Abstract:
A pair of cooperating catheters are used together to provide rapid access to the Left heart for diagnostic or therapeutic interventions. The initial entry point for the catheter pair is the groin. The pair of catheters can be used to carry out an electrographic determination of the location of the Fossa Ovalis on the septum. Features on the Catheter system permit quick and reliable confirmation of the catheter location via echo or x-rays. Once across the septum the inner catheter is removed from the outer catheter and a standard intervention may be carried out through the lumen of the outer catheter.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    The present application is a Continuation-in-Part of U.S. patent application Ser. No. 14/715,788, filed on May 19, 2015, entitled Catheter System for Left Heart Access. The present application claims the benefit of, and incorporates herein the entire content of U.S. patent application Ser. No. 14/715,788 by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Many patients undergo diagnostic or interventional procedures in their left heart. For example, a patient with atrial fibrillation may undergo an electrophysiological study inside the chambers of the left heart to determine the physical location of the source of the arrhythmia. This may require the use of electrophysiology (EP) catheters positioned in side the left heart and in contact with the walls of the heart to make electrical measurements to determine the location and propagation properties of the arrhythmia. In some instances, a particular location may be an anatomic defect that can be ablated by yet another catheter system. In a similar fashion a patient may undergo left heart catheterization to receive a Left Atrial Appendage (LAA) Occlusion device that is placed in the LAA. 
         [0003]    Although these procedures are becoming routine there is a need to improve the devices that allow the physician to gain access to the left heart from the right side of the heart and the venous system. The present standard of care involves the use of a stiff straight catheter to reach the right atrium (RA) from an entry site in the leg near the groin. Typically, the venous system is accessed in the groin via the familiar Seldinger procedure. With the conventional catheter placed in the RA a supplemental and exposed needle is advanced out of the conventional catheter and it is used to approach and pierce the septal wall dividing the right heart from the left heart. 
         [0004]    This technique is cumbersome, requires a substantial amount of fluoroscopic exposure to both the patent and the physician and is potentially dangerous of several reasons. 
         [0005]    The inventive devices, systems and methods of the present disclosure provide distinct improvements over the known techniques, in terms of ease of use, safety, and efficiency. 
       SUMMARY OF THE INVENTION 
       [0006]    Devices and systems of the present disclosure include a first (or inner) catheter assembly and two different outer catheter assemblies. The inner catheter may be used with either of the two outer catheters and these two assemblies combined form a system for finding and crossing the fossa ovalis treating a patient according to the methods described herein. 
         [0007]    The first or inner catheter assembly can be used with conventional catheters as well but is less effective and more cumbersome to use in that configuration. 
         [0008]    The paired catheter systems are useful for carrying out a method of finding and crossing the fossa ovalis between the right and left atriums of the heart. 
         [0009]    In the various configurations described herein, the first catheter assembly is coupled to one of the second or third catheter assemblies and form a cooperative system for carrying out steps in an electrographic location procedure. The first catheter assembly is supported by its companion outer catheter (second or third catheter assembly) and together they are used to electrically probe the septal wall surface to determine electrographically the location of the fossa ovalis (FO). The first catheter assembly includes an echogenic piercing tip that may be deployed to extends from the distal tip for piecing the FO. The distal tip is sufficiently opaque to x-rays to be seen radiographically and reflective enough to be visualized using ultrasound. 
         [0010]    Therefore, in use the outer catheter assembly (in the form of either the second catheter assembly or third catheter assembly) supports and places the distal tip of the first catheter assembly at the wall of the septum. The first catheter carries an electrode that is electrically exteriorized to the proximal end of the first catheter. A electrical connection is available on the proximal end of the catheter that may be connected to a standard electromyography (EMG) recoding machine in a unipolar configuration. With the electrode tip within the outer sheath it can still pick up signals from the distal end of the catheter combination and the electrical activity may be observed as the assembly is tracked on the interior wall or septum of the heart. By dragging the distal end region of the system down the septal wall, the FO is characterized by the nature of the electromyography waveform signal. The magnitude and shape of the waveforms are distinct along the septum. When the His bundle signal is diminished that indicates the ideal location for crossing into the left heart. It is important to note that this procedure is carried out with the electrically conductive needle retracted, although the touching of the heart with the blunt catheter tip does cause the EMG to show a so called injury current. 
         [0011]    With the specific FO location identified electrographically, and verified with another and different modality such a X-ray fluoroscopy, the first catheter assembly may be used cross the septum with a deployable needle, which also is extended from the distal tip. Once across the septum the second catheter assembly or third catheter assembly may be advanced into the left heart and used to approach the walls of the left atrium. When a desirable location is reached the first catheter assembly is uncoupled from the outer catheter assembly and the first catheter assembly is withdrawn. 
         [0012]    With the desired treatment location found the first catheter assembly remains stationary and the septum is punctured with the same device via extension of the needle. Although complex electrically and electrographically, the system and method described is quicker and more accurate than the conventional blind probing that is the current state of the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1 a -1 d    are several external views of a first catheter assembly. 
           [0014]      FIG. 2 a    is a longitudinal section view of the catheter assembly shown in  FIGS. 1 a -1 d    wherein a thumb slide and an electrode/needle distal assembly is shown in the retracted state. 
           [0015]      FIG. 2 b    is a longitudinal section view of the catheter assembly of  FIG. 2 a   . wherein the thumb slide and the electrode/needle distal assembly is shown in the extended state. 
           [0016]      FIG. 2 c    is a side view of the embodiment shown in  FIGS. 2 a -2 b   , wherein the assembly is shown connected to a connection lead and an EMG recording system/display. 
           [0017]      FIG. 3 a    is a longitudinal section, detailed view of the distal end region of the catheter assembly shown in  FIGS. 1 a -1 d    with a guidewire extending therethrough and the electrode/needle distal assembly shown in the retracted state. 
           [0018]      FIG. 3 b    is a longitudinal section, detailed view of the distal end region of the catheter assembly shown in  FIG. 3 a    wherein the guidewire is shown extending therethrough, and with the electrode/needle distal assembly shown in the extended state. 
           [0019]      FIG. 3 c    is a longitudinal section, detailed view of the distal end region of the catheter assembly shown in  FIG. 3 d    with the guidewire removed and the electrode/needle distal assembly shown in detail and in the extended state. 
           [0020]      FIG. 4  is a cross-sectional view of the distal end region of the catheter assembly shown in  FIGS. 1-3   c.    
           [0021]      FIG. 5 a    is a rear perspective view of the first catheter assembly engaged to a second catheter assembly. 
           [0022]      FIG. 5 b    is a rear perspective view of the first catheter assembly and second catheter assembly shown in  FIG. 5 a   , but shown prior to their engagement so as to illustrate their proper alignment for engagement. 
           [0023]      FIG. 5 c    is a rear perspective view of the first catheter assembly and second catheter assembly shown in  FIGS. 5 a  and 5 b   , wherein improper alignment for engagement is illustrated. 
           [0024]      FIG. 5 d    is a detailed perspective view showing the proper alignment and function of the engagement mechanisms of the first catheter assembly and second catheter assembly shown in  FIGS. 5 a    and  5   b.    
           [0025]      FIG. 6  is a detailed longitudinal section view of the proximal regions of the first catheter assembly and second catheter assembly shown in  FIG. 5   a.    
           [0026]      FIGS. 7 a -7 e    are several external views of the second catheter assembly shown in  FIGS. 5 a   - 6 . 
           [0027]      FIG. 8  is a longitudinal section view of the proximal region of the second catheter assembly (such as is also shown in  FIG. 6 , but it is shown here without the first catheter assembly engaged thereto). 
           [0028]      FIGS. 9 a -9 e    are several external views of a third catheter assembly. 
           [0029]      FIG. 10 a    is a rear perspective view of the first catheter assembly engaged to the third catheter assembly. 
           [0030]      FIG. 10 b    is a rear perspective view of the first catheter assembly and third catheter assembly shown in  FIG. 10 a   , but shown prior to their engagement, so as to illustrate their proper alignment for engagement. 
           [0031]      FIG. 10 c    is a rear perspective view of the first catheter assembly and third catheter assembly shown in  FIGS. 10 a  and 10 b   , wherein improper alignment for engagement is illustrated. 
           [0032]      FIG. 11 a    is detailed top down view of the handle of the third catheter assembly with the control knob activation button shown in an unactuated or un-pressed state. 
           [0033]      FIG. 11 b    is detailed top down view of the handle of the third catheter assembly with the control knob actuation button shown in an actuated or pressed state. 
           [0034]      FIG. 11 c    is a sectional view of the handle of the third catheter assembly with the control knob in a neutral or un actuated state. 
           [0035]      FIG. 11 d    is a sectional view of the handle of the third catheter assembly with the control knob shown in a rotated state. 
           [0036]      FIG. 12 a   . is a top down view of the third catheter assembly shown in a neutral state. 
           [0037]      FIG. 12 b   . is a longitudinal section view of the third catheter assembly shown in  FIG. 12   a.    
           [0038]      FIG. 12 c   . is a top down view of the third catheter assembly shown in a fully actuated state wherein the control knob is turned to fully actuate the distal end region of the assembly whereby it is turned 180 degrees back on itself. 
           [0039]      FIG. 12 d   . is a longitudinal section view of the third catheter assembly shown in  FIG. 12   c.    
           [0040]      FIG. 13  is a detailed view of the distal end region of the third catheter assembly showing the manner and degree of its possible articulation relative to a neutral position, such as is shown in  FIGS. 12 a   - 12   d.    
           [0041]      FIG. 14  shows an embodiment of the invention in use during a procedure wherein the distal end region of the first catheter assembly extends past the distal end region of the third catheter assembly during initial insertion of the system into a patient&#39;s heart. 
           [0042]      FIG. 15  shows an embodiment of the invention in use during a surgical procedure wherein the distal end region of the first catheter assembly is manipulated and drawn along the superior vena cava so as to align the electrode/needle distal assembly with the fossa ovalis. 
           [0043]      FIG. 16  shows a representative electro-gram typically registered when the distal end region of the first catheter assembly is in the position shown in  FIG. 15 . 
           [0044]      FIG. 17  shows the distal end region of the first catheter assembly properly positioned adjacent to the fossa ovalis during the procedure depicted in  FIG. 15 . 
           [0045]      FIG. 18  shows a representative electro-gram typically registered when the distal end region of the first catheter assembly is in the position shown in  FIG. 17 . 
           [0046]      FIG. 19  represents a real time recording of the electrical activity (via electromyography) detected when the system is in the position shown in  FIG. 17 . 
           [0047]      FIGS. 20 and 21  show the time domain representative of the exploratory motions of the distal end region of the first catheter assembly shown in  FIGS. 15 and 17 . 
           [0048]      FIG. 22  shows characteristic electro grams associated with different regions of the left atrium detected by the electrode/needle distal assembly of the first catheter assembly when immediately adjacent to the respectively depicted regions. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Inner Catheter or First Catheter Assembly 
       [0049]    Turning to  FIGS. 1 a -1 d    a first catheter assembly generally designated  100  is shown. At a proximal end region  102  there is user interface handle  104 . A thumb operated slide  106  is carried in the handle  104  and adapted for sliding motion along the axis  108  of the first catheter assembly. The thumb slide  106  is mechanically engaged to an electrode/needle assembly  125  that is shown in  FIGS. 2 b  and 3 a -3 c    and contained within the distal end region  114  of the first catheter assembly  100  when the thumb slide  106  is in the unactuated state shown in  FIGS. 1 a -1 d  and 2 a   , for example. 
         [0050]    As is best shown in  FIGS. 2 a  and 2 b   , in operation, the thumb slide  106  forces a tang  110  to compress a spring  112  located along and concentric with the axis  108 . Motion of the thumb slide  106  toward the distal end region  114  of the first catheter assembly  100  causes the electrode/needle assembly  125  ( FIG. 2 b   ) to emerge from the distal tip  116  of the distal end region casing (or housing)  118 , as seen in  FIG. 2 a    and  FIG. 2 b    respectively. The mechanical interface between the electrode/needle assembly  125  and the tang  110  may be a wire, shaft, hypo-tube or other elongate member which extends distally from the handle  104 , through the casing  118 . 
         [0051]    As may be seen in  FIGS. 3 a -3 c   , the distal assembly or distal end region  114  has several important features. A hypo-tube  122  has series of laser-machined partially circumferential slits or openings, typified by slit  124  shown in  FIGS. 3 a   - 3 C, which cooperate together to render the distal end region  114 , and the distal tip  116  especially, flexible in any direction or plane and be compliant with the shape of a companion outer catheter (features of which are shown and discussed elsewhere in this disclosure). The needle/electrode  125  includes a piercing tip  126 . This tip is electrically coupled via wire  120  to the electrical connector port  130  (shown in  FIGS. 1-2 ). The distal assembly casing  118  tapers to a small diameter at the distal tip  116  and serves as a dilation surface  132 ; whereby when the distal tip  116  is advanced into the heart  1000  and through the wound cite (opening)  1002  in the septum  1010 , created by the piercing tip  126 ; the dilatation surface  132  acts to open the wound cite  1002  further to allow the catheter assembly  100  better access into the left atrium  1020 , from the right atrium  1015 , such as is depicted in  FIG. 17  and discussed in greater detail below. 
         [0052]    Returning to  FIGS. 3 a -3 c   , the hypo-tube  122  and needle/electrode  125  also define a central guidewire lumen  140  through which a guidewire  142  is positioned to aid in advancing the catheter assembly  100  (and the joined multiple catheter assembly system  500  discussed in greater detail below) to the treatment cite. 
         [0053]    In  FIG. 3 a    the first catheter assembly  100  is shown with the needle/electrode  125  in the retracted position with the guidewire  142  in place within the lumen  140 . Such a configuration is representative of how the assembly  100  is arranged during advancement through the vascular anatomy along the guidewire  142  and into the right atrium  1015  of the heart  1000  such as is shown in  FIG. 14 . 
         [0054]    In  FIG. 3 b    the needle/electrode  125  is shown in the extended position, wherein it extends out of the casing  118  and beyond the distal tip  116  of the first catheter assembly  100 , with the guidewire  142  still in place. 
         [0055]    In  FIG. 3 c   , the guidewire  142  has been proximally withdrawn through the lumen  140  to allow the needle/electrode  125  unimpeded access to the septum  1002  such as in the manner shown in  FIG. 17 . 
         [0056]      FIG. 4  shows a cross-sectional view of the distal end region  114  components including the housing or casing  118 , the wire  120 , the hypo-tube  122  and guidewire lumen  140 . An inherent feature of this arrangement is that the casing  118  defines a hypo-tube lumen  119  in which the hypo-tube  122  (and the distal end portion of which is the needle/electrode  125 ) is moveable (retraction and extension via thumb slide  106  discussed above) therein. 
         [0057]    As mentioned above, in at least some embodiments the first catheter assembly  100  is the “inner” catheter of a multiple catheter system  500  wherein one of two types of “outer” catheters are used in conjunction there with. Such outer catheter assemblies and their manner of use with the first catheter assembly  100  are shown in  FIGS. 5-13  and are discussed below. For simplicity the two types of “outer” catheters are identified as a second catheter assembly  200  (shown in detail in  FIGS. 5-8 ) and a third catheter assembly  300  (shown in  FIGS. 9-13 ) respectively. 
       Outer Catheter Option One-Second Catheter Assembly: 
       [0058]      FIG. 5 a    shows the distal end region  114  of the first catheter assembly  100  that has been inserted into the second catheter assembly  200 . The handle  104  of the first catheter assembly is coupled to the handle  204  of the second catheter assembly  200  by advancing the entire casing  118  of the distal end region  114  of the first catheter assembly  100  into and through a receiving lumen  201  defined by the handle  204  and distal end region  214  of the second catheter assembly  200 , in the manner show in  FIG. 5 b   , until the handles  104  and  204  are properly engaged and locked together in the manner described below. 
         [0059]    In  FIG. 5 b    an embodiment of a system  500  is shown wherein various mechanism are provided to ensure proper coupling between the handles  104  and  204 . For example, the relative shapes of the handles  104  and  204  provide a natural aligning feature, whereby the narrower bottom portion or torque handle  250  of the handle  204  is longitudinally aligned with the protrusion of the connector port  130  of the handle  104 . Another alignment mechanism is the presence of a visual guide or indicator slot  252  present on the distal surface  254  of the handle  204 . This slot  252  provides a user with a visual guide whereby a corresponding protrusion (not show) on the handle  104  engages the slot  252  as the first catheter assembly  100  is coupled to the second catheter assembly  200  in the manner shown in  FIG. 5 b   . If the proper longitudinal alignment between the handles  104  and  204  is not achieved, such as is depicted in  FIG. 5 c   , the assemblies  100  and  200  cannot be properly coupled. Finally, a third mechanism may be provided such as is shown in  FIG. 5 d   . In the embodiment shown in  FIG. 5 d   , a direct coupling mechanism  260  is provided whereby an engagement shaft  162  of the first catheter assembly  100  is received into an end cap assembly  262  of the second catheter assembly  200 . The engagement shaft  162  and end cap assembly  262  may respectively include any of a variety of structural protrusions, indentations or similar features to provide a “snap fit” and/or “lock and key” style interface between the two handles  104  and  204 . In the specific embodiment shown the end cap assembly  262  includes a flat “rib”  264 , which a correspondingly shaped groove  164  on the engagement shaft  162  slides over and receives so as prevent any relative rotational movement between the coupled first and second catheter assemblies. A detailed longitudinal sectional view of the first catheter assembly  100  and second catheter assembly  200  being properly aligned and coupled together to form a system  500  is shown in  FIG. 6 . 
         [0060]    Referring now to the second catheter assembly  200  in more detail as depicted in  FIGS. 7 a -7 e    and in the sectional view of the handle  204  of  FIG. 8 , there is shown the entire second catheter assembly  200 , which is also known as a guiding vascular introducer device comprised of a distal tubular section  214  that traverses through the handle  204 . The distal tubular section  214  has a curved tip section  216 . The handle  204  is further comprised of a side port tube  230 . The external part of the side port tube  230  is located at the distal end of the handle  204  as shown best in  FIGS. 7 a , 7 b  and 7 e   . In these same figures there is shown a strain relief  222  at the junction of the distal tubular section  214  and handle  204  as well as a canted pass-through aperture  232  for the side port tube  230  to enter the handle  204 . 
         [0061]    The construction details of the invention are selected such that the useable length of the distal tubular section  214 ; including its curved tip section  216 , shall be sufficient to reach from a patient&#39;s vascular insertion site, in the groin area, to the left atrium of their heart, typically 50 to 75 centimeters, but may be longer in taller patients. The inner diameter of the distal tubular section  214 , including its curved tip section  216 , shall be sufficient to accommodate various catheter devices, typically 5 French (1.65 mm) to 12 French (3.96 mm). The distal tubular section  214 , including its curved tip section  216 , shall be made of a medical grade polymer and may include wire braiding within its wall. The distal tubular section  214 , including its curved tip section  216 , may have coatings on its patient-contacting surfaces to provide lubricity and/or deter the formation of blood clots. 
         [0062]    The side port tube  230  shall be made of a medical grade polymer and have an external length of approximately 5 to 20 centimeters. The handle  204  shall be a length sufficient to efficiently manipulate the introducer with the thumb and 3-5 fingers, typically between 3-5 centimeters. Furthermore, the handle  204  shall be of shape that provides an intuitive directional indicator (as discussed above) that is in plane with the curved tip section  216 . One such shape is an inverted teardrop, as depicted in  FIGS. 5 a -5 c   . The handle  204 , including the canted pass-through aperture  232 , shall be made of one or more medical grade thermoplastics such as polycarbonate, polyethylene, or nylon. 
         [0063]    With specific regard to  FIG. 8 , within the handle  204  is shown a catheter access port  234 . Of note, the side port tube  230  and distal tubular section  214  exit from the handle  204  in a parallel orientation (as is shown in  FIG. 7 b -7 d   ). Port  234  includes a hemostasis valve housing  270  and mounting stem  272 . The hemostasis valve housing  270  and integral mounting stem  272  are made of a medical grade thermoplastic such as polycarbonate, polyethylene, or nylon. The distal tubular section  214  is connected to the hemostasis valve housing  270  via injection molding or medical grade adhesive. The entire valve housing  270  shall be contained internally within the handle  204 . The side port tube  230  is connected to the mounting stem  272  via medical grade adhesive. 
         [0064]    Side port tube  230  include an access valve or stop-cock  280  along with an ancillary engagement port  282 . Via this port and valve, various ancillary devices may be employed in conjunction with the secondary catheter assembly such as infusion pumps, drug delivery systems, and other diagnostic or therapeutic tools. 
         [0065]    The advantages of the present invention include, without limitation, is that it allows the operator to efficiently torque the second catheter assembly  200  during a procedure. Typically, the operator only has a small hemostasis valve housing to serve as a torque handle. Furthermore, by removing the side port tube from the primary area of device manipulation eliminates the risks of interfering with operation and entangling with, and possibly dislodging, an adjacent device. Finally, the addition of a biomimetic coating on the patient-contacting surfaces with mitigate the risks of thrombogenesis, or the production of blood clots, which may lead to such adverse effects as stroke, myocardial infarction, or pulmonary embolus, all of which may be fatal. 
         [0066]    In broad embodiment, the present invention is a guiding vascular introducer designed with an ergonomic torque handle with features that promote efficient and an improved safety profile. 
       Outer Catheter Option One —Third Catheter Assembly: 
       [0067]      FIGS. 9 a -9 e    illustrate various views of the second outer catheter option mentioned above, and hereinafter referred to as the third catheter assembly  300 . The third catheter assembly  300  includes a proximal handle  304  and a distal end region  314 . A side port tube  330  with a stop-cock  380  and ancillary engagement port  382  is also included in the third catheter assembly  300  and is used in the same manner for connecting ancillary systems and devices to the catheter, as the corresponding structures of the second catheter  200  assembly discussed above. 
         [0068]    The third catheter assembly includes with the handle  304  a control knob  306  which is mechanically engaged to the distal tip  316  of the distal end region  314 , whereby when the knob  306  is turned (by a user) the distal tip  316  moves relative to the longitudinal axis  108  of the distal end region  314  a specified distance and angle in the manner depicted in  FIG. 13 . 
         [0069]    In the same manner as is shown in  FIGS. 5 a -5 c    between the second catheter assembly  200  and the first catheter assembly  100 , alignment between the third catheter assembly  300  and the first catheter assembly  100  must be achieved so as to allow their respective handles  104  and  304  to be coupled together such as in the manner depicted in  FIGS. 10 b  and 10 a   , so as to form a system  500 . When improperly aligned, such as in the manner shown in  FIG. 10 c   , the handles  304  and  104  are incapable of being coupled together. Proper alignment of the handles  304  and  104  may be the same sort of mechanisms described in  FIGS. 5 a -5 c    above. In the embodiments shown in  FIGS. 10 a -10 c    for example, the handle  304  includes a visual and mechanical guide in the form of an engagement slot  352  with which a user simply lines up the thumb slide  106  of the handle  104 . If properly aligned, the slot  352  of the handle  304  will receive a protrusion or other feature (not shown) on the handle  104  to ensure proper coupling of the two handles  104 ,  304  when the first catheter assembly  100  is inserted into the lumen  301  of the third catheter assembly  300  in the manner shown in  FIG. 10   b.    
         [0070]    Turning now to the specifics of the third catheter assembly  300 , as is best shown in  FIGS. 11 a -11 d   , the third catheter assembly distal end region  214  extends from the distal end of handle  304  (and which receives the distal end region  114  of the first catheter assembly  100  therein) while the control knob  306  is located near the proximal end of the handle. The control knob turns on a control axis  310  defined by axle  312  orthogonal to the third catheter assembly&#39;s longitudinal axis  108 . 
         [0071]    In use the physician turns the control knob  306  with his left hand and uses the thumb of the left hand to activate the control button  325 . When this button is depressed as in the direction depicted at ref numeral arrow  327  the tooth  329  disengages from lock pinion gear  341 . In the depressed or activated state (shown in  FIG. 11 b   ) the motion of the knob  306  is unlocked and the control knob  306  may be turned to steer or flex the distal tip  318  of the device. When control button  325  is released the tooth  329  is urged, by spring pressure of compression spring  343 , back into position against the gear  341  to lock the knob&#39;s motion (and thus the position of the distal tip  316  as may be seen in  FIGS. 12-13 ) in place. 
         [0072]      FIGS. 12 a -12 d    show the third catheter assembly  300  wherein the knob  306  is at rest or unactuated ( FIG. 12 b   ) and is fully actuated in a first direction ( FIG. 12 d   ). As can be seen, this activation and rotation of the control knob  306  causes the highly flexible distal tip  316  of the assembly to be drawn in different directions depending on the direction and extent that the control knob  306  if rotated. The flexible nature and degree of the distal tip&#39;s movement relative to the longitudinal axis  108  is shown in more detail in  FIG. 13 . 
         [0073]    In the embodiments shown, the particular arrangement of components which allows the distal tip  316  to move in the manner described above is shown in more detail in the sectional views of  FIGS. 11 c -11 d   . As can be seen in these images, the pinion gear  341  (shown in  FIGS. 11 a  and 11 b   ) engages both rack  350  and rack  352 . Rotation of the pinion gear  341  (via actuation of the button  325  and rotation of the knob  306  as described above) drives the racks  350  and  352 , with each rack driven in the opposite direction. Cable anchor  354  and cable anchor  356  are moved with respect to each other providing traction to the pulls wires  357  and  359  (partially shown, and which extend distally to the distal tip) that deflect the deflectable distal tip  316  through an arc in a plane as depicted in  FIG. 13 . 
         [0074]      FIGS. 12 a -12 b    show the deflectable distal tip  316  in its un-deflected state corresponding to the rack positions seen in  FIG. 11 c   .  FIGS. 12 c -12 d    show the deflectable tip  316  moving through a  180  arc driven by pull wire  357  and pull wire  359 , each connected to its respective cable anchor  354  or  356 . This curvature corresponds to the rack positions seen in  FIG. 11 d   . 8 .  FIGS. 10 a -10 c    shows an intermediate position corresponding to a deflection of approximately 90 degrees. 
         [0075]    The construction details of the invention as shown in the preceding figures are that the useable length of the distal tubular section  314  shall be sufficient to reach from a patient&#39;s vascular insertion site, in the groin area, to the left atrium of their heart, typically 50 to 75 centimeters, but may be longer in taller patients. As is well known only the proximal and distal section of the catheters illustrated to facilitate disclosure of the invention and the inventive features in the most proximal and distal areas of the catheters. The inner diameter of the distal tubular section  314  shall be sufficient to accommodate various catheter devices, typically 5 French (1.65 mm) to 12 French (3.96 mm). The distal tubular section  314  shall be made of a medical grade polymer and may include wire braiding within its wall. The distal tubular section  314  may have coatings or a biomimetic surface on its patient-contacting surfaces to provide lubricity and/or deter the formation of blood clots. The side port tube shall be made of a medical grade polymer and have an external length of approximately 5 to 20-centimeters. The control knob  306  may be configured as a rotatable wheel, rotatable coaxial collar, slide, or lever. 
       Method of Use 
       [0076]    The various combinations of catheter assemblies  100 ,  200  and/or  300  as shown and described above, are (as has been mentioned) to be utilized as a system  500  for conducting a method of accessing the left heart from the right heart following advancement of the system  500  through the vasculature of a patient. 
         [0077]    For example, the following stepwise sequence can be used to carry out the method of the invention:
       1. A physician or technician uses the Seldinger procedure to gain access to the femoral vein with a conventional needle puncture.   2. A long guidewire  142  is inserted through the needle and advanced under fluoroscopic guidance to the superior vena cava (SVC) such as is depicted in  FIG. 14 . As seen in  FIG. 14  the guidewire  142  extends out of the distal tip and the location above the SVC is confirmed fluoroscopically. A small amount of contrast agent may be injected into the heart to visualize and confirm the location above the SVC.   3. Next, withdraw the needle over the wire leaving the wire  142  in place.   4. As seen in  FIG. 15 , the first catheter and third catheter assembly or first catheter assembly-second catheter assembly system  500  is advanced to the heart  1000  over the guidewire  142  and to the SVC.   5. Pull the guidewire  142  into the first catheter assembly.   6. Rotate the first catheter assembly-third catheter assembly or first catheter assembly-second catheter assembly system  500  to point medial as to be perpendicular to the plane of the interarterial septum  1010 .   7. Connect an extension lead  131 , such as is shown in  FIG. 2 c   , between the connector port  130  of first catheter assembly  100  and an EMG recording system  133  to display unipolar signal from the needle/electrode  125  of first catheter assembly  100 . In general a Wilson central terminal technique is used to provide the ground reference for the unipolar system. In this technique several surface electrode patches on the patient are taken collectively as the ground reference.   8. Maintaining system alignment by monitoring the system  500  via fluoroscopic imaging, electro gram and/or optional ultrasound imaging to locate the fossa ovalis  1002  such as is depicted in  FIG. 15  by pulling the catheter assembly down along a path indicated by motion arrow  2010  while observing the electro gram shown in  FIG. 16  where the characteristic wave form of the high septum location is seen at reference numeral  2000 .   9. Once the fossa ovalis location has been reached as seen in  FIG. 17 , as confirmed by the characteristic waveform  2020  seen in  FIG. 18  the physician is ready to pierce the heart wall. This is achieved by holding the system securely and actuate the thumb lever  106  to advance the piercing tip  126  through the fossa ovalis.   10. Optionally confirm presence in the left atrium via contrast injection (via side access ports  282 / 382  as previously shown and described) of pressure recording, and advance the guidewire  142  into the left atrium  1020 , such as in the manner shown in  FIG. 17 .   11. Release the thumb lever  106  automatically retracting the piercing tip  126  under the force supplied by spring  112 .   12. Advance system  500  into the left atrium  1020  while monitoring the electro gram which will have the form of the characteristic waveform  2060  seen in  FIG. 19 .  FIG. 22  shows the catheter assembly roving in the left heart with characteristic waves forms shown as taken from locations depicted as a circle  2030  high on the atrial wall showing a wave form  2035 , while location circle  2050  is a location near the valve structures resulting in a characteristic wave form  2055 . Location circle  2040  is corresponds to floating in the chamber and its wave form is seen at  2055 .   13. Holding the system securely release and uncouple first catheter assembly and push sheath toward tip of first catheter assembly.   14. With the sheath near the wall of the atrium The first catheter assembly is withdrawn form the sheath, and the sheath is aspirated and flushed with heparinized saline. The sheath is now placed for the desired intervention such as ablation or device placement.       
 
         [0092]    With respect to the step  7  and the exploratory phase of the method, a full set of waveforms is seen in  FIG. 20  and  FIG. 21 . These are representative of the situation with the catheter electrode tip roving in the LA. Trace  2060  and  2065  corresponds to the surface electro gram of the patient, trace  2070  and  2075  corresponds to the His bundle recording. Trace  2080  and  2085  corresponds to the electro gram taken from the coronary vessels while trace  2100  and  2105  are the pressure traces taken from several sensors. Of importance is trace  2090  and  2095  which is the tracing from the needle electrode retracted in its sheath.