LOW-ENERGY TRANSVENOUS CARDIOVERSION OF ATRIAL-FIBRILLATION USING A SINGLE ATRIAL LEAD SYSTEM

Introduction: Clinical studies have shown that electrical conversion o f atrial fibrillation (AF) is feasible with transvenous catheter elect rodes at low energies, Wie developed a single atrial lead system that allows atrial pacing, sensing, and defibrillation to improve and facil itate this new therapeutic option. Methods and Results: The lead consi sts of a tripolar sensing, pacing, and defibrillation system, Two defi brillation coil electrodes are positioned on a stylet-guided lead. A r ing electrode located between the two coils serves as the cathode for atrial sensing and pacing. We used this lead to cardiovert patients wi th acute or chronic AF, The distal coil was positioned in the coronary sinus, and the proximal coil and the ring electrode in the right atri um. R wave synchronized biphasic shocks were delivered between the two coils. Atrial signal detection and pacing were performed using the pr oximal coil and the ring electrode, Eight patients with acute AF (38 /- 9 min) and eight patients with chronic AF (6.6 +/- 5 months) were i ncluded. The fluoroscopy time for lead placement was 3.5 +/- 4.3 minut es. The atrial defibrillation threshold was 2.0 +/- 1.4 J for patients with acute AF and 9.2 +/- 5.9 J for patients with chronic AF (P < 0.0 1), The signal amplitude detected was 1.7 +/- 1.1 mV during AF and 4.0 +/- 2.9 mV after restoration of sinus rhythm (P < 0.001). Atrial paci ng was feasible at a threshold of 4.4 +/- 3.3 V (0.5-msec pulse width) . Conclusions: Atrial signal detection, atrial pacing, and low-energy atrial defibrillation using this single atrial lead system is feasible in various clinical settings. This system might lead to a simpler, le ss invasive approach for internal atrial cardioversion.