The Use of Dual Chamber ICD With Special Programmed Features to Lower the Risk of Inappropriate Shock

While implantable cardioverter-defibrillator (ICD) therapy has become the gold standard for sudden death prevention in high risk individuals, reduction of device associated morbidity remains a significant problem. Rapidly conducted atrial tachyarrhythmias inappropriately detected as ventricular tachycardia (VT) are the most common cause for inappropriate shocks in ICD recipients, affecting 10 to 40% of patients. Large multicenter trials have shown modest benefits of atrial pacing in preventing atrial fibrillation, however right ventricular (RV) pacing was not limited, thus any favorable effects associated with atrial prevention and treatment may have been offset by the RV pacing. New algorithms to prevent RV pacing are now made available in our current devices. The choice of dual chamber versus single chamber ICD for primary prevention warrants re-assessment of atrial prevention and termination therapies, without the potentially adverse effects of RV pacing. This Multi Center Pilot study will enroll 100 eligible subjects, 50 to single chamber and 50 to dual chamber ICDs. Patients will be followed for one year.