Published Online
on July 3, 2006

A more recent version of this article appeared on July 11, 2006

This Article Full Text (PDF) All Versions of this Article: 114/2/104    most recent CIRCULATIONAHA.106.618421v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hohnloser, S. H. Articles by Connolly, S. J. Search for Related Content PubMed PubMed Citation Articles by Hohnloser, S. H. Articles by Connolly, S. J. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Hazardous Substances DB AMIODARONE HYDROCHLORIDE CARVEDILOL METOPROLOL Medline Plus Health Information Pacemakers and Implantable Defibrillators Related Collections Hypertrophy Ablation/ICD/surgery

Submitted on February 3, 2006
Revised on April 26, 2006
Accepted on April 28, 2006

Effect of Amiodarone and Sotalol on Ventricular Defibrillation Threshold. The Optimal Pharmacological Therapy in Cardioverter Defibrillator Patients (OPTIC) Trial

Stefan H. Hohnloser MD^*, Paul Dorian MD, Robin Roberts MTech, Michael Gent MSc, Carsten W. Israel MD, Eric Fain MD, Jean Champagne MD, and Stuart J. Connolly MD

From the Department of Medicine, J.W. Goethe University (S.H.H., C.W.I.), Frankfurt, Germany; Department of Medicine, University of Toronto (P.D.), Toronto, Ontario, Canada; Department of Clinical Epidemiology and Biostatistics (R.R., M.G.) and Department of Medicine (S.J.C.), McMaster University, Hamilton, Ontario, Canada; St Jude Medical (E.F.), Sunnyvale, Calif; and Department of Medicine, University de Laval (J.C.), Quebec City, Quebec, Canada.

^* To whom correspondence should be addressed. E-mail: Hohnloser{at}em.uni-frankfurt.de.

Background--Many patients with implanted cardioverter defibrillators (ICDs) receive adjunctive antiarrhythmic drug therapy, most commonly amiodarone or sotalol. The effects of these drugs on defibrillation energy requirements have not been previously assessed in a randomized controlled trial.

Methods and Results--The Optimal Pharmacological Therapy in Cardioverter Defibrillator Patients (OPTIC) trial was a randomized clinical trial evaluating the efficacy of amiodarone plus -blocker and sotalol versus -blocker alone for reduction of ICD shocks. Within OPTIC, a prospectively designed substudy evaluated the effects of the 3 treatment arms on defibrillation energy requirements. Defibrillation thresholds (DFTs) were measured (binary step-down protocol) at baseline and again after 8 to 12 weeks of therapy in 94 patients, of whom 29 were randomized to receive -blocker therapy (control group), 35 to amiodarone plus -blocker, and 30 to sotalol. In the control group, the mean DFT decreased from 8.77±5.15 J at baseline to 7.13±3.43 J (P=0.027); in the amiodarone group, DFT increased from 8.53±4.29 to 9.82±5.84 J (P=0.091). In the sotalol group, DFT decreased from 8.09±4.81 to 7.20±5.30 J (P=0.21). DFT changes in the -blocker and the amiodarone group were significantly different (P=0.006). In all patients, adequate safety margins for defibrillation were maintained. No clinical variable predicted baseline DFT or changes in DFT on therapy.

Conclusion--Although amiodarone increased DFT, the effect size with modern ICD systems is very small. Therefore, DFT reassessment after the institution of antiarrhythmic drug therapy with amiodarone or sotalol is not routinely required.

Key words: defibrillation • antiarrhythmia agents • tachyarrhythmias

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