Is There an Effect of Amiodarone on the Defibrillation Threshold?

The interaction between amiodarone and the defibrillation threshold (DFT) is still controversial. We present a case with dilated cardiomyopathy and recurrent sustained monomorphic ventricular tachycardia who received an automatic implantable cardioverter defibrillator (AICD) while under long-term amiodarone treatment. AICD implantation was performed without thoracotomy. The transvenous lead was inserted via a left subclavian vein puncture and the patch was placed on the lateral chest wall, submuscularly. At the time of implantation a 35J shock was not successful in converting ventricular fibrillation to sinus rhythm, but a 40J rescue shock was successful. After discontinuation of amiodarone, DFT measurements were repeated. Sixteen days later DFT was still higher than 34J, but 71 days later it decreased to 20J.