Shocks from pacemaker cardioverter defibrillators increase with amiodarone in patients at high risk for sudden cardiac death

The efficacy of amiodarone used in combination with a pacemaker cardioverter defibrillator (PCD) to decrease episodes of ventricular tachycardia and subsequent PCD shocks is not clear. We examined a retrospective registry of 82 patients with PCD implantation to define the efficacy of amiodarone treatment. We compared patients treated with amiodarone ( for 24 consecutive months without interruption) versus no amiodarone. In patients treated with amiodarone there was a 3-fold increase (p = 0.02) in PCD shocks; in patients not on beta-blockers, amiodarone resulted in a 6-fold increase (p < 0.05) in PCD shocks. Patients with a left ventricular ejection fraction >30% on amiodarone and patients <72 years old had increases (p < 0.05) in PCD shocks. In conclusion, patients treated with amiodarone had more PCD shocks than those not treated. These findings are unexpected and merit a prospective study. Copyright (C) 2003 S. Karger AG, Basel.