title: Effect of amiodarone and sotalol on ventricular defibrillation threshold: the optimal pharmacological therapy in cardioverter defibrillator patients (OPTIC) trial.
abstract: 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.
  
  
  RESULTS
  The Optimal Pharmacological Therapy in Cardioverter Defibrillator Patients (OPTIC) trial was a randomized clinical trial evaluating the efficacy of amiodarone plus beta-blocker and sotalol versus beta-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 beta-blocker therapy (control group), 35 to amiodarone plus beta-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 beta-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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Medicine, Division of Cardiology, J.W. Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany. Hohnloser@em.uni-frankfurt.de
authors.forename: Stefan H
authors.initials: SH
authors.lastname: Hohnloser
authors.forename: Paul
authors.initials: P
authors.lastname: Dorian
authors.forename: Robin
authors.initials: R
authors.lastname: Roberts
authors.forename: Michael
authors.initials: M
authors.lastname: Gent
authors.forename: Carsten W
authors.initials: CW
authors.lastname: Israel
authors.forename: Eric
authors.initials: E
authors.lastname: Fain
authors.forename: Jean
authors.initials: J
authors.lastname: Champagne
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Connolly
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000368:Aged; D000638:Amiodarone / Q000627:therapeutic use*; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000503:physiopathology; D017298:Bisoprolol / Q000627:therapeutic use; D002227:Carbazoles / Q000627:therapeutic use; D000077261:Carvedilol; D003131:Combined Modality Therapy; D017147:Defibrillators, Implantable; D005260:Female; D006323:Heart Arrest; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000627:therapeutic use; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology; D011412:Propanolamines / Q000627:therapeutic use; D013015:Sotalol / Q000627:therapeutic use*; D014693:Ventricular Fibrillation / Q000188:drug therapy* / Q000601:surgery*; D016277:Ventricular Function, Left
chemical_list: D000319:Adrenergic beta-Antagonists; D000889:Anti-Arrhythmia Agents; D002227:Carbazoles; D011412:Propanolamines; D000077261:Carvedilol; D013015:Sotalol; D008790:Metoprolol; D000638:Amiodarone; D017298:Bisoprolol