Clinical experience with a dual-chamber implantable cardioverter defibrillator to treat atrial tachyarrhythmias

Dual-Chamber ICD and Atrial Tachyarrhythmia. Introduction: This study evalu ated the safety and efficacy of a new dual-chamber implantable cardioverter defibrillator (ICD) to detect and treat atrial tachyarrhythmias in patient s with drug-refractory atrial fibrillation (AF) and no indication for a ven tricular ICD. Methods and Results: A dual-chamber ICD (Medtronic 7250 Jewel AF) was impla nted in 144 of 146 patients. The device discriminates atrial tachycardia fr om AF based on cycle length and regularity, and uses atrial overdrive pacin g as well as shocks to terminate tachyarrhythmia episodes. Patients were fo llowed for an average of 12.6 +/-6.2 months. Use of antiarrhythmic drugs wa s 63% at baseline and did not change over time. Kaplan-Meier estimates of 1 2-month complication-free survival, device therapy survival, and patient su rvival were 85%, 91%, and 98%, respectively. Positive predictive accuracy o f spontaneous atrial tachyarrhythmia detection was 99%, while atrial overdr ive pacing and shocks terminated 40% and 87% of treated episodes, respectiv ely. Median duration of successfully treated episodes was 8.9 minutes versu s 144 minutes for the therapy failures. There was no reduction in the use o f patient-activated shock therapy over time; at the 12-month follow-up eval uation, 94% of patients were in sinus rhythm. Ventricular tachyarrhythmias (67 episodes) were detected and appropriately treated in 7.6% of patients. Conclusion: This dual-chamber ICD appears to be safe and well tolerated in patients with drug-refractory symptomatic atrial tachyarrhythmias. The devi ce, used in combination with drugs, effectively treats atrial tachyarrhythm ias with pacing and/or shock therapies and decreases the median episode dur ation. In addition, the device protects from ventricular tachyarrhythmias i n patients with AF and structural heart disease.