Letters Section Editor: Robert M. Golub, MD, Senior Editor.
In Reply: Dr Wase raises the issue of inappropriately delivered ICD shocks. In reviewing all ICD shocks in our trial, those not potentially influenced by antiarrhythmic drugs (ie, due to lead fractures or dislodgements) were rare. Only 1 inappropriate shock was delivered for T-wave oversensing and the rest were delivered for supraventricular tachyarrhythmias (primarily atrial fibrillation). None of the patients in the OPTIC study had hypertrophic cardiomyopathy, a condition in which T-wave oversensing by the ICD is more likely to result in inappropriate shock delivery. We did not enroll patients in our study who presented with arrhythmic storms; these patients usually require antiarrhythmic therapy.
Hohnloser SH, Roberts RS, Fain E, Connolly SJ. Antiarrhythmic Therapy for Prevention of Implantable Cardioverter Defibrillator Shocks—Reply. JAMA. 2006;296(10):1229-1230. doi:10.1001/jama.296.10.1230-a