Paced ventricular electrogram fractionation and sudden death in hypertrophic cardiomyopathy and other non-coronary heart diseases.

Abstract

Time for primary review 25 days. The prediction of sudden arrhythmic death (SCD) in patients with non-coronary heart disease has become increasingly important because of the need to select high risk patients who require prophylactic implantable cardioverter-defibrillators (ICD). Hypertrophic cardiomyopathy (HCM) is an important cause of SCD, and while it is clear that ICDs are effective in aborting SCD due to ventricular fibrillation [1–3], there is no generally accepted method of risk stratification to allow large-scale, selective ICD implantation in such patients [4]. This article reviews the various trials which have been performed to predict SCD in patients with HCM. Then an emerging technique which was initially developed for HCM, paced electrogram fractionation analysis (PEFA), is reviewed. This technique is based on detection of the substrate for VF and has promise in identifying high risk patients with HCM and other non-coronary heart diseases which cause SCD. Finally, preliminary results obtained in man and animal models are compared suggesting that PEFA may be used to interpret electrophysiological data from humans at risk of SCD in the context of animal experiments. A useful ‘test’ for predicting SCD must have high enough accuracy to persuade physicians to treat their patients either with or without ICDs on the basis of its results. The definition of a good test depends on the perceived risk/benefit ratio of ICDs in HCM and so the minimum required predictive accuracy of the test will vary amongst physicians. As there is no consensus on the criteria for ICD implantation, we hope to achieve a positive predictive accuracy (PPA) of 0.3 so that three out of every ten patients implanted with an ICD would develop VF. The relatively low SCD rate in HCM causes problems in designing a trial to establish the SCD rate or the PPA of a … * Corresponding author. Tel.: +44-1480-830-541, ext. 4189; fax: +44-1480-831-819