Decreasing the number of leads required for an implantable atrial defibrillator: Use of a new 2-lead system

Background The purpose of this study was to evaluate the use of a new 2-lead system for detection of atrial fibrillation (AF) and atrial defibrillation. Methods In 16 patients undergoing elective cardioversion of AF, a 2-lead system was compared with the conventional 3-lead system in a randomized trial. The new 2-lead system consisted of a catheter with a distal bipolar right ventricular electrode pair and a proximal right atrial shock electrode coil and a separate decapolar defibrillation catheter in the coronary sinus. For the 3-lead system, an additional decapolar catheter was placed in the right atrium. AF and sinus rhythm signal amplitude detection and atrial defibrillation threshold (ADFT) were compared in each patient with both systems. Results Successful defibrillation was obtained in all patients. ADFT for the 2-lead system was significantly higher compared with the 3-lead system (370 ± 112 vs 316 ± 100 V, P < .05; 9.3 ± 5.2 vs 6.8 ± 4.2 J, P < .05). In contrast, there was an increase in impedance for the 3-lead system (77 ± 16 Ω vs 68 ± 13 ω; P < .05). AF had a lower signal amplitude compared with sinus rhythm for both systems (P < .05), and the 2-lead system had a lower signal amplitude compared with the 3-lead system for both rhythms (P < .05). Conclusion The use of a 2-lead system with this configuration is not superior to the 3-lead system regarding AF signal amplitude detection and ADFT. Further study is needed with implantable-quality leads in place of the temporary catheters used in this study. (Am Heart J 2000;140:e11.)