Guiding catheter for the coronary sinus

A guiding catheter for delivery of intravascular devices to a patient's coronary sinus. The guiding catheter has a relatively stiff proximal section and a relatively flexible distal section, the latter being about 1 to about 6 inches in length and being configured to subselect a branch cardiac vein leading to the coronary sinus. The guiding catheter is particularly suitable for delivering an intravascular device for sensing electrical activity into a cardiac vein to detect such activity from within the blood vessel.

BACKGROUND OF THE INVENTION 
This invention generally relates to a guiding catheter for the direction of 
an intravascular device into a patient's coronary sinus and particularly 
to the direction of a mapping device into a cardiac vein draining into the 
coronary sinus for detecting electrical activity or signals causing or 
involved with arrhythmia from within the cardiac vein. 
One of the most frequently used treatment modalities for arrhythmia is to 
destroy or damage heart tissue which causes the arrhythmia or involved 
with the arrhythmia by suitably heating the tissue, e.g. applying a laser 
beam or high frequency electrical energy (RF or microwave). 
To be effective, the location of the tissue site causing or involved with 
the arrhythmia must be accurately determined in order to be able to 
contact a heart surface adjacent to the desired location with a tissue 
device. A major problem of ablating the site of the origin of the signals 
or a conductive pathway with commercially available devices is that an 
excessive amount of good tissue is very frequently damaged or destroyed 
along with the arrhythmogenic site to ensure that the arrhythmia does not 
return. For example, the average arrhythmogenic site consists of about 1.4 
cm.sup.2 of endocardial tissue, whereas a re-entrant site might be much 
larger. RF ablation techniques with commercially available devices produce 
lesions about 0.5 cm.sup.2 in diameter, so that it may be necessary to 
form several overlapping lesions in the region in order to completely 
ablate the area of interest and termination of the arrhythmia. If the 
arrhythmogenic or re-entrant site has not been accurately mapped, much 
good tissue surrounding the site will be unnecessarily damaged or 
destroyed to ensure termination of the arrhythmia. 
A variety of methods have been used to detect electrical activity within a 
patient's heart to facilitate the mapping of electrical activity causing 
the arrhythmia. A number of U.S. Patents describe the use of elongated 
intravascular signal sensing devices which are advanced through the 
patient's vasculature until the distal portions of the sensing devices are 
disposed within a patient's heart chamber with one or more electrodes on 
the distal portion of the sensing device in contact with the endocardial 
lining. While this procedure is widely used, it does not always allow the 
site of arrhythmogenic signals to be accurately determined and frequently 
results in unnecessary damage to heart tissue which may already be in 
jeopardy. 
Copending application Ser. No. 08/188,619, filed Jan. 27, 1994 now U.S. 
Pat. No. 5,509,041 entitled INTRAVASCULAR SENSING DEVICE describes 
intravascular devices which can be advanced into a patient's coronary 
artery or cardiac vein where the device is used to detect electrical 
activity of the patient's heart. 
While there are commercially available guiding catheters suitable for 
directing a variety of intravascular devices into a patient's coronary 
arteries, there are no devices available which allow for the rapid 
advancement of an intravascular device into a patient's coronary sinus and 
particularly into a cardiac vein draining into the coronary sinus. 
SUMMARY OF THE INVENTION 
The present invention is directed to a guiding catheter which is configured 
to be advanced through the patient's peripheral vascular system, through 
the right atrium and into the coronary sinus through the coronary sinus 
ostium. Within the coronary sinus the distal end of the guiding catheter 
is used to subselect and enter a branch vein leading toward the coronary 
sinus. 
The guiding catheter of the invention has a relatively stiff proximal shaft 
section and a relatively flexible distal shaft section which is at least 
in part shaped or is shapeable to a shape suitable for advancement within 
the patient's coronary sinus and particularly a branch vein thereof. The 
distal shaft section preferably has a proximal portion which has a 
flexibility greater than that of the proximal shaft section and a distal 
portion which has a flexibility greater than that of the proximal portion 
of the distal shaft section. An inner lumen extends within the catheter 
shaft to and in fluid communication with a port in the distal end thereof. 
An intermediate shaft section may be disposed between the proximal and 
distal shaft sections and have a flexibility intermediate that of the 
proximal and distal shaft sections. 
The proximal shaft section is preferably formed of polymer material having 
a durometer hardness of about 60D to about 90D (Shore), the intermediate 
section a polymer material having a durometer hardness of about 30D to 
about 60D (Shore) and the distal shaft section of a polymer material 
having a durometer hardness of about 80A to about 20D (Shore). A suitable 
material for the proximal shaft section is Pebax 7233 (available from 
Atochem), a suitable material for the proximal portion of the distal shaft 
section is Pebax 5533 (also available from Atochem) and a suitable 
material for the distal portion of the distal shaft section is Tecothane 
(available from Thermedics, Inc. 
The length of the distal shaft section is about 2 to about 7 cm, preferably 
about 3 to about 6 cm to ensure that the distal end of the catheter shaft 
seats well into the desired vein branching off from the coronary sinus. 
The length of the intermediate shaft section is about 1 to about 8 
centimeters. The overall length of the catheter shaft is about 25 to about 
75 cm. 
In one presently preferred procedure the catheter is introduced into the 
patient's venous system, e.g the femoral vein, by conventional Seldinger 
techniques and advanced through the patient's vasculature into the right 
atrium. The proximal end of the catheter shaft extending out of the 
patient is torqued to guide the distal end of the catheter through the 
coronary sinus ostium into the coronary sinus. With the distal end of the 
catheter within the coronary sinus, the catheter is advanced and further 
torqued to direct its distal end into a desired branch vein which drains 
into the coronary sinus. Alternatively, the catheter can be advanced over 
a guidewire which is slidably disposed at the inner lumen thereof with the 
distal extremity of the guidewire being disposed within the desired 
location within the patient's coronary sinus or branch vein. However, in 
this latter instance the catheter shaft need not be torquable but it must 
have sufficient pushability to be advanced over the guidewire. 
When the guiding catheter of the present invention is properly positioned 
within the patient's coronary sinus with its distal extremity seated 
within the desired branch vein which drains into the coronary sinus, an 
intravascular device having sensing electrodes on the distal extremity 
thereof may be advanced through the inner lumen of the guiding catheter 
into the branch vein. The intravascular device is advanced through the 
branch vein until the sensing electrodes on its distal end are positioned 
at a desired location within a branch vein beyond the distal end of the 
guiding catheter. Electrical activity, such as electrical activity causing 
or involved with arrhythmia, may be detected by the sensing electrodes and 
the activity sensed is converted to signals which are used to develop a 
visual representation of the electrical activity. The position of the 
intravascular device within the blood vessel may be adjusted to more 
accurately determine the source of the electrical activity. Once the 
region of the patient's heart causing or involved with the arrhythmia is 
located, an ablation device may be introduced to ablate the tissue 
involved with or causing the arrhythmia and. thereby terminate the 
arrhythmia. For further details of intravascular devices for detecting 
electrical activity and for ablating or lysing tissue causing or involved 
with the electrical activity, reference is made to copending applications 
Ser. No. 08/188,619, filed on Jan. 27, 1994 now U.S. Pat. No. 5,509,411, 
Ser. No. 08/188,384, filed on Jan. 27, 1994, and Ser. No. 08/188,298, 
filed on Jan. 27, 1994, all of which are incorporated herein in their 
entireties. Preferably, the intravascular sensing device used to detect 
electrical activity also has means to ablate or otherwise lyse the tissue 
causing or involved with the electrical activity. 
In one presently preferred embodiment of the invention, the catheter is 
provided with an inflatable balloon on its distal extremity to stop blood 
flow through the blood vessel in order to minimize misdirection of the 
contrast fluid and the dilution thereof which can interfere with 
fluoroscopic observation of the branch blood vessel. 
These and other advantages of the invention will become more apparent from 
the following detailed description of the invention when taken in 
conjunction with the accompanying exemplary drawings.

DETAILED DESCRIPTION OF THE INVENTION 
As shown in FIGS. 1 and 2 the catheter 10 of the invention generally 
includes an elongated shaft 11, a distal shaft section 12, a proximal 
shaft section 13, an inner lumen 14 and an adapter 15 on the proximal end 
of the shaft 11. A port 16 is provided in the distal end of the catheter 
shaft 11 which is in fluid communication with the inner lumen 14. The 
distal shaft section 12 includes a proximal portion 17 and a distal 
portion 18. 
FIG. 3 illustrates the catheter 10 shown in FIG. 1 disposed within the 
patient's vascular system with the distal section 12 of the catheter 
seated within the patient's coronary sinus ostium 19. In this embodiment, 
the catheter 10 has been introduced from the femoral vein (not shown) and 
advanced through the superior vena cava 20 and into the right atrium 21. 
An alternative embodiment of the invention is depicted in FIGS. 4 and 5. In 
this embodiment, the catheter 30 generally includes an elongated catheter 
shaft 31, a distal shaft section 32, a proximal shaft section 33, an inner 
lumen 34, a multiarm adapter 35 on the proximal end of the shaft 31 and an 
occlusion balloon 36 on the distal extremity of the shaft 31. A port 37 is 
provided in the distal end of the catheter shaft 31 which is in fluid 
communication with the inner lumen 34. The catheter shaft 31 is provided 
with an inflation lumen 40 which extends through the shaft 31 to the 
interior of the balloon 36 to direct inflation fluid therein. The side arm 
41 of adapter 35 facilitates introduction of inflation fluid into the 
inflation lumen 40. The center arm 42 of the adapter 35 allows for the 
introduction of a guidewire or catheter or contrast fluid into the inner 
lumen 34. 
FIG. 7 illustrates the distal extremity of the catheter 30 shown in FIGS. 4 
and 5 disposed within a patient's coronary sinus 50 with the distal tip 51 
thereof seated within a branch vein 52 leading to the coronary sinus and 
an intravascular device 70 for detecting electrical activity of a 
patient's heart extending from the lumen of the guiding catheter into the 
branch vein. As shown in FIG. 7, the intravascular device 70 generally 
includes a plurality of sensing electrodes 71 on the distal extremity of 
the device. The balloon 36 is shown in an inflated condition which 
occludes the passageway of the sinus 50. The balloon 36 may be formed of 
inelastic or elastic polymer materials. A presently preferred balloon, 
which is formed of polyurethane (Pellathane-80 A durometer), is available 
from World Medical of Miami, FL. Typically, the balloon has an l.D. of 
about 7F, and inflated diameter of about 8-13 mm and a length of about 9 
mm. 
An alternative embodiment is shown in FIG. 6 wherein the proximal portion 
of the catheter shaft 60 has braided reinforcement 61 to provide increased 
torquability. This embodiment may also have a first lumen 62 and a second 
inner lumen 63, which correspond to the inner lumens 34 and 40 
respectively of the embodiment shown in FIGS. 4 and 5. 
FIGS. 8-11 illustrate various conventional shapes for the distal extremity 
of the guiding catheter of the invention. The shape shown in FIG. 8 is 
commonly called a Josephson type curve, FIG. 9 represents a Damato type 
curve, FIG. 10 a El Gamal type curve and FIG. 11 a hockey stick type 
curve. The proximal, intermediate and distal shaft sections 13, 64 and 12 
are as indicated. The proximal or distal portions of the distal shaft 
section may be shaped before insertion into the patient's body by heating 
the catheter with a mandrel of the desired shape disposed within the inner 
lumen of the distal extremity so that the distal extremity will keep the 
shape of the mandrel when the catheter is cooled. If desired, control 
lines (not shown) may be incorporated into the wall of the catheter and 
extend out the proximal end of the catheter shaft, whereby when tension is 
applied thereto after the catheter is inserted into the patient, the 
distal extremity of the catheter shaft is deflected or shaped in a desired 
manner. These drawings are provided with reference numbers as in FIGS. 1 
and 2. 
Although individual features of embodiments of the invention may be shown 
in some of the drawings and not in others, those skilled in the art will 
recognize that individual features of one embodiment of the invention can 
be combined with any or all the features of another embodiment. Various 
modifications and improvements may be made to the present invention 
without departing from the scope thereof.