Arrhythmia Diagnosis Following an ICD Shock: Reply

Abstract

Dr. Levine's comments1 are greatly appreciated. Most modern ICDs have arrhythmia discrimination algorithms that have variable success in withholding inappropriate therapy. It must be borne in mind that enhancing specificity for ventricular arrhythmia detection can entail a loss of sensitivity. Accordingly, all algorithms necessarily err on the side of safety and will withhold therapy for only brief period of time. A persistent high rate will eventually be treated as a ventricular arrhythmia and can result in unnecessary and repetetive shocks. Hence the importance of aggressive management of supraventricular arrhythmias in these patients cannot be overemphasized.