Letters Section Editor: Robert M. Golub, MD, Senior Editor.
To the Editor: Dr Connolly and colleagues1 concluded that antiarrhythmic therapy reduces the frequency of shock delivery in patients with an ICD. However, 3 different β-blockers were used and, among them, carvedilol has greater antiarrhythmic potential than either metoprolol or bisoprolol.2 Furthermore, the authors did not provide information on any concomitant medication use. This limits the evaluation of the data because the patient cohort presented with left ventricular systolic dysfunction, mainly ischemic, and several drugs normally administered in this situation affect disease manifestation. Angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, potassium-sparing agents, statins, omega-3 fatty acids, and aspirin possess antiarrhythmic properties,3 while other medications, such as diuretics4 and digoxin,5 may be proarrhythmic. Appropriate selection of agents that may be antiarrhythmic, coupled with cautious usage of those agents that may be proarrhythmic, should be attempted as a first-line therapy before subjecting patients with ICDs to specific antiarrhythmic treatment with its potential adverse effects.
Coceani M. Antiarrhythmic Therapy for Prevention of Implantable Cardioverter Defibrillator Shocks. JAMA. 2006;296(10):1229-1230. doi:10.1001/jama.296.10.1229-b