Relationship between oral amiodarone and inappropriate therapy from an implantable cardioverter defibrillator.

Background: This study evaluated the efficacy of amiodarone for avoiding inappropriate therapies by implantable cardioverter defibrillators (ICDs).

Methods And Results: A total of 232 patients with structural heart disease (58+/-13 years; 78% males) who underwent an initial ICD implantation were retrospectively investigated to compare baseline characteristics and event rates of inappropriate ICD therapy delivery between patients with oral amiodarone therapy (amiodarone group, n=116) and those without (non-amiodarone group, n=116). During a mean follow-up of 29+/-21 months, inappropriate therapies occurred less frequently in the amiodarone group than in the non-amiodarone group (12% vs 27%, P=0.0068). As a cause of inappropriate ICD therapy, only atrial fibrillation (AF) significantly differed between the groups (3% vs 12%, P=0.01). The results of multivariate logistic regression analysis showed that amiodarone therapy (odds ratio (OR) 0.38, 95% confidence interval (CI) 0.19-0.77, P=0.0073) and no history of spontaneous AF (OR 0.27, 95%CI 0.13-0.57, P=0.0007) were independent predictors of a lower risk of inappropriate ICD therapy.

Conclusions: In the present group of ICD patients with structural heart disease, inappropriate therapy delivery occurred predominantly in those with spontaneous AF and/or without amiodarone.