title: Lead systems for atrial defibrillation.
abstract: In summary, these five studies show that electrode locations that include both left and right atrium result in lower thresholds. Thresholds from right atrium to chest wall patch are higher than thresholds from right atrium to cardiac vein, suggesting that confinement of the electric field by a transvenous electrode system is advantageous. Of the transvenous locations tested, the right atrial appendage to left atrial appendage defibrillation vector consistently had the lowest defibrillation energy threshold. The proximal coronary sinus to right atrial vector may be inappropriate due to the high thresholds observed. The large variability of the mean threshold for the obtuse marginal location in the cardiac vein vasculature suggests that this vector may result in higher thresholds in some instances. Electrode locations that have high defibrillation thresholds and are in close proximity to the sinoatrial or atrioventricular node increase the likelihood of sinus arrhythmias or conduction block following the defibrillation shocks. No difference was detected between the thresholds between the single catheter, two electrode system and the two catheter system, despite the variability of location of the electrode in the right atrium, suggesting that such a catheter may provide a simpler implantation procedure and equivalent thresholds in some patients. These findings suggest that coronary sinus/great cardiac vein catheter designs should strive for implantation in the distal portion of the great cardiac vein so that the shocking electrode underlies the left atrium with the other shocking electrode located in the right atrium.
authors.affiliation: InControl, Inc., Redmond, WA 98052-6734.
authors.forename: C
authors.initials: C
authors.lastname: Alferness
authors.forename: G M
authors.initials: GM
authors.lastname: Ayers
authors.forename: R A
authors.initials: RA
authors.lastname: Cooper
authors.forename: R E
authors.initials: RE
authors.lastname: Ideker
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000628:therapy*; D004554:Electric Countershock / Q000295:instrumentation* / Q000379:methods; D004567:Electrodes, Implanted; D006325:Heart Atria; D012756:Sheep