 88 of delivery portion 83 delivers a more direct and greater 
volume of cryogen against the inner bight portion 88, as compared to the 
outer bight portion 90. 
An insulative coating or tubing 89 is preferably included extending 
circumferentially around portions of the cryoprobe shaft 66 near the 
ablation end 70. This insulative tubing provides an insulatory barrier 
around shaft 66 to prevent inadvertent direct contact between the shaft, 
which will be cooled by the expended cryogen flowing through the exhaust 
passageway 75, and any organs or tissue of the percutaneous penetration. 
The insulative tubing is preferably spaced from the shaft 66 to define an 
air gap between the inner surface of the tubing and the outer surface of 
the shaft. 
The insulative tubing 89 preferably extends around the elongated shaft 66 
from the base of the ablation end 70 to the fitting 71. In some instances, 
however, the tubing may only need to extend from the base of the ablation 
end to a midportion of the elongated shaft. The insulative tubing 89 is 
preferably provided by heat shrink polyolefin tubing, silicone, 
TEFLON.RTM., or the like. 
In the preferred form, as shown in FIG. 7, the transverse, cross-sectional 
dimension of the ablating end 70 is circular-shaped having a substantially 
uniform thickness. However, it will be understood that the ablating 
surface 65 may include a generally flat contact surface 91 formed for 
increased area contact with the heart tissue without requiring a 
substantial increase in the diameter of the ablating surface. As best 
viewed in FIGS. 8A-8C, contact surface 91 may be generally flat or have a 
much larger radius than that of the ablating end. Moreover, the 
spaced-apart apertures 85 are preferably oriented and formed to deliver 
the cryogen into direct impingement with the underside of the contact 
surface 91 of ablating end 70. In this arrangement, the delivery portion 
83 of the delivery tube 76 may be mounted to one side of the interior wall 
80, as set forth above. 
Alternatively, the contact surface can be provided by a blunted edge or the 
like to create a relatively narrow lesion. Although not illustrated, the 
transverse cross-sectional dimension of this embodiment would appear 
teardrop-shaped. 
FIGS. 6A-6D illustrate an embodiment of the probe 57 in which an insulative 
jacket or sleeve 304 is disposed on the probe so as to be movable relative 
thereto. The sleeve 304 has a window or cut-out portion 305 which exposes 
a selected area of the probe 57. FIG. 6A shows the sleeve 304 located 
around the probe shaft, while FIG. 6B shows the sleeve after it has been 
slid over part of the probe ablating surface 65. FIG. 6C shows the sleeve 
304 after it has been slid completely over the ablating surface 65 to a 
position where the window 305 exposes one area of the surface 65 for 
ablating tissue. FIG. 6D shows the sleeve 304 rotated to a different 
position where the window 305 exposes a different area of the surface 65 
for ablating tissue. The sleeve 304 may be slidable and rotatable relative 
to the probe as show in FIGS. 6A-6D. Alternatively, the sleeve 304 may be 
fixed axially with respect to the probe 57 but rotatable relative thereto 
so that the window is able to expose different areas of the ablating 
surface. Further still, the sleeve 304 may be fixed on the probe 57 such 
that only a selected area of ablation surface 65 is exposed through window 
305. The sleeve 304 may be formed of any suitable material, for example, a 
flexible polymer having low thermal conductivity. 
The preferred cryogen employed in the devices of the present invention is 
nitrous oxide (N.sub.2 O) which is normally stored in a compressed gas 
cylinder (not shown). Other cryogenic fluids may be employed which include 
liquid nitrogen or liquified air stored in a Dewar vessel (not shown), 
freon 13, freon 14, freon 22, and normally gaseous hydrocarbons. 
To cool the ablating end of the cryoprobe, cryogen is selectively delivered 
through the delivery passageway 77 of delivery tube 76 into the delivery 
conduit thereof. As the cryogen flows through delivery apertures 85, the 
gas expands into the boiler chamber 75, cooling the ablating surface using 
the well known Joule-Thompson effect. The elongated ablating surface 65 is 
then immediately cooled to a temperature of preferably between about 
-50.degree. C. to about -80.degree. C., when nitrous oxide is employed. 
Direct conductive contact of the cooled, elongated ablating surface 65 
with the selected heart tissue causes cryogenic ablation thereof. 
Subsequently, a localized, elongated, transmural lesion is formed at a 
controlled location which sufficiently prevents or is resistant to 
electrical conduction therethrough. 
To assure preclusion of electrical conduction of reentrant pathways in the 
atria, the lesions must be transmural in nature. Hence, the minimum length 
of time for conductive contact of the ablating surface with the selected 
heart tissue necessary to cause localized, transmural ablation thereof is 
to a large degree a function of the thickness of the heart wall tissue, 
the heat transfer loss due do the convective and conductive properties of 
the blood in fluid contact with the ablating surface, as well as the type 
of cryogen employed and the rate of flow thereof. In most instances, when 
employing nitrous oxide as the cryogen, tissue contact is preferably in 
the range of about 2-4 minutes. 
As mentioned, while the closed-heart surgical system and procedure of the 
present invention may be performed through open-chest surgery, the 
preferred technique is conducted through closed-chest methods. FIGS. 5 and 
9 illustrate system 56 for closed-chest, closed-heart surgery positioned 
in a patient P on an operating table T. The patient is prepared for 
cardiac surgery in the conventional manner, and general anesthesia is 
induced. To surgically access the right atrium, the patient is positioned 
on the patient's left side so that the right lateral side of the chest is 
disposed upward. Preferably, a wedge or block W having a top surface 
angled at approximately 20.degree. to 45.degree. is positioned under the 
right side of the patient's body so that the right side of the patient's 
body is somewhat higher than the left side. It will be understood, 
however, that a similar wedge or block W is positioned under the left side 
of patient P (not shown) when performing the surgical procedure on the 
left atrium In either position, the patient's right arm A or left arm (not 
shown) is allowed to rotate downward to rest on table T, exposing either 
the right lateral side or the left lateral side of the patient's chest. 
Initially one small incision 2-3 cm in length is made between the ribs on 
the right side of the patient P, usually in the third, fourth, or fifth 
intercostal spaces, and most preferably the fourth as shown in FIG. 11A. 
When additional maneuvering space is necessary, the intercostal space 
between the ribs may be widened by spreading of the adjacent ribs. A 
thoracoscopic access device 68 (e.g. a retractor, trocar sleeve or 
cannulae), providing an access port 67, is then positioned in the incision 
to retract away adjacent tissue and protect it from trauma as instruments 
are introduced into the chest cavity. This access device 68 has an outer 
diameter preferably less than 14 mm and an axial passage of a length less 
than about 12 mm. It will be understood to those of ordinary skill in the 
art that additional thoracoscopic trocars or the like may be positioned 
within intercostal spaces in the right lateral chest inferior and superior 
to the retractor 68, as well as in the right anterior (or ventral) portion 
of the chest if necessary. In other instances, instruments may be 
introduced directly through small, percutaneous intercostal incisions in 
the chest. 
Referring again to FIGS. 5 and 9, the retractor 68, such as that described 
in detail in commonly assigned U.S. patent application Ser. No. 08/610,619 
filed Mar. 4, 1996, surgical access to the body cavity of patient P 
through the first intercostal percutaneous penetration 92 in the tissue 
93. Briefly, retractor 68 includes an anchoring frame 95 having a 
passageway 67 therethrough which defines a longitudinal retractor axis. 
The anchoring frame 95 is positionable through the intercostal 
percutaneous penetration 92 into the body cavity. A flexible tensioning 
member 96 is attached to anchoring frame 95 and extendible from the 
anchoring frame out of the body through intercostal penetration 92 to 
deform into a non-circular shape when introduced between two ribs. The 
tensioning member 96 is selectively tensionable to spread the tissue 
radially outward from the longitudinal axis. Hence, it is the tension 
imposed on the flexible tensioning member 96 which effects retraction of 
the tissue, rather than relying on the structural integrity of a tubular 
structure such as a trocar sheath. 
Once the retractor 68 has been positioned and anchored in the patient's 
chest, visualization within the thoracic cavity may be accomplished in any 
of several ways. An endoscope 97 (FIG. 5) of conventional construction is 
positioned through a percutaneous intercostal penetration into the 
patient's chest, usually through the port of the soft tissue retractor 68. 
A video camera 98 is mounted to the proximal end of endoscope 97, and is 
connected to a video monitor 100 for viewing the interior of the thoracic 
cavity. Endoscope 97 is manipulated so as to provide a view of the right 
side of the heart, and particularly, a right side view of the right 
atrium. Usually, an endoscope of the type having an articulated distal end 
such as the Distalcam 360, available from Welch-Allyn of Skameateles 
Falls, N.Y., or a endoscope having a distal end disposed at an angle 
between 30 and 90 will be used, which is commercially available from, for 
example, Olympus Corp., Medical Instruments Division, Lake Success, N.Y. A 
light source (not shown) is also provided on endoscope 97 to illuminate 
the thoracic cavity. 
Further, the surgeon may simply view the chest cavity directly through the 
access port 67 of the retractor 68. Moreover, during the closed heart 
procedure of the present invention, it may be desirable to visualize the 
interior of the heart chambers. In these instances a transesophageal 
echocardiography may be used, wherein an ultrasonic probe is placed in the 
patient's esophagus or stomach to ultrasonically image the interior of the 
heart. A thoracoscopic ultrasonic probe may also be placed through access 
device 68 into the chest cavity and adjacent the exterior of the heart for 
ultrasonically imaging the interior of the heart. 
An endoscope may also be employed having an optically transparent bulb such 
as an inflatable balloon or transparent plastic lens over its distal end 
which is then introduced into the heart. As disclosed in commonly 
assigned, co-pending U.S. patent application Ser. No. 08/425,179, filed 
Apr. 20, 1995, the balloon may be inflated with a transparent inflation 
fluid such as saline to displace blood away from distal end and may be 
positioned against a site such a lesion, allowing the location, shape, and 
size of cryolesion to be visualized. 
As a further visualization alternative, an endoscope may be utilized which 
employs a specialized light filter, so that only those wavelengths of 
light not absorbed by blood are transmitted into the heart. The endoscope 
utilizes a CCD chip designed to receive and react to such light 
wavelengths and transmit the image received to a video monitor. In this 
way, the endoscope can be positioned in the heart through access port 67 
and used to see through blood to observe a region of the heart. A 
visualization system based on such principles is described in U.S. Pat. 
No. 4,786,155, which is incorporated herein by reference. 
Finally, the heart treatment procedure and system of the present invention 
may be performed while the heart remains beating. Hence, the trauma and 
risks associated with cardiopulmonary bypass (CPB) and cardioplegic arrest 
can be avoided. In other instances, however, arresting the heart may be 
advantageous. Should it be desirable to place the patient on 
cardiopulmonary bypass, the patient's right lung is collapsed and the 
patient's heart is arrested. Suitable techniques for arresting cardiac 
function and establishing CPB without a thoracotomy are described in 
commonly-assigned, co-pending U.S. patent application Ser. No. 08/282,192, 
filed Jul. 28, 1994 and U.S. patent application Ser. No. 08/372,741, filed 
Jan. 17, 1995, all of which are incorporated herein by reference. Although 
it is preferred to use the endovascular systems described above, any 
system for arresting a patient's heart and placing the patient on CPB may 
be employed. 
As illustrated in FIG. 10, CPB is established by introducing a venous 
cannula 101 into a femoral vein 102 in patient P to withdraw deoxygenated 
blood therefrom. Venous cannula 101 is connected to a cardiopulmonary 
bypass system 104 which receives the withdrawn blood, oxygenates the 
blood, and returns the oxygenated blood to an arterial return cannula 105 
positioned in a femoral artery 106. 
A pulmonary venting catheter 107 may also be utilized to withdraw blood 
from the pulmonary trunk 108. Pulmonary venting catheter 107 may be 
introduced from the neck through the interior jugular vein 110 and 
superior vena cava 111, or from the groin through femoral vein 102 and 
inferior vena cava 103. An alternative method of venting blood from 
pulmonary trunk 108 is described in U.S. Pat. No. 4,889,137, which is 
incorporated herein by reference. In the technique described therein, an 
endovascular device is positioned from the interior jugular vein in the 
neck through the right atrium, right ventricle, and pulmonary valve into 
the pulmonary artery so as to hold open the tricuspid and pulmonary 
valves. 
For purposes of arresting cardiac function, an aortic occlusion catheter 
113 is positioned in a femoral artery 106 by a percutaneous technique such 
as the Seldinger technique, or through a surgical cut-down. The aortic 
occlusion catheter 113 is advanced, usually over a guidewire (not shown), 
until an occlusion balloon 115 at its distal end is disposed in the 
ascending aorta 116 between the coronary ostia and the brachiocephalic 
artery. Blood may be vented from ascending aorta 116 through a port 120 at 
the distal end of the aortic occlusion catheter 113 in communication with 
an inner lumen in aortic occlusion catheter 113, through which blood may 
flow to the proximal end of the catheter. The blood may then be directed 
to a blood filter/recovery system 121 to remove emboli, and then returned 
to the patient's arterial system via CPB system 104. 
When it is desired to arrest cardiac function, occlusion balloon 115 is 
inflated until it completely occludes ascending aorta 116, blocking blood 
flow therethrough. A cardioplegic fluid such as potassium chloride (KCl) 
is preferably mixed with oxygenated blood from the CPB system and then 
delivered to the myocardium in one or both of two ways. Cardioplegic fluid 
may be delivered in an anterograde manner, retrograde manner, or a 
combination thereof. In the anterograde delivery, the cardioplegic fluid 
is delivered from a cardioplegia pump 122 through an inner lumen in aortic 
occlusion catheter 113 and the port 120 distal to occlusion balloon 115 
into the ascending aorta upstream of occlusion balloon 115. In the 
retrograde delivery, the cardioplegic fluid may be delivered through a 
retroperfusion catheter 123 positioned in the coronary sinus from a 
peripheral vein such as an internal jugular vein in the neck. 
With cardiopulmonary bypass established, cardiac function arrested, and the 
right lung collapsed, the patient is prepared for surgical intervention 
within the heart H. At this point in the procedure, whether cardiac 
function is arrested and the patient is placed on CPB, or the patient's 
heart remains beating, the heart treatment procedure and system of the 
present invention remain substantially similar. The primary difference is 
that when the procedure of the present invention is performed on an 
arrested heart, the blood pressure in the internal chambers of the heart 
is significantly less. Hence, it is not necessary to form a hemostatic 
seal between the device and the heart wall penetration to inhibit blood 
loss through the penetration thereby reducing or eliminating the need for 
purse-string sutures around such penetrations, as will be described below. 
In the preferred embodiment, however, the procedure is conducted while the 
heart is still beating. Accordingly, it is necessary to form a hemostatic 
seal between the ablation device and the penetration. Preferably, 
purse-string sutures 58, 60, 61, 62 and 63 (FIGS. 3A and 3B) are placed in 
the heart walls at strategic or predetermined locations to enable 
introduction of the ablating probes into the heart while maintaining a 
hemostatic seal between the probe and the penetration. 
As best viewed shown in FIG. 11A, in order to gain access to the right 
atrium of the heart, a pericardiotomy is performed using thoracoscopic 
instruments introduced through retractor access port 67. Instruments 
suitable for use in this procedure, including thoracoscopic angled 
scissors 130 and thoracoscopic grasping forceps 131, are described in 
commonly assigned U.S. Pat. No. 5,501,698, issued Mar. 26, 1996, which is 
incorporated herein by reference. 
After incising a T-shaped opening in the pericardium 132 (about 5.0 cm in 
length across and about 4.0 cm in length down, FIG. 11A), the exterior of 
the heart H is sufficiently exposed to allow the closed-chest, 
closed-heart procedure to be performed. To further aid in visualization 
and access to the heart H, the cut pericardial tissue 133 is retracted 
away from the pericardial opening 135 with stay sutures 136 (FIG. 11C) 
extending out of the chest cavity. This technique allows the surgeon to 
raise and lower the cut pericardial wall in a manner which reshapes the 
pericardial opening 135 and retracting the heart H slightly, if necessary, 
to provide maximum access for a specific procedure. 
To install stay suture 136, a curved suture needle 137 attached to one end 
of a suture thread 138 is introduced into the chest cavity through 
passageway 67 with of a thoracoscopic needle driver 140 (FIG. 11B). Once 
the suture needle 137 and thread 138 have been driven through the cut 
pericardial tissue, the suture thread 138 is snared by a suture snare 
device 141. This is accomplished by positioning a hooked end 142 of suture 
snare device 141 through at least one additional percutaneous intercostal 
penetration 143 positioned about the chest to enable penetration into the 
thoracic cavity. In the preferred arrangement, a trocar needle (not shown) 
is employed which not only forms the penetration, but also provides access 
into the thoracic cavity without snaring tissue during removal of the 
snare device. 
Accordingly, both sides of the suture thread 138 are snared and pulled 
through the chest wall for manipulation of the stay suture from outside of 
the body cavity. The ends of the stay suture 136 are coupled to a surgical 
clamp (not shown) for angled manipulation and tension adjusting. While 
only two stay sutures are illustrated, it will be appreciated that more 
stay sutures may be employed as needed to further manipulate the 
pericardial opening. 
Turning now to FIG. 11C, a first 4-0 purse-string suture 58, for example, 
is placed in the heart wall proximate the site at which it is desired to 
initiate the first heart wall penetration 146 (FIG. 11D). Again, this is 
accomplished by using a thoracoscopic needle driver to drive the suture 
needle through the heart wall to form a running stitch in a circular 
pattern approximately 1.0-3.0 mm in diameter. A double-armed suture may 
also be used, wherein the suture thread 145 (about 3 mm to about 10 mm in 
diameter) has needles (not shown) at both ends, allowing each needle to be 
used to form one semi-circular portion of the purse-string. Suture thread 
138 is long enough to allow both ends of the suture to be drawn outside of 
the chest cavity once purse-string suture 58 has been placed. The suture 
needle is then cut from thread 145 using thoracoscopic scissors. 
To tension the purse-string suture 58, the suture threads 145 are pulled 
upon gathering the stitched circular pattern of tissue together before 
commencement of the formation of a penetration through the heart wall 
within the purse-string suture. One or a pair of thoracoscopic cinching 
instruments 147, such as a Rumel tourniquet, may be employed to grasp a 
loop of purse-string suture 58. As best viewed in FIG. 11D, cinching 
instrument 147 comprises a shaft 148 with a slidable hook 150 at its 
distal end thereof for this purpose. Hook 150 may be retracted proximally 
to frictionally retain suture thread 145 against the distal end of shaft 
148. By retracting or withdrawing the cinching instrument 147, the 
purse-string suture 58 is cinched tightly, thereby gathering heart wall 
tissue together to form a hemostatic seal. 
The cinching instrument may be clamped in position to maintain tension on 
suture thread 145. Preferably, however, a slidable tensioning sleeve 151 
(FIG. 11D), commonly referred to as a snugger, may be provided in which 
the suture threads are positioned through a bore extending therethrough. 
The snugger is then slid along the suture thread until it abuts against 
the epicardial surface 152 of the heart wall. The cinching instrument is 
then pulled proximally relative to tensioning sleeve 151 to obtain the 
desired degree of tension on suture thread 145. Tensioning sleeve 151 is 
configured to frictionally couple to suture thread 145 to maintain tension 
on the suture. 
An incision device 153 is introduced through access device 68 into the 
chest cavity for piercing the heart H. A blade 155 positioned on the 
distal end of a manipulating shaft 156 is advanced to pierce the heart 
wall within the bounds of purse-string suture 58. The blade 155 is 
preferably about 5.0 mm in length and about 3.0 mm wide terminating at the 
tip thereof. FIG. 11D illustrates that as the incision device 153 is 
manually moved further into contact with the epicardial surface 152 of the 
heart wall, blade 155 will be caused to pierce therethrough to form a 
penetration of about 1.0-2.0 mm across. 
In the preferred form, the blade 155 is rigidly mounted to shaft 156 for 
direct one-to-one manipulation of the blade. Alternatively, however, the 
incision device may employ a spring loaded mechanism or the like which 
advances the blade forwardly from a retracted position, retracted in a 
protective sleeve of the shaft, to an extended position, extending the 
blade outside of the sleeve and into piercing contact with the tissue. In 
this embodiment, a button or the like may be provided near the proximal 
end of the shaft for operation of the blade between the retracted and 
extended positions. 
To facilitate formation of the penetration by the incision device, a 
thoracoscopic grasping instrument (not shown) may be employed to grasp the 
heart wall near purse-string suture 58 to counter the insertion force of 
blade 155 and incision device 153. As blade 155 penetrates the heart wall, 
incision device 153 is advanced to extend transmurally into the heart 
through the penetration 146 formed in heart wall. 
As above-indicated in FIGS. 3A and 3B, the entire procedure is preferably 
performed through a series of only five purse-strings sutures 58, 60, 61, 
62 and 63, and the corresponding cardiac penetrations 146, 157, 158, 160 
and 161 of which two penetrations 158, 160 are strategically positioned in 
the right atrium RA; one penetration 161 is positioned in the left atrium 
LA; and two penetrations 158, 160 are positioned near the pulmonary vein 
trunk 108. Such small incisions are significantly less traumatic on the 
heart tissue muscle than the elongated transmural incisions of the prior 
MAZE techniques. 
Referring now to FIGS. 3A, 12A-12C and 13, the system and procedure of the 
present invention will be described in detail. Preferably, the first 
series of lesions is formed on the right atrium RA to form a posterior 
longitudinal right atrial lesion 50 and a tricuspid valve annulus lesion 
51. It will be appreciated, however, that the transmural lesions can be 
formed in any order without departing from the true spirit and nature of 
the present invention. 
By strategically placing the first heart wall penetration 146 of first 
purse-string suture 58 at the base of the right atrial appendage RAA where 
the anticipated intersection between the longitudinal right atrial lesion 
50 and the tricuspid valve annulus lesion 51 are to occur (FIG. 12C), 
these two lesions can be formed through a series of three independent 
ablations. As best viewed in FIG. 12A, the upper section segment 162 (half 
of the longitudinal right atrial lesion 50) is formed using a right angle 
probe 163 (FIG. 24) having a first elbow portion 166 positioned between 
the generally straight elongated shaft 66 and the generally straight 
ablating end. The first elbow portion has an arc length of about 
85.degree. to about 95.degree. and a radius of curvature of about 3.2 mm 
to about 6.4 mm. The ablating end 70 is preferably about 2.0 mm to about 
4.0 mm in diameter, and about 2.0 cm to about 6.0 cm in length. In this 
configuration, the ablating surface 65 extends, circumferentially, from a 
distal end 165 thereof to just past an elbow portion 166 of the right 
angle probe 163. 
Initially, the probe ablating end 70 and the shaft 66 of probe 163 is 
introduced into the thoracic cavity through the retractor 68 by 
manipulating a handle (not shown) releasably coupled to fitting 71. To 
facilitate location of the first penetration with the probe, the distal 
end 165 is guided along the shaft 156 of incision device 153 (FIG. 11D) 
until positioned proximate the first penetration 146. Subsequently, the 
blade 155 of incision device is withdrawn from the first penetration 
whereby the distal end of the probe is immediately inserted through the 
first penetration. Not only does this technique facilitate insertion of 
the probe but also minimizes loss of blood through the penetration. 
Once the distal end 165 of the right angle probe 163 has been inserted and 
negotiated through the first penetration, the first purse-string suture 
may require adjustment to ensure the formation of a proper hemostatic seal 
between the penetration and the shaft of the probe. If the loss of blood 
should occur, the purse-string suture can be easily tightened through 
either a Rumel tourniquet or tensioning sleeve 151. 
FIG. 12A best illustrates that the right angle probe 163 is preferably 
inserted through the penetration 146 until an elbow portion 166 thereof 
just passes through the penetration. Although the angular manipulation of 
the end of the right angle probe is limited due to the access provided by 
the retractor, the insertion should be easily accommodated since the heart 
wall tissue of the right atrium is substantially resilient and flexible. 
Again, a thoracoscopic grasping instrument (not shown) may be employed to 
grasp the heart wall near the first purse-string suture 58 to counter the 
insertion force of right angle probe 163 through the first penetration 
146. Once the ablating end is inserted to the desired depth and through 
the assistance of either direct viewing or laparoscopic viewing, the 
elongated ablating end 70 is oriented to position a longitudinal axis 
thereof generally parallel to the right atrioventricular groove. This 
upper section segment 162 of the longitudinal right atrial lesion 50 
extends generally from the first penetration 146 to the orifice of the 
superior vena cava 111. By retracting the probe rearwardly out of the 
passageway of the retractor 68 generally in the direction of arrow 167, 
the ablating surface will be caused to sufficiently contact the right 
atrial endocardium. 
As mentioned above, the probe may use any method to ablate the heart 
tissue. When using a cryogenic ablating system, the cryogen stored in a 
Dewar vessel or pressurized cylinder is selectively released where it 
passes into the boiler chamber 75 of the device 163, thereby cooling the 
probe ablating surface for localized ablation of heart tissue. As 
previously stated, to warrant proper transmural ablation of the interior 
wall of the right atrium, continuous contact of the ablating surface 
therewith should occur for about 2-4 minutes. Visually, however, 
transmural cryosurgical ablation of the tissue is generally represented by 
a localized lightening or discoloration of the epicardial surface 168 of 
the ablated heart tissue which can be directly viewed through the access 
port 67 of access device 68. This method of determining cryoablation of 
the tissue can be used in combination with the timed probe contact 
therewith. As a result, the upper section segment 162 of the longitudinal 
right atrial lesion 50 will be formed. 
Once the desired elongated portion of heart tissue has been ablated, 
caution must be observed before the ablating surface 65 probe can be 
separated from the contacted endocardial surface of the heart tissue. Due 
to the extremely low temperatures of the ablating surface (i.e., about 
-50.degree. to about -80.degree.) and the moistness of the heart tissue, 
cryoadhesion can occur. Accordingly, the probe tip must be properly thawed 
or defrosted to enable safe separation after the tissue has been properly 
ablated. 
For example, after sufficient transmural cryoablation of the heart tissue, 
thawing is commenced by halting the flow of cryogen through the probe and 
maintaining continuous contact between the probe ablating surface and the 
cryoablated tissue. After about 10-20 seconds, and preferably about 15 
seconds, the conductive and convective heat transfer or heat sink effect 
from the surrounding tissue and blood is sufficient to reverse the 
cryoadhesion. Of course, it will be appreciated that such heat transfer is 
more efficient when the procedure is performed on a beating heart as 
opposed to an arrested heart. Alternatively, the system may also be 
provided with a defrost mode which serves to warm the tissue to room 
temperature. This may be accomplished by raising the pressure of the 
cryogen adjacent the ablating surface such that its temperature increases, 
for example, by restricting the exhaust gas flow. 
Furthermore, to facilitate thawing of the exterior surface of the ablated 
tissue, a room temperature or slightly heated liquid may be wetted or 
impinged upon the exterior surface of the ablated area. In the preferred 
embodiment, such liquid may include saline or other non-toxic liquid 
introduced into the thoracic cavity through the retractor passageway 67. 
Generally, multiple lesions can be formed through a single purse-string 
suture either through the use of assorted uniquely shaped ablating devices 
or through the manipulation of a single ablating device. Accordingly, 
while maintaining the hemostatic seal between the probe shaft and the 
penetration, the respective ablating device can be manipulated through the 
respective penetration to strategically contact the corresponding 
elongated ablating surface with another selected portion of the interior 
surface of the muscular wall for transmural ablation thereof. For 
instance, without removing the right angle cryoprobe from the first 
penetration, the ablating surface 65 is rotated approximately 1800 about 
the longitudinal axis to re-position the distal end generally in a 
direction toward the orifice of the inferior vena cava 103. As shown in 
FIG. 12B, such positioning enables the formation of the remaining lower 
section segment 170 of the longitudinal right atrial lesion 50. However, 
since the lower section segment 170 of the lesion is shorter in length 
than that of the upper section segment, the length of the elongated 
ablating surface contacting the interior wall of right atrium must be 
adjusted accordingly. This length adjustment is accomplished by partially 
withdrawing the probe ablating surface 65 from the first penetration 146 
by the appropriate length to ablate the lower section segment 170. Due to 
the substantial flexibility and resiliency of the heart tissue, such 
maneuverability of the probe and manipulation of the tissue is 
permissible. 
Similar to the formation of the upper section segment 162 of the 
longitudinal right atrial lesion 50, the right angle probe 163 is 
retracted rearwardly, generally in the direction of arrow 167, causing the 
ablating surface 65 of the probe to sufficiently contact the endocardium 
of the right atrium. After the cryogen has continuously cooled the 
elongated ablating surface 65 of the probe for about 2-4 minutes, the 
remaining lower section segment of the longitudinal right atrial lesion 50 
will be formed. Thereafter, the probe is defrosted to reverse the effects 
of cryoadhesion. It will be understood that while it is beneficial to 
employ the same right angle probe to perform both the upper and lower 
section segments of the longitudinal right atrial lesion, a second right 
angle probe having an ablating surface shorter in length than that of the 
first right angle probe could easily be employed. 
Utilizing the same first penetration, the tricuspid valve annulus lesion 51 
can be formed employing one of at least two probes. Preferably, the right 
angle probe 163 may again be used by rotating the elongated ablating 
surface 65 about the probe shaft longitudinal axis to reposition the 
distal end trans-pericardially, generally in a direction across the lower 
atrial free wall and toward the tricuspid valve 171 (FIGS. 12C and 13). 
The distal end of the probe ablating surface 65, however, must extend all 
the way to the tricuspid valve annulus 172. Hence, in some instances, due 
to the limited maneuvering space provided through the retractor 
passageway, the formation of the tricuspid valve annulus lesion 51 with 
the right angle probe may be difficult to perform. 
In these instances, a special shaped tricuspid valve annulus probe 173 
(FIGS. 13 and 25) is employed which is formed and dimensioned to enable 
contact of the probe ablating surface 65 with appropriate portion of the 
right atrium interior wall all the way from the first penetration 146 to 
the tricuspid valve annulus 172 to form the tricuspid valve annulus lesion 
51. The ablating end 70 and the shaft 66 of this probe cooperate to form 
one of the straighter probes 57 of the set shown in FIG. 4. 
FIG. 25 best illustrates the tricuspid valve annulus probe 173 which 
includes an elongated shaft 66 having a first elbow portion 166 positioned 
between a generally straight first portion 175 and a generally straight 
second portion 176 having a length of about 2.0 cm to about 6.0 cm. The 
first elbow portion has an arc length of about 20.degree. to about 
40.degree. and a radius of curvature of about 13.0 cm to about 18.0 cm. 
Further, a second elbow portion 177 is positioned between the second 
portion 176 and a third portion 178 of the shaft, angling the third 
portion back toward the longitudinal axis of the first portion 175 of the 
elongated shaft 66. The third portion 178 includes a length of about 2.0 
cm to about 6.0 cm, while the second elbow portion has an arc length of 
about 5.degree. to about 20.degree. and a radius of curvature of about 
15.0 cm to about 20.0 cm. The ablating end 70 is relatively straight and 
is coupled to the distal end of the third portion 178 of the elongated 
shaft 66 in a manner angling the ablating end back away from the 
longitudinal axis and having an arc length of about 5.degree. to about 
20.degree. and a radius of curvature of about 13.0 cm to about 18.0 cm. 
The ablating end 70 is formed to extend from the first penetration and to 
the rim 172 of the tricuspid valve 171 from outside of the body cavity. 
For this probe, the ablating surface 65 is preferably about 2.0 cm to 
about 6.0 cm in length. It will be understood that while the illustrations 
and descriptions of the probes are generally two dimensional, the 
configurations of the shaft and ablating end combinations could be three 
dimensional in nature. 
Using the insertion technique employed by the right angle probe 163 during 
the formation of the longitudinal right atrial lesion 50, upon withdrawal 
of the right angle probe from the first penetration 146, the distal end of 
the tricuspid valve annulus probe 173 is immediately inserted therethrough 
to facilitate alignment and minimize the loss of blood. 
Regardless of what instrument is employed, once the probe ablating surface 
65 is strategically oriented and retracted to contact the endocardial 
surface, the cryogen is selectively released into the boiler chamber to 
subject the desired tissue to localized cryothermia. Due to the nature of 
the transmural ablation near the tricuspid valve annulus, the need for 
dividing all atrial myocardial fibers traversing the ablated portion is 
effectively eliminated. Thus, the application of the nerve hook utilized 
in the prior MAZE procedures is no longer necessary. 
As illustrated in FIG. 13, the distal end of the probe must extend to the 
base of the tricuspid valve annulus 172. This lesion is difficult to 
create since the right atrial free-wall in this region lies beneath the 
atrioventricular groove fat pad (not shown). To facilitate orientation of 
the ablating end of the probe relative the valve annulus and to better 
assure the formation of a lesion which is transmural in nature, an 
alternative tricuspid valve clamping probe 180 (FIG. 26) may be employed 
rather than or in addition to the tricuspid valve annulus probe 173. 
This probe includes a primary shaft 66 and ablating end 70 which are 
cooperatively shaped and dimensioned substantially similar to the 
tricuspid valve annulus probe 173. A clamping device 181 of clamping probe 
180 includes a mounting member 179 providing an engagement slot 182 formed 
for sliding receipt of a pin member 184 coupled to primary shaft 66. This 
arrangement pivotally couples the clamping device 181 to the primary shaft 
66 for selective cooperating movement of a clamping jaw portion 183 of the 
clamping device 181 and the ablating end 70 between a released position, 
separating the clamping jaw portion from the ablating end 70 (phantom 
lines of FIG. 26), and a clamped position, urging the clamping jaw portion 
against the ablating end 70 (solid lines of FIG. 26). 
The clamping jaw portion 183 is shaped and dimensioned substantially 
similar to the corresponding ablating end 70 to enable clamping of the 
heart tissue therebetween when the tricuspid valve clamping probe 180 is 
moved to the clamped position. At the opposite end of the clamping jaw 
portion 183 is a handle portion 185 for manipulation of the jaw portion 
between the released and clamped positions in a pliers-type motion. 
To perform this portion of the procedure using the tricuspid valve clamping 
probe 180, the clamping jaw is moved toward the released position to 
enable the distal end of the ablating end to be negotiated through the 
first penetration 146. Using direct viewing through the retractor or 
visually aided with an endoscope, the ablating end is moved into contact 
with the predetermined portion of the right atrium interior wall all the 
way from the first penetration 146 to the tricuspid valve annulus 172. 
Subsequently, the clamping jaw portion is moved to the clamped position, 
via handle portion 185, to contact the epicardial surface 168 of the heart 
wall opposite the tissue ablated by the probe. This arrangement increases 
the force against the ablating surface 65 to facilitate contact and heat 
transfer. Cryogen is then provided to the boiler chamber to cool the 
ablating surface 65 thereby forming the tricuspid valve annulus lesion 51. 
Once the probe is removed from the first penetration 146, the first 
purse-string suture 58 is further tightened to prevent blood loss. 
The engagement slot 182 of mounting member 179 is formed to permit release 
of the pin member 184 therefrom. Hence, the clamping device 181 can be 
released from primary shaft 66 of the clamping probe 180. This arrangement 
is beneficial during operative use providing the surgeon the option to 
introduce the clamping probe 180 into the thoracic cavity as an assembled 
unit, or to first introduce the ablation end 70 and primary shaft 66, and 
then introduce of the clamping device 181 for assembly within the thoracic 
cavity. 
Turning now to FIG. 14, a second 4-0 purse-string suture 59 is placed in 
the right atrial appendage RAA proximate a lateral midpoint thereof in the 
same manner as above-discussed. This portion of the heart is again 
accessible from the right side of the thoracic cavity through the first 
access device 68. A second penetration 157 is formed central to the second 
purse-string suture wherein blood loss from the second penetration is 
prevented through a second tensioning sleeve 186. Subsequently, the distal 
end of a right angle probe or a right atrium counter lesion probe 187 
(FIGS. 15 and 27), is inserted through second penetration 157 and extended 
into the right atrial appendage chamber. Second purse-string suture 59 may 
then be adjusted through second tensioning sleeve 186, as necessary to 
maintain a hemostatic seal between the penetration and the probe. 
The right atrium counter lesion probe 187 includes an elongated shaft 66 
having a first elbow portion 166 positioned between a relatively straight 
first portion 175 and a generally straight second portion 176, whereby the 
first elbow portion has an arc length of about 85.degree. to about 
95.degree. and a radius of curvature of about 1.9 cm to about 3.2 cm. The 
second portion is preferably about 2.0 cm to about 6.0 cm in length. 
Further, a second elbow portion 177 is positioned between the second 
portion 176 and a generally straight third portion 178 of the shaft which 
is about 2.0 cm to about 6.0 cm in length. The second elbow portion has an 
arc length of about 40.degree. to about 70.degree. and a radius of 
curvature of about 3.2 cm to about 5.7 cm, angling the third portion 178 
back toward the longitudinal axis of the first portion 175 of the 
elongated shaft 66. The ablating end 70 is coupled to the distal end of 
the third portion 178 of the elongated shaft 66, and includes an arc 
length of about 85.degree. to about 95.degree. and a radius of curvature 
of about 6.0 mm to about 19.0 mm to curve the distal end thereof back 
toward the longitudinal axis of the first portion 175 of the shaft 66. 
Thus, this equates to an ablating surface length of preferably about 4.0 
cm to about 8.0 cm in length. 
This configuration enables the ablating end 70 of probe 187 to access the 
right lateral midpoint of the atrial appendage RAA where the second 
penetration 157 is to placed. FIGS. 14 and 15 best illustrate that the 
position of this second penetration 157 is higher up than the first 
penetration, relative the heart, when accessed from the predetermined 
intercostal penetration 92. Upon insertion of the distal end of the probe 
through the second penetration 157, the ablating end 70 is inserted into 
the right atrium chamber to the proper depth. The handle (not shown) of 
the probe 187 is manipulated and oriented from outside the thoracic cavity 
to position the distal end of the ablating surface 65 in a direction 
generally toward the first purse-string suture 58. The probe is retracted 
rearwardly out of the retractor passageway, generally in the direction of 
arrow 167 in FIG. 14, to urge the ablating surface 65 of the probe into 
contact with the endocardial surface of the interior wall of the right 
atrial appendage RAA. As a result, the perpendicular lesion 53 of the 
right atrial appendage is transmurally formed. 
The next lesion to be created is the anteromedial counter lesion 55 which 
is to be formed through the second penetration 157. This lesion is 
positioned just anterior to the apex of the triangle of Koch and the 
membranous portion of the interatrial septum. Without removing the right 
atrium counter lesion probe 187 from the second penetration 157, the 
elongated ablating surface 65 is urged further inwardly through the second 
penetration 157 toward the rear atrial endocardium of the right atrial 
appendage RAA (FIG. 15). Upon contact of the ablating surface 65 with the 
rear atrial wall, the probe 187 is slightly rotated upwardly in the 
direction of arrows 191 in FIG. 15 to exert a slight force against the 
rear endocardial surface. Again, this ensures ablative contact 
therebetween to enable formation of the anteromedial counter surgical 
lesion 55. Subsequently, the probe is properly defrosted and withdrawn 
from the second penetration 157 whereby the second purse-string suture 59 
is cinched tighter to prevent blood loss therefrom. It will be understood 
that since these two lesions are formed through cryothermic techniques, 
the need for atrial retraction and endocardial suturing employed in 
connection with the formation of the transmural incision of the MAZE III 
procedure can be eliminated. 
The next step in the procedure is an atrial septotomy to from an anterior 
limbus of the fossa ovalis lesion 192. The formation of this lesion will 
likely be performed without direct or laparoscopic visual assistance since 
the ablation occurs along internal regions of the interatrial septum wall 
193. Initially, as best illustrated in FIGS. 16-18, two side-by-side 
purse-string sutures 61 and 62 are surgically affixed to an epicardial 
surface 168 proximate the pulmonary trunk 108 using the same techniques 
utilized for the first and second purse-string sutures. The third 
purse-string suture 61 is positioned on one side of the septum wall 193 
for access to the right atrium chamber, while the fourth purse-string 
suture 62 is positioned on the opposite side of the septum wall for access 
to the left atrium chamber. 
FIG. 17 further illustrates that the introduction of thoracoscopic 
instruments and access to the third and fourth purse-strings are 
preferably provided through the retractor 68. After the third and fourth 
tensioning sleeves 195, 196 have been mounted to the respective suture 
threads, an incision device (not shown) is introduced into the thoracic 
cavity to incise the penetrations central to the respective purse-string 
sutures. Due to the angle of the upper heart tissue surface relative the 
retractor 68, the incision device may incorporate an angled end or blade 
for oblique entry through the heart wall tissue in the direction of arrow 
197 to form the third and fourth penetrations 158, 160 (FIG. 18). 
Alternatively, the incision device may include a blade end which is 
capable of selective articulation for pivotal movement of the blade end 
relative the elongated shaft. Use of a thoracoscopic grasping instrument 
facilitates grasping of the epicardium near the pulmonary trunk 108 to 
counter the insertion force of the angled blade during formation of the 
respective penetrations 158, 160. 
To create the lesion across the anterior limbus of the fossa ovalis lesion 
192, a special atrial septum clamping probe 198 (FIGS. 17 and 28) is 
provided having opposed right angled jaw portions 200, 201 formed and 
dimensioned for insertion through the corresponding third and fourth 
penetrations 158, 160 for clamping engagement of the anterior limbus of 
the fossa ovalis therebetween. As illustrated in FIG. 28, the atrial 
septum clamping probe 198 includes a primary clamping member 202 having a 
generally straight, elongated clamping shaft 66 with a first elbow portion 
166 positioned between the clamping shaft 66 and a generally straight 
outer jaw portion 200 (ablating end 70), whereby the first elbow portion 
has an arc length of about 85.degree. to about 95.degree. and a radius of 
curvature of about 3.2 mm to about 6.4 mm. The ablating surface extends 
just beyond elbow portion 166 and is of a length of preferably about 2.0 
cm to about 6.0 cm. 
In accordance with the special atrial septum clamping probe 198 of the 
present invention, an attachment device 203 is coupled to the clamping 
shaft 205 which includes an inner jaw portion 201 formed and dimensioned 
to cooperate with the outer jaw portion 200 (i.e., the elongated ablating 
surface 65) of clamping member 202 for clamping engagement of the 
interatrial septum wall 193 therebetween (FIG. 17). Hence, the inner jaw 
portion and the outer jaw portion move relative to one another between a 
clamped condition (FIG. 17 and in phantom lines in FIG. 28) and an 
unclamped condition (FIG. 14A and in solid lines in FIG. 28). In the 
unclamped condition, the inner jaw portion 201 of the attachment device 
203 is positioned away from the outer jaw portion 200 to permit initial 
insertion of the distal end 165 of the outer jaw portion 200 of the 
clamping probe 198 into the fourth penetration 160, as will be discussed. 
The attachment device 203 is preferably provided by a generally straight, 
elongated attachment shaft 206 having a first elbow portion 207 positioned 
between the attachment shaft 206 and a generally straight inner jaw 
portion 201. FIG. 28 best illustrates that the first elbow portion of 
inner jaw portion 201 has an arc length and radius of curvature 
substantially similar to that of the outer jaw portion 200. Further, the 
length of the inner jaw portion is preferably about 2.0 mm to about 6.0 
mm. 
In the preferred form, the attachment shaft 206 is slidably coupled to the 
clamping shaft 66 through a slidable coupling device 208 enabling sliding 
movement of the inner jaw portion 201 between the clamped and unclamped 
conditions. Preferably, a plurality of coupling devices 208 are provided 
spaced-apart along the attachment shaft 206. Each coupling device includes 
a groove 210 (FIG. 29) formed for a sliding, snap-fit receipt of the 
clamping shaft 66 therein for sliding movement of the attachment device in 
a direction along the longitudinal axis thereof. 
The coupling devices are preferably composed of TEFLON.RTM., plastic, 
polyurethane or the like, which is sufficiently resilient and bendable to 
enable the snap-fit engagement. Further, such materials include sufficient 
lubricating properties to provide slidable bearing support as the clamping 
shaft 66 is slidably received in groove 210 to move inner jaw portion 201 
between the clamped and unclamped conditions. Moreover, the coupling 
device configuration may permit rotational motion of the inner jaw portion 
201 about the attachment shaft longitudinal axis, when moved in the 
unclamped condition. This ability further aids manipulation of the 
clamping probe 198 when introduced through the access device 68 and 
insertion through the corresponding fourth penetration 160. 
In the clamped condition, the inner jaw portion 201 is moved into alignment 
with the outer jaw portion 200 of the clamping member 202 for cooperative 
clamping of the septum wall 193 therebetween. An alignment device 211 is 
preferably provided which is coupled between the clamping member 202 and 
the slidable attachment device 203 to ensure proper alignment relative one 
another while in the clamped condition. This is particularly necessary 
since the inner jaw portion 201 is capable of rotational movement about 
the clamping shaft longitudinal axis, when moved in the unclamped 
condition. In the preferred embodiment, FIG. 30 best illustrates that 
alignment device 211 is provided by a set of spaced-apart rail members 
212, 212' each extending from the outer jaw portion 200 to the clamping 
shaft 66 of the clamping member 202. The rail members 212, 212' cooperate 
to define a slot 213 therebetween which is dimensioned for sliding receipt 
of an elbow portion 207 of the inner jaw portion 201. 
To further facilitate alignment between the inner jaw portion and the outer 
jaw portion, the elbow portion 207 of the inner jaw portion 201 may 
include a rectangular cross-section dimensioned for squared receipt in the 
slot 213 formed between the rail members 212, 212'. Alternatively, 
alignment may be provided by the inclusion of a locking device positioned 
at the handle of the probe, or by indexing detents included on the 
clamping shaft. 
Due to the relatively close spacing and placement of the third and fourth 
purse-string sutures 61, 62 in relation to the heart and the retractor 68, 
substantial precision is required for simultaneous insertion of the jaw 
portion distal ends 165, 215. This problem is further magnified by the 
limited scope of visualization provided by either direct viewing through 
the retractor and/or with the endoscope. Accordingly, the septum clamping 
probe 198 includes staggered length jaw portions which position the distal 
end 165 of the outer jaw portion 200 slightly beyond the distal end 215 of 
the inner jaw portion 201 to facilitate alignment and insertion through 
the penetrations 158, 160. In the preferred form, the right angled 
clamping member 202 is initially introduced through access device 68 for 
positioning of the distal end proximate the fourth purse-string suture 62. 
Upon alignment of the outer jaw distal end 165 with the fourth penetration 
160, the clamping member 202 is manipulated in the direction of arrow 197 
for insertion of the outer jaw portion partially into the left atrium 
chamber. The initial insertion depth of the tip is to be by an amount 
sufficient to retain the outer jaw portion 200 in the fourth penetration, 
while permitting the shorter length inner jaw portion 201 of the 
attachment device to move from the unclamped condition toward the clamped 
condition (FIGS. 18A and 18B). 
It will be understood that the slidable attachment device 203, at this 
moment, will either be unattached to the right angle probe or will be 
prepositioned in the unclamped condition. In the former event, the 
slidable attachment device 203 will be introduced through the access 
device 68 and slidably coupled or snap fit to the clamping shaft 66 of the 
clamping member 202 via coupling devices 208. As the inner jaw portion 201 
is advanced in the direction of arrow 216 toward the clamped condition, 
the attachment shaft 206 is rotated about its longitudinal axis, if 
necessary, until the elbow portion 207 is aligned for receipt in the slot 
213 formed between the spaced-apart rails members 212, 212'. In this 
arrangement, the inner jaw portion 201 will be aligned co-planar with the 
outer jaw portion 200 of the clamping member 202. 
The length of the inner jaw portion 201 is preferably shorter than the 
length of the outer jaw portion 200 of clamping member 202 (preferably by 
about 5 mm). With the distal end 165 of the outer jaw portion 200 
partially penetrating the fourth penetration 160 and the distal end 215 of 
the inner jaw portion 201 aligned with the third penetration 158 (FIG. 
18B), the jaw portions are moved in the direction of arrow 197 to position 
the jaws through the penetrations, on opposite sides of the septum wall 
193, and into the atrial chambers. 
As shown in FIG. 17, the jaw portions 200, 201 are inserted to a desired 
depth whereby the clamping probe can be aligned to pass through the 
anterior limbus of the fossa ovalis. When properly oriented, the jaw 
portions can be moved fully to the clamped position exerting an inwardly 
directed force (arrows 216, 216') toward opposed sides of the interatrial 
septum wall 193. Subsequently, the cryogen is released into the boiler 
chamber of the outer jaw portion of the clamping member thereby cooling 
the ablating surface 65 and subjecting the septal wall to cryothermia. 
Due in part to the substantial thickness of this heart tissue, to secure 
proper transmural ablation of the interior septal wall of the right 
atrium, continuous contact of the ablating surface 65 therewith should 
transpire for at least 3-4 minutes to create the anterior limbus of the 
fossa ovalis ablation. The clamping probe 198 and the septum wall are to 
be properly defrosted and subsequently withdrawn from the third and fourth 
penetrations 158, 160, whereby the third and fourth purse-string sutures 
61, 62 are cinched tighter to prevent blood loss therefrom. 
The length of the outer jaw portion is preferably between about 3 cm to 
about 5 cm, while the length of the inner jaw portion is generally about 5 
mm less than the length of the outer jaw portion. Further, the diameter of 
the inner and outer jaw portions is preferably between about 2-4 mm. The 
determination of the diameter and/or length of the particular jaw portions 
and combinations thereof to be utilized will depend upon the particular 
applications and heart dimensions. 
The clamping arrangement of this probe enables a substantial clamping force 
urged between the two opposed jaw portions for more efficient heat 
conduction. This configuration more effectively ablates the relatively 
thicker septum wall since greater leverage can be attained. Accordingly, 
in the preferred embodiment, only the outer jaw portion 200 (i.e., the 
ablating surface 65) of the clamping member 202 needs to be cooled to be 
effective. It will be appreciated, however, that the attachment device 203 
may include the boiler chamber to cool the inner jaw portion as well for 
ablation of both sides of the septum wall 193. 
In an alternative embodiment of the clamping probe 198, as shown in FIG. 
31, the outer and inner jaw portions 200, 201 may cooperate to provide a 
gap 217 at and between the outer elbow portion 166 and the inner elbow 
portion 207. This gap 217 is formed to accommodate the typically thicker 
tissue juncture 218 where the septum wall 193 intersects the outer atrial 
wall 220. Hence, when the clamping probe 198 is moved to the clamped 
condition, the gap 217 is formed to receive this tissue juncture 218 so 
that a more constant compression force may be applied across the septum 
wall between the opposing jaws. This may be especially problematic when 
the tissue juncture is significantly thicker than the septum wall which, 
due to the disparity in thickness, may not enable the distal ends of the 
respective jaw portions to effectively contact the septum wall for 
transmural ablation thereof. 
While FIG. 31 illustrates that the gap 217 is primarily formed through the 
offset curvature at the elbow portion 207 of inner jaw portion 201, it 
will be understood that the outer jaw portion 200 alone or a combination 
thereof may be employed to form the gap 217. Further, in some instances, 
the clamping probe 198 may be derived from the right angle probe set forth 
above. 
After completion of the above-mentioned series of elongated lesions formed 
through the retractor, the right atrial appendage RAA may be excised along 
the direction of solid line 221 in FIG. 3 and broken line 222 in FIG. 19, 
to be described below. This excision is optional depending upon the 
particular circumstance since the risk of a fatal clot or thromboembolism 
is not as great as compared to left atrial appendage LAA. Should this 
excision be performed, the right atrial appendage RAA will preferably, 
first be sutured closed along broken line 222 using conventional 
thoracoscopic instruments. This closure must be hemostatic to prevent 
blood loss when the right atrial appendage is excised. Once a hemostatic 
seal is attained, the appendage is excised using thoracoscopic scissors or 
an incision device. 
While suturing is the preferred technique for hemostatically sealing the 
right atrial chamber, the right atrial appendage may first be surgically 
closed along broken line 222 using staples. In this procedure, a 
thoracoscopic stapling device would be inserted into the thoracic cavity 
through the retractor passageway 67 for access to the appendage. Moreover, 
the right atrial appendage may be conductively isolated by applying a 
specially designed cryoprobe clamping device (not shown) formed to be 
placed across the base of the appendage to engage the exterior surface 
thereof. This lesion will extend completely around the base along the line 
221, 222 in FIGS. 3 and 19 which corresponds to the right atrial appendage 
excision in the prior surgical procedures. 
The next series of lesions are accessed through the left atrium LA. 
Accordingly, a second access device 223, preferably the retractor 68, 
placed between the ribs on the left side of the patient P, usually in the 
third or fourth intercostal space, and most preferably the third 
intercostal space as shown in FIG. 11A. Again, this percutaneous 
penetration is positioned so that thoracoscopic instruments introduced 
through it may be directed toward the left atrium LA of the heart H. When 
additional maneuvering space is necessary, the intercostal space between 
the ribs may be through spreading of the adjacent ribs, or portions of the 
ribs can be easily removed to widen the percutaneous penetration. Further, 
the right lung will be re-inflated for use, while the left lung will be 
deflated to promote access while surgery is being performed. Other lung 
ventilation techniques may be employed such as high frequency ventilation 
without departing from the true spirit and nature of the present 
invention. 
Subsequently, a pericardiotomy is performed to gain access to the left side 
of the heart H utilizing thoracoscopic instruments introduced through the 
retractor 68. Using the same technique mentioned above, a fifth 4-0 
purse-string suture 63 is then formed in the atrial epicardium of left 
atrial appendage LAA proximate a lateral midpoint thereof. Through a fifth 
penetration 161 formed central to the fifth purse-string suture 63, the 
orifices of the pulmonary veins can be accessed to procure conductive 
isolation from the remainder of the left atrium LA. 
In the preferred embodiment, the pulmonary vein isolation lesion 52 is 
formed using a two or more step process to completely encircle and 
electrically isolate the four pulmonary veins. In the preferred form, a 
four-step technique is employed initially commencing with the use of a 
C-shaped, probe 225. As best viewed in FIGS. 19A and 32, the probe 
includes an elongated shaft 66 and a C-shaped ablating end 70 mounted to 
the distal end of the shaft 66. The C-shaped ablating end 70 is shaped and 
dimensioned such that a distal end of the ablating end curves around and 
terminates in a region proximate the longitudinal axis extending through 
the shaft. The ablating end preferably includes an arc length of about 
120.degree. to about 180.degree., and a radius of the arc between about 
6.0 mm to about 25.0 mm. This equates to an ablating surface length of 
preferably about 3.0 cm to about 6.0 cm. 
With the aid of a thoracoscopic grasping instrument (not shown in FIG. 
19A), the distal end of probe 225 is inserted through fifth penetration 
161 to a position past the semi-circular ablating surface 65. A fifth 
tensioning sleeve 226 may be cinched tighter in the event to prevent blood 
loss therefrom. 
To create the first segment 227 of the pulmonary vein isolation lesion 52, 
the distal end of the all-purpose probe is preferably positioned to 
contact the pulmonary endocardial surface 228 of the left atrium LA about 
3-10 mm superior to the right superior pulmonary vein orifice 230. Through 
the manipulation of the probe handle from outside the body, a bight 
portion 232 of the ablating surface 65 is positioned about 3-10 mm outside 
of and partially encircling the right superior and left superior pulmonary 
vein orifices 230, 231. Once aligned, the ablating surface 65 of the probe 
is urged into ablative contact with the desired pulmonary endocardial 
surface 228 to form about 1/3 of the pulmonary vein isolation lesion 52 
(i.e., the first segment 227). 
Without removing the probe 225 from the fifth penetration 161, the probe 
225 is rotated approximately 180.degree. about the longitudinal axis of 
the probe shaft 66 to reorient the ablating surface 65 to form the second 
segment 233 of the pulmonary vein isolation lesion 52. FIG. 19B best 
illustrates that the bight portion 232 of the probe is positioned on the 
other side of pulmonary trunk to contact the pulmonary endocardium about 
3-10 mm just outside of and partially encircling the right inferior and 
left inferior pulmonary vein orifices 235, 236. To ensure segment 
continuity, the distal end of the probe is positioned to overlap the 
distal of the first segment 227 by at least about 5 mm. Once the probe 
bight portion 232 is aligned to extend around the pulmonary vein orifices, 
the ablating surface 65 thereof is urged into ablative contact with the 
desired pulmonary endocardium to form the second segment 233 of the 
pulmonary vein isolation lesion 52. After ablative contact and subsequent 
probe defrosting, the probe is retracted rearwardly from the fifth 
penetration 161 and removed from the second retractor 68. An articulating 
probe (not shown) may also be employed for this procedure which includes 
an ablating end capable of selected articulation of the ablating surface 
to vary the curvature thereof. In this probe, the articulation of the end 
may be manually or automatically controlled through control devices 
located at the handle portion of the probe. This probe may be particularly 
suitable for use in the formation of the pulmonary vein isolation lesion 
due to the anatomical access difficulties. 
Immediately following removal of the probe 225, a right angle probe is to 
be inserted through the fifth penetration 161 of the left atrial appendage 
LAA, in the manner above discussed, to create a third segment 237 of the 
pulmonary vein isolation lesion 52. The formation of this segment may 
require a different right angle probe, having a shorter length ablating 
surface 65 (about 2.0 cm to about 6.0 cm) than that of the first right 
angle probe 163 utilized in the previous ablative procedures. As shown in 
FIGS. 19C, the ablating surface 65 is oriented just outside the left 
superior pulmonary vein orifice 231 by at least about 5 mm. Again, to 
ensure proper segment continuity, it is important to overlap the distal 
end of the ablating surface 65 with the corresponding end of the lesion 
during the formation of the third segment 237 of the pulmonary vein 
isolation lesion 52. After the probe is manually urged into contact with 
the desired pulmonary endocardial surface 228, cryothermia is induced for 
the designated period to transmurally ablate the third segment 237 of the 
pulmonary vein isolation lesion 52. Subsequently, the right angle probe 
ablating surface 65 is properly defrosted to reverse cryoadhesion and 
enable separation from the tissue. 
Similar to the use of the probe 225, without removing the right angle probe 
from the fifth penetration 161, the probe is rotated approximately 
180.degree. about the longitudinal axis of the probe shaft to position the 
ablating surface 65 just outside the left inferior pulmonary vein orifice 
236 by at least about 5 mm (FIG. 19D). Again, to ensure proper segment 
continuity, it is important to overlap both the distal end and the elbow 
portion of the ablating surface 65 with the corresponding ends of the 
second and third segments 233, 237 during the formation of the fourth 
segment 238 of the pulmonary vein isolation lesion 52. Fiberoptic 
visualization or the like is employed to facilitate proper continuity 
between the segments and placement of the probe. Once the probe is urged 
into contact with the desired left atrium interior surface, cryothermia is 
induced for the designated period to ablate the fourth segment of the 
pulmonary vein isolation lesion 52. After the right angle probe ablating 
surface 65 is properly defrosted, the probe is retracted rearwardly from 
the fifth penetration 161 and removed from the second retractor 68. 
Formation of this last segment (i.e., fourth segment 238) completes the 
reentrant path isolation encircling the pulmonary veins (i.e., the 
pulmonary vein isolation cryolesion 52). It will be appreciated, of 
course, that the order of the segment formation which collectively defines 
the pulmonary vein isolation lesion 52 may vary. It is imperative, 
however, that there be continuity between the four segments. If the 
four-step procedure is performed properly, the opposed ends of the four 
segments should all overlap and interconnect to form one unitary ablation 
transmurally encircling the pulmonary trunk 108. 
In accordance with the system and procedure of the present invention, an 
alternative two-step endocardial procedure may be performed to isolate the 
pulmonary veins. As shown in FIGS. 20A and 33, an S-shaped end probe 240 
is provided having a uniquely shaped, opened-looped ablating surface 65 
formed to substantially extend around or encircle the pulmonary vein 
orifices. The S-shaped probe 240 includes an elongated shaft 66 having a 
substantially straight first portion 175 and a C-shaped second portion 176 
mounted to the distal end of the first portion and terminating at a 
position proximate the longitudinal axis of the first portion 175 of shaft 
66. Mounted to the distal end of the C-shaped second portion 176 is a 
C-shaped ablating end 70 which curves back in the opposite direction such 
that the two C-shaped sections cooperate to form an S-shaped end. This 
unique shape enables the ablating surface 65 of ablating end 70 to have an 
arc length of between about 290.degree. to about 310.degree., with a 
radius of curvature of about 1.2 cm to about 3.0 cm. 
FIG. 33 illustrates that the C-shaped ablating end 70 is shaped and 
dimensioned such that a distal end of the ablating end curves around and 
terminates in a region proximate the longitudinal axis extending through 
the shaft. Consequently, the ablating end 70, having a radius of about 
12.0 mm to about 25.0 mm, can then extend substantially around the 
endocardial surface of the pulmonary vein trunk. This is accomplished by 
providing the C-shaped second portion 176 having a radius of curvature of 
at least bout 5 mm to about 7 mm which enables the unimpeded flow of 
cryogen through the delivery tube of the shaft 66. The elimination or 
substantial reduction of this C-shaped second portion 176 positioned just 
before the C-shaped ablating end 70 would create such an acute angle that 
the flow of cryogen about that angle may be impeded. 
Using thoracoscopic grasping instruments, the distal end of this probe is 
carefully inserted through the fifth purse-string suture penetration 161. 
Due in part to the unique near-circular shape of the ablating surface 65, 
initial insertion through the fifth penetration may be one of the most 
difficult and problematic portions of this procedure. 
As shown in FIG. 20A, after the ablating surface 65 of the probe 240 is 
successfully inserted through the fifth penetration 161, the looped 
ablating surface 65 is aligned and positioned to substantially encircle 
the pulmonary vein orifices. Through manipulation of the probe handle from 
outside the thoracic cavity, the probe ablating surface 65 is urged into 
contact with the pulmonary endocardial surface 228 about 3-10 mm just 
outside of the pulmonary vein orifices. Upon proper alignment and ablative 
contact with the epicardial tissue, a first segment 241 of this technique 
is formed (FIG. 20B) which preferably constitutes at least about 3/4 of 
the pulmonary vein isolation lesion. After proper defrosting, the loop 
probe is removed from the fifth penetration and withdrawn through the 
retractor. 
To complete this alternative two-step procedure, an alternative right angle 
probe, above-mentioned, is inserted through the fifth penetration 161 upon 
removal of the S-shaped probe 240. FIG. 20B illustrates that both the 
distal end and the elbow portion of the probe ablating surface 65 are 
aligned to overlap the corresponding ends of the first segment 241 during 
the formation of a second segment 242 of the pulmonary vein isolation 
lesion 52. This ensures continuity between the two connecting segments. 
It will be understood that other shape probes may be employed to isolate 
the pulmonary trunk. The particular customized shape may depend upon the 
individual anatomical differences of the patient, especially since atrial 
fibrillation patients often have enlarged or distorted atria. 
It may be beneficial to access and perform portions of either the four-step 
procedure or the two-step procedure through the right side of the thoracic 
cavity. In these instances, access may be achieved through the first 
access device 68 and the fourth penetration 160 of the fourth purse-string 
suture 62. Moreover, due to the arduous nature of the formation, placement 
and alignment between these segments composing the endocardial pulmonary 
vein isolation lesion in either the two or four segment procedure, it may 
be necessary to ablate an epicardial lesion 243 in the epicardial surface 
168 encircling the pulmonary veins 108 to ensure effective transmural 
tissue ablation for pulmonary vein isolation. Referring to FIGS. 21 and 
33, an epicardial pulmonary vein loop probe 240, substantially similar to 
the probe employed in the procedure of FIG. 20A, is provided for 
introduction through the passageway of the retractor. This probe 
instrument includes an open-looped ablating surface 65 defining an opening 
245 (FIG. 33) formed for passage of the pulmonary veins 108 therethrough. 
Using thoracoscopic grasping instruments, the probe 240 is situated under 
the pulmonary veins wherein the pulmonary veins 108 are urged through the 
opening 245 in the looped ablating surface. Once the ablating surface 65 
is aligned to contact a pulmonary epicardial surface 168 of the pulmonary 
veins 108 at a position opposite the epicardial pulmonary vein isolation 
lesion 52, cryogenic liquid is introduced into the boiler chamber of the 
loop probe 240 for cryogenic cooling of the ablating surface 65. After 
contact for the designated period (2-4 minutes) and proper probe 
defrosting, the loop probe is separated from the pulmonary trunk and 
retracted rearwardly out of the retractor 68. 
Alternatively, this pulmonary epicardial surface isolation may be performed 
from the right side of the thoracic cavity through the first access device 
68 (not shown). In this alternative method, the open-looped ablating 
surface 65 of the loop probe 240 is positioned behind the superior vena 
cava 111, across the anterior surface of the right pulmonary veins, and 
underneath the inferior vena cava 103. Once properly positioned, the 
epicardial surface 168 of the pulmonary trunk 108 can be ablated. 
Turning now to FIG. 22, formation of the left atrial anteromedial lesion 
246 will be described in detail. This lesion 246 is relatively short 
extending only about 5-7 mm from the anteromedial portion of the left 
atrial appendage LAA to the pulmonary vein isolation lesion 52 proximate a 
central portion between the left superior and inferior pulmonary vein 
orifices 231 236. Due to the position of this lesion and the flexible 
nature of the appendage tissue, any one of a number of probes already 
mentioned, such as the probes illustrated in FIG. 32, the right angle 
probe (FIG. 24) or the pulmonary vein to mitral valve probe (FIG. 34), can 
be employed for this task. Typically, the probe device 247 of FIG. 34 is 
employed which includes an elongated shaft 66 having a first elbow portion 
166 positioned between a relatively straight first portion 175 and a 
generally straight second portion 176. The first elbow portion has an arc 
length of about 45.degree. to about 65.degree. and a radius of curvature 
of about 3.2 cm to about 5.7 cm. Further, a second elbow portion 177 is 
positioned between the second portion 176 and the ablating end 70, angling 
the ablating end back toward the longitudinal axis of the first portion 
175 of the elongated shaft 66. The ablating end 70 preferably includes the 
second elbow portion 177, having an arc length of about 80.degree. to 
about 100.degree., and a radius of curvature of about 6.0 mm to about 1.9 
mm. This translates to an ablating surface of about 2.0 cm to about 6.0 cm 
in length. 
One of the above-mentioned probes will be introduced through the second 
retractor 68 where the distal end of the probe will be inserted through 
the same fifth penetration 161 central to the fifth purse-string suture 
63. Once the selected probe 247, as shown in FIG. 22, is properly aligned, 
the ablating surface 65 is urged into contact with the atrial endocardial 
surface of the left atrial appendage LAA for localized ablation. 
Subsequently, the left atrial anteromedial lesion 246 will be formed. 
Since the left atrial wall at the anteromedial portion thereof is 
exceedingly thin, this transmural ablation could be performed from outside 
the heart H. Hence, upon contact of the ablating surface of a selected 
probe (not shown) with the atrial epicardial surface of the left atrial 
appendage LAA, localized, transmural cryothermia may be applied 
externally/epicardially to form this left atrial anteromedial lesion 246. 
The last lesion to be performed through the fifth penetration 161 is the 
posterior vertical left atrial lesion 248, also known as the coronary 
sinus lesion (FIG. 23), extending from the pulmonary vein isolation lesion 
52 to the annulus 250 of the mitral valve MV. This lesion may be critical 
since improper ablation may enable atrial conduction to continue in either 
direction beneath the pulmonary veins. This may result in a long 
macro-reentrant circuit that propagates around the posterior-inferior left 
atrium, the atrial septum, the anterior-superior left atrium, the lateral 
wall of the left atrium beneath the excised left atrial appendage, and 
back to the posterior inferior left atrium. 
Therefore, it is imperative that the coronary sinus be ablated 
circumferentially and transmurally in the exact plane of the atriotomy or 
lesion. Proper transmural and circumferential ablation near the coronary 
sinus effectively eliminates the need for dividing all atrial myocardial 
fibers traversing the fat pad of the underlying atrioventricular groove. 
In the preferred embodiment, a modified probe 251 (FIG. 35) is employed to 
ablate this critical coronary sinus lesion 248. This probe 251 includes an 
elongated shaft 66 having a first elbow portion 166 positioned between a 
generally straight first portion 175 and a generally straight second 
portion 176. The first elbow portion has an arc length of about 30.degree. 
to about 50.degree. and a radius of curvature of about 1.2 cm to about 3.0 
cm. Mounted at the distal end of the second portion 176 is the ablating 
end which is substantially similar in shape to the ablating end of the 
probe of FIG. 32. The ablating end 70 curves back toward the longitudinal 
axis of the first portion 175 of the elongated shaft 66. 
Again, this interior region of the heart H is accessed through the fifth 
penetration 161, via the second access device 223. The distal end of the 
probe 251, is positioned through the penetration in the same manner as 
previous ablations. The unique curvature of this probe 251 enables 
manipulation of the ablating surface 65 from outside the thoracic cavity 
into proper alignment. FIG. 23 best illustrates that ablating surface 65 
is moved into contact with the endocardial surface of the left atrial wall 
atrium for localized ablation extending from the pulmonary vein isolation 
lesion 52 to the mitral valve annulus 250. Particular care, as mentioned 
above, is taken to assure that this lesion extends through the coronary 
sinus for circumferential electrical isolation thereof. After contact for 
the designated period of 2-4 minutes, the ablating surface 65 of the probe 
is properly defrosting and the probe 251 is retracted rearwardly from the 
fifth penetration 161 for removal from the retractor. Subsequently, the 
fifth penetration 161 is further cinched to prevent blood lose through the 
fifth purse-string suture 63. 
Due to the criticality of the circumferential ablation of the coronary 
sinus during formation of the pulmonary vein to mitral valve annulus 
lesion 248, an epicardial ablation may be performed on a portion of the 
outside heart wall opposite the endocardial ablation of the coronary 
sinus. Thus, the placement of this additional lesion (not shown) must be 
in the same plane as the coronary sinus lesion 248 (i.e., to the mitral 
valve annulus lesion) to assure circumferential ablation of the coronary 
sinus. This is performed by introducing a standard probe through the 
retractor 68, and strategically contacting the epicardial surface at the 
desired location opposite the coronary sinus lesion. 
Upon completion of the above-mentioned series of elongated lesions, the 
left atrial appendage LAA is excised along the direction of broken line 
252 in FIG. 23, similar to that of the prior procedures. This excision is 
considered more imperative than the excision of the right atrial appendage 
RAA since the threat of thromboembolism or clotting would more likely be 
fatal, induce strokes or cause other permanent damage. In the preferred 
form, this excision is performed in the same manner as the excision of the 
right atrial appendage (i.e., through suturing or stapling. After 
hemostatic closure is attained, the left atrial appendage LAA is excised 
using thoracoscopic scissors or an incision device. This left 
appendagectomy will extend completely around the base of the left atrial 
appendage along the solid line 252 in FIG. 3 or the broken line 253 in 
FIG. 23, which corresponds to the left atrial appendage excision in prior 
procedures. 
Alternatively, the probes may be formed and dimensioned for contact with 
the epicardial surface 168 of the heart H. In these instances, no 
purse-string suture may be necessary for elongated transmural ablation. As 
an example, as best viewed in FIG. 36, a right-angle clamp type probe 255 
is provided having an outer clamping portion 256 coupled to and formed to 
cooperate with a right angle probe or inner clamping portion 257 for 
transmural ablation of the heart wall through contact with epicardial 
surface 168 of the heart H. In this embodiment, an outer jaw portion 258 
of outer clamping portion 256 is relatively thin (about 0.5 mm to about 
2.0 mm in diameter) and preferably needle shaped to facilitate piercing of 
the heart wall at puncture 260. At the end of the needle-shaped outer 
clamping portion 256 is a pointed end 261 which enables piercing of the 
heart wall without requiring an initial incision and subsequent 
purse-string suture to prevent blood loss through the puncture 260. 
Similar to clamping probe 198, when properly positioned, the outer and 
inner jaw portions 258, 262 of inner clamping portion 257 are moved 
inwardly in the direction of arrows 216, 216' (the outer jaw portion 258 
contacting endocardial surface 228, and the inner jaw portion 262 
contacting epicardial surface 168) to clamp the heart wall therebetween. 
FIG. 36 illustrates that inner jaw portion 262 includes ablation end 70 
having ablation surface 65 which contacts epicardial surface 168 for 
ablation. Upon withdrawal of the needle-shaped outer jaw portion 258 from 
the heart wall, the puncture 260 may be closed through a single suture 
(not shown). 
In these embodiments, an alignment device 263 is provided which cooperates 
between the outer and inner clamping portions 256, 257 for operating 
alignment between the outer jaw portion 258 and the inner jaw portion 262. 
This alignment device may be provided by any conventional alignment 
mechanism such as those alignment devices employed in the clamping probe 
198. 
To ensure transmural ablation, the needle-shaped outer jaw portion 258 may 
incorporate a temperature sensor 265 (FIG. 36) embedded in or positioned 
on the outer jaw portion to measure the temperature of the endocardial 
surface. Measurement of the proper surface temperature will better ensure 
transmural ablation. These temperature sensors may be provided by a 
variety of conventional temperature sensors. 
Referring to FIGS. 37-40, another probe 280 is shown. A cryogen delivery 
tube 282 is positioned within an outer tube 284. A tip 286 seals an end of 
the outer tube 284. The delivery tube 282 is coupled to the source of 
cryogen (not shown) for delivering the cryogen to a boiler chamber 288. 
The cryogen is exhausted from the boiler chamber 288 through the annular 
area between the delivery tube 282 and outer tube 284. The delivery tube 
282 has an end cap 290 which receives first and second tubes 292, 294 for 
delivery of cryogen to the boiler chamber 288 from the delivery tube 282. 
The first tube 292 has an exhaust port 296 which extends further into the 
boiler chamber 288 than an exhaust port 298 of the second tube 294 so that 
the cryogen is distributed throughout the boiler chamber 288. Although 
FIG. 38 depicts only the first and second outlet tubes 292, 294, any 
number of tubes may be provided. 
Ablating surface 300 of the outer tube 284 is preferably made of a highly 
thermally conductive material such as copper. Referring to the end view of 
FIG. 40, the ablating surface 300 preferably has a ribbed inner surface 
302 for enhanced thermal conduction between the boiler chamber 288 and the 
ablating surface 300. The probe 280 may take any of the configurations 
described herein. 
Referring to FIGS. 41 and 42, another probe 306 is shown which has a device 
for adjusting the delivery rate of cryogen. The delivery tube 308 includes 
an inner tube 310 and an outer tube 312. The inner and outer tubes 310, 
312 have holes 314, 316 therein through which the cryogen is delivered to 
boiler chamber 318. The outer tube 312 is slidable relative to the inner 
tube 3 10 and can be locked relative to the inner tube 310 at a number of 
discrete positions where the holes 314 in the inner tube 310 are aligned 
with the holes 316 in the outer tube 312. The holes 314 in the inner tube 
310 are larger than holes 316 in the outer tube 312 so that when the outer 
tube 312 is in the position of FIG. 41 a larger amount of cyrogen is 
delivered than when the outer tube 312 is in the position of FIG. 42. 
Thus, the amount of cyrogen delivered, and therefore the rate of ablation 
and temperature of the probe 306, can be changed by moving the outer tube 
312 relative to the inner tube 310. The delivery tube 308 may be used in 
the manner described above with any of the probe configurations described 
herein. 
Referring to FIGS. 43 and 44, still another probe 318 is shown which 
includes suction ports 320 for ensuring intimate contact between the 
ablating surface 322 and the tissue. The suction ports 320 are coupled to 
a longitudinal channel 324 which is coupled to a vacuum source for 
applying suction. A cryogen delivery tube 326 delivers cryogen to boiler 
chamber 328 in the manner described herein. 
Referring to FIGS. 45-47, a probe 330 having a malleable shaft 332 is 
shown. A malleable metal rod 334 is coextruded with a polymer 336 to form 
the shaft 332. A tip 338 having a boiler chamber 340 is attached to the 
shaft 332. The rod 334 permits the user to shape the shaft 332 as 
necessary so that the tip 338 can reach the tissue to be ablated. The tip 
338 has fittings 342 which are received in a cryogen exhaust path 344 and 
a cryogen delivery path 346 in the shaft 332. The rod 334 is preferably 
made of stainless steel and the polymer 336 is preferably polyurethane. 
The tip 338 may be made of a suitable thermally conductive material such 
as copper. Cryogen is delivered through ports 348 in a delivery tube 350 
and is expanded in the boiler chamber 340. The cryogen is then withdrawn 
through the exhaust path 344. 
Finally, as set forth in the parent application incorporated herein by 
reference, access devices may be placed in the heart walls to enable the 
passage of the probes through the wells of the access devices. 
While the present invention has been primarily directed toward ablation 
from the endocardial surfaces of the atria, it will be understood that 
many lesions or portions of the lesions may be created through ablation of 
the endocardial surfaces of the atria employing the present probes. While 
the specific embodiments of the invention described herein will refer to a 
closed-chest surgical procedure and system for the treatment of medically 
refractory atrial fibrillation, it is understood that the invention will 
be useful in ablation of other tissue structures, including surgical 
treatment of Wolfe-Parkinson-White (WPW) Syndrome, ventricular 
fibrillation, congestive heart failure and other procedures in which 
interventional devices are introduced into the interior of the heart, 
coronary arteries, or great vessels. The present invention facilitates the 
performance of such procedures through percutaneous penetrations within 
intercostal spaces, eliminating the need for a median sternotomy or other 
form of gross thoracotomy. However, as will be apparent although not 
preferred, the system and procedure of the present invention could be 
performed in an open-chest surgical procedure as well.