EP testing does not predict cardiac events in Brugada syndrome

Abstract

m s p A i p p a Brugada syndrome (BrS), a major cause of sudden cardiac death in young apparently healthy individuals, has been the subject of a number of controversies ever since its first description. These controversies include its pathophysiology, the causal role of sodium channel mutations, the rognosis of asymptomatic individuals, and the role of programmed electrical stimulation (PES) in risk stratification. The latter topic is the subject of this HeartRhythm controversy. Attempts to use PES in risk stratification strategies (ie, predicting future events) have been performed in patients with all kinds of heart diseases, ranging from ischemic heart disease, arrhythmogenic right ventricular dysplasia, hypertrophic cardiomyopathy, and primary electrical diseases. Whereas in ischemic heart disease (postmyocardial infarction) inducibility seems to identify patients at higher risk (albeit without sufficient negative predictive value), in ther disease entities PES has not stood its initial promising otential to identify patients at risk. A reproducible finding in BrS, reported in several series nd also apparent in meta-analyses, is that patients presenting with cardiac arrest have significantly higher inducibility rates than those studied in the absence of symptoms. This finding in itself does suggest that electrophysiologic (EP) studies do have some diagnostic value. The question then becomes whether the prognostic value of EP studies is sufficiently robust to allow for clinical decision-making, and the answer is No! Potential reasons include the large number of PES variables that impact on its outcome, including the number of extrastimuli (two or three), the minimum coupling interval used (usually values 200 ms or up to refractoriness), the site of stimulation [right ventricular apex (RVA) and/or right ventricular outflow tract (RVOT)], and the amplitude