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

Abstract

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 μV during sinus rhythm and 274 ± 88 μV 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.