referring now to the drawings in detail wherein like reference numerals have been used throughout the various figures to designate like elements , there is shown in fig1 a catheter constructed in accordance with the principles of the present invention and designated generally as 10 . in a first embodiment of the present invention , as seen in fig1 the catheter 10 essentially includes an elongated flexible member 12 which may be made of polyurethane . however , the flexible member 12 may be made from a variety of materials such as silicone rubber or plasticized pvc . the flexible member 12 is preferably approximately 110 centimeters long with an outside diameter of approximately 2 . 5 millimeters . as should be readily apparent to those skilled in the art , only the working portion of the catheter 10 is shown in the drawings . the working portion of the flexible member 12 has a proximal end 14 and a distal end 16 . carried on the working portion of the flexible member 12 of the catheter 10 are first , second , and third spaced apart electrode arrays , the details of which will be described hereinafter . electrical wires ( not shown ) from the electrode arrays pass through the interior of the flexible member 12 to a manifold secured to the remote end of the flexible member 12 for connecting the catheter 10 to appropriate electronic equipment . located adjacent the proximal end 14 is the first electrode array . the array includes approximately ten electrodes 18 a - 18 j where each electrode has an approximate length of five millimeters and each electrode is spaced approximately five millimeters away from each adjacent electrode . the second electrode array , located distal to the first array , consists of approximately twelve electrodes 20 a - 20 l . the length of each of these electrodes is also approximately five millimeters and each electrode is spaced approximately five millimeters away from each adjacent electrode . the third electrode array , located adjacent the distal end 16 consists of approximately seven electrodes 22 a - 22 g . the length of each of these electrode is approximately five millimeters and each is spaced approximately ten millimeters away from each adjacent electrode . located within the second array of electrodes 20 a - 20 l is an atrial pacing / sensing electrode 24 . also , located at the distal end 16 of the flexible member 12 are bi - polar pacing / sensing stimulation electrodes 26 a and 26 b . a steering arrangement known in the art may be associated with the catheter 10 in order to direct the placement of the electrode arrays . in order to perform a defibrillation procedure , the flexible member 12 is introduced into the vascular system from the jugular area in a manner known in the art . the flexible member 12 is then guided into the patient &# 39 ; s heart 28 until it is placed in the desired position . the flexible member 12 is positioned so that the first electrode array 18 a - 18 j is positioned within the superior vena cava 30 , the second electrode array 20 a - 20 l is positioned within the right atrium 32 , and the distal end 16 with the third electrode array 22 a - 22 g is positioned within the coronary sinus 34 . with the flexible member 12 properly in place , electric shocks are applied through the catheter in order to defibrillate the patient &# 39 ; s heart 28 . this is accomplished by connecting the contact pin ( not shown ) at the proximal end of the proximal lead ( not shown ) attached to the first and second electrode arrays and the contact pin ( not shown ) of the distal lead of the third electrode array to an appropriate power source . thereafter , low energy electrical current is supplied through the electrical leads to the corresponding electrode arrays in order to achieve a normal sinus rhythm in the patient . more specifically , the atrial pacing / sensing electrode 24 and the bi - polar pacing / sensing stimulation electrodes 26 a and 26 b , sense the occurrence , if any , of fibrillation . if fibrillation is sensed , the heart 28 is defibrillated or cardioverted by the application of at least one electrical shock between the first and second arrays of electrodes 18 a - 18 j and 20 a - 20 l , respectively , which are connected to the proximal electrical lead and the third array of electrodes 22 a - 22 g which is connected to the distal electrical lead . the two proximal common arrays 18 a - 18 j and 20 a - 20 l on the catheter are coupled together as an anode and the single array 22 a - 22 g on the distal end 16 of the catheter is a cathode . the polarity of the arrays can be reversed to attempt lower defibrillation thresholds in certain patients . approximately 1 - 50 joules of energy are discharged through the sinoatrial node and the atrioventricular node to terminate atrial fibrillation . in a second embodiment of the present invention , as seen in fig2 the catheter 110 , similar to the catheter of the first embodiment , includes an elongated flexible member 112 which may be made of the same types of materials and have the same dimensions as discussed above . again , only the working portion of the catheter 110 is shown . the working portion of the flexible member 112 has a proximal end 114 and a distal end 116 . carried on the working portion of the flexible member 112 of the catheter 110 are first , second ; and third spaced apart electrode arrays , the details of which will be described hereinafter . electrical wires ( not shown ) from the electrode arrays pass through the interior of the flexible member 112 to a manifold secured to the remote end of the flexible member 112 for connecting the catheter 110 to appropriate electronic equipment . located adjacent the proximal end 114 is the first electrode array . the array includes approximately ten electrodes 118 a - 118 j where each electrode has an approximate length of five millimeters and each electrode is spaced approximately five millimeters away from each adjacent electrode . the second electrode array , located distal to the first array , consists of approximately twelve electrodes 120 a - 120 l . the length of each of these electrodes is also approximately five millimeters and each electrode is spaced approximately five millimeters away from each adjacent electrode . the third electrode , located adjacent the distal end 116 consists of approximately seven electrodes 122 a - 122 g . the length of each of these electrode is approximately five millimeters and each is spaced approximately ten millimeters away from each adjacent electrode . located within the second array of electrodes 120 a - 120 l is an atrial pacing / sensing electrode 124 . also , located at the distal end 116 of the flexible member 112 are bi - polar pacing / sensing stimulation electrodes 126 a and 126 b . a steering arrangement known in the art may be associated known with the catheter 110 in order to direct the placement of the electrode arrays . in order to perform a defibrillation procedure , the flexible member 112 is introduced into the vascular system from the jugular area in a manner known in the art . the flexible member 112 is then guided into the patient &# 39 ; s heart 128 until it is placed in the desired position . the flexible member 112 is positioned so that the first electrode array 118 a - 118 j is positioned within the superior vena cava 130 , the second electrode array 120 a - 120 l is positioned within the right atrium 132 , and the distal end 116 with the third electrode array 122 a - 122 g is positioned within the right ventricle 134 instead of the coronary sinus , as in the first embodiment , in an attempt to obtain lower defibrillation thresholds . with the flexible member 112 properly in place , electric shocks are applied through the catheter in order to defibrillate the patient &# 39 ; s heart . this is accomplished by connecting the contact pin ( not shown ) at the proximal end of the proximal lead ( not shown ) attached to the first and second electrode arrays 118 a - 118 j and 120 a - 120 l , respectively , and the contact pin ( not shown ) of the distal lead of the third electrode array 122 a - 122 g to an appropriate power source . thereafter , low energy electrical current is supplied through the electrical leads to the corresponding electrode arrays in order to achieve a normal sinus rhythm in the patient . more specifically , the atrial pacing / sensing electrode 124 and the bi - polar pacing / sensing stimulation electrodes 126 a and 126 b , sense the occurrence , if any , of fibrillation . if fibrillation is sensed , the heart 128 is defibrillated or cardioverted by the application of at least one electrical shock between the first and second arrays of electrodes 118 a - 118 j and 120 a - 120 l , respectively , which are connected to the proximal electrical lead and the third array of electrodes 122 a - 122 g which is connected to the distal electrical lead . the two proximal common arrays 118 a - 118 j and 120 a - 120 l on the catheter are coupled together as an anode and the single array 122 a - 122 g on the distal end 116 of the flexible member 112 is a cathode . the polarity of the arrays can be reversed to attempt lower defibrillation thresholds in certain patients . as in the first embodiment , approximately 1 - 50 joules of energy are discharged through the sinoatrial node and the atrioventricular node to terminate atrial fibrillation . it should be noted that in both of the embodiments , a continuous flexible electrode may be substituted for any or all of the electrode arrays . this ensures that the electrode is sufficiently flexible so that the same can be easily bent and straightened , as desired , without causing damage to the same . such an electrode is preferably formed by a process of ion - beam assisted deposition ( ibad ). this technology is described in detail in each of u . s . pat . nos . 5 , 468 , 562 ; 5 , 474 , 797 ; and 5 , 492 , 763 , the disclosures of which are incorporated herein by reference . the use of this technique for forming an electrode catheter is also described in co - pending application ser . no . 08 / 751 , 436 , filed on nov . 20 , 1996 , entitled “ temporary atrial defibrillation catheter with improved electrode configuration and method of fabrication .” the subject matter of this co - pending application , commonly owned , is also incorporated herein by reference . the electrodes may also be applied by sputtering , vacuum deposition , printing , or spraying . an advantage of the present system is that it is easy to use because only one catheter is needed . that is , the three electrode arrays are combined onto one single catheter . it is far easier and faster for physicians to place one catheter , as opposed to two separate devices , in a patient . also , it is less traumatic and safer for the patient to have one catheter placed within his or her body as opposed to two or more devices . another advantage of the present system is that it is easier to use than pulmonary artery defibrillation catheters because electrophysiologists are more familiar with superior vena cava , right atrium , and coronary sinus catheter placement which is routinely used in their practice as opposed to pulmonary artery placement which is used more in pressure monitoring in critical care . the present invention may be embodied in other forms without departing from the spirit or essential attributes thereof and accordingly , reference should be made to the claims rather than to the foregoing specification as indicating the scope thereof .
a catheter for facilitating intracardiac atrial defibrillation that includes an elongated flexible member that has a proximal end and a distal end is disclosed . three spaced apart electrode arrays are secured around the periphery of the flexible member in a predetermined pattern so that a first electrode array is positioned within the superior vena cava , a second electrode array is positioned within the right atrium , and a third electrode array is positioned within the coronary sinus . alternatively , the third electrode array may be positioned in the right ventricle rather than the coronary sinus . electrical leads extend through the proximal end of the flexible member to supply electrical current to the electrode arrays , thereby defibrillating or cardioverting the heart .