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

OBJECTIVE We examined the feasibility and efficacy of using a single-pass, dual-electrode (Solo) lead for atrial fibrillation (AF) detection and defib rillation. BACKGROUND The efficacy and safety of an implantable atrial defibrillator ( LAD) 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 defibrilla tion in 17 patients who underwent cardioversion of chronic AF. The Solo lea d with a proximal 6-cm RA electrode and a distal 6-cm spiral-shaped CS elec trode were positioned into the CS with the Rtl electrode against the antero lateral RA wall. The RA-CS electrogram signal amplitudes were measured and the efficacy of the Solo lead for AF detection and defibrillation was asses sed by using an external version of the LAD. 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 48 4 +/- 229 mu V during sinus rhythm and 274 +/- 88 mu V during AF (p < 0.05) . All patients had satisfactory atrial signal amplitude to allow accurate d etection of sinus rhythm. Successful cardioversion was achieved in 16/17 (9 4%) patients with an atrial defibrillation threshold of 320 +/- 70 V (5.5 /- 2.7J). Insufficient interelectrode spacing resulted in suboptimal electr ode locations, associated with a lower atrial signal amplitude, a higher at rial defibrillation threshold and diaphragmatic stimulation. CONCLUSIONS These results suggest a simplified lead configuration with opti mal interelectrode spacing can be used with an IAD for AF detection and def ibrillation. (C) 1999 by the American College of Cardiology.