Implantable atrial defibrillator with a single-pass dual-electrode lead.

OBJECTIVES We examined the feasibility and efficacy of using a single-pass, dual-electrode (Solo) lead for atrial fibrillation (AF) detection and defibrillation. BACKGROUND The efficacy and safety of an implantable atrial defibrillator (IAD) has been extensively studied; however, separate right atrial (RA) and coronary sinus (CS) defibrillation leads are used for the present system. METHODS We studied the use of the Solo lead for AF detection and defibrillation in 17 patients who underwent cardioversion of chronic AF. The Solo lead with a proximal 6-cm RA electrode and a distal 6-cm spiral-shaped CS electrode were positioned into the CS with the RA electrode against the anterolateral RA wall. The RA-CS electrogram signal amplitudes were measured and the efficacy of the Solo lead for AF detection and defibrillation was assessed by using an external version of the IAD. RESULTS The leads were inserted in all patients without complication (mean fluoroscopy time: 13.3+/-6.8 min). The mean RA-CS signal amplitude was 484+/-229 microV during sinus rhythm and 274+/-88 microV during AF (p < 0.05). All patients had satisfactory atrial signal amplitude to allow accurate detection of sinus rhythm. Successful cardioversion was achieved in 16/17 (94%) patients with an atrial defibrillation threshold of 320+/-70 V (5.5+/-2.7 J). Insufficient interelectrode spacing resulted in suboptimal electrode locations, associated with a lower atrial signal amplitude, a higher atrial defibrillation threshold and diaphragmatic stimulation. CONCLUSIONS These results suggest a simplified lead configuration with optimal interelectrode spacing can be used with an IAD for AF detection and defibrillation.