Dual current pathway atrial defibrillation apparatus

An implantable system for the defibrillation of the atria of a human patient's heart, said system comprising:

• a first defibrillation electrode configured for positioning in the right atrium or superior vena cava of said heart;
• a second defibrillation electrode configured for positioning in the distal coronary sinus or great cardiac vein of said heart;
• a pulse generator operatively associated with said first and second defibrillation electrodes for delivering a first defibrillation pulse not greater than 8 Joules between said first and second electrodes;
• a third defibrillation electrode configured for positioning in the proximal coronary sinus of said heart;
• a fourth defibrillation electrode configured for positioning anterior to the left atrium of said heart;
• and
• a pulse generator operatively associated with said third and fourth defibrillation electrodes for delivering a second defibrillation pulse not greater than 8 Joules between said third and fourth electrodes after said first defibrillation pulse and without intervening monitoring of the efficacy of the first defibrillation pulse.

A lead for insertion into the heart of a patient for use in combination with an atrial defibrillator, said lead comprising:

• an elongate catheter flexibly configured for insertion down the superior vena cava of the heart, into the right atrium, through the right ventricle, and into the pulmonary artery to achieve an operable configuration therein;
• a first atrial defibrillation electrode connected to said catheter;
• and
• a second atrial defibrillation electrode connected to said catheter;
• said first and second atrial defibrillation electrodes spaced apart on said catheter so that, when said catheter is in said operable configuration,
• said first atrial defibrillation electrode is positioned in the right atrium of the heart;
• and
• said second atrial defibrillation electrode is positioned in the pulmonary artery;
• and
• a third electrode connected to said catheter;
• said third electrode spaced apart from said first and second atrial defibrillation electrodes so that, when said catheter is in said operable configuration, said third electrode is positioned in the left ventricle of the heart.