Assessment of noninvasive markers in identifying patients at risk in the Brugada syndrome: Insight into risk stratification

OBJECTIVES The aim of this study was to compare the use of various noninvas ive markers for detecting risk of life-threatening arrhythmic events in pat ients with Brugada syndrome. BACKGROUND The role of conduction disturbance in arrhythmogenesis of the sy ndrome is controversial, whereas it is well established that repolarization abnormalities are responsible for arrhythmias. The value of noninvasive ma rkers reflecting conduction or repolarization abnormalities in identifying patients at risk for significant arrhythmias has not been shown. METHODS We assessed late potentials (LP) using signal-averaged electrocardi ography (ECG) microvolt T-wave alternans (TW), and corrected QT-interval di spersion (QTD) in 44 consecutive patients who had ECGs showing a pattern of right bundle branch block and ST-segment elevation in leads V-1 to V-3 but structurally normal hearts. The patients were compared with 30 normal indi viduals, RESULTS Eleven patients were excluded from data analysis because of an abse nce of fee manifestations of Brugada syndrome at the time of the tests. A h istory of life-threatening events defined as syncope and aborted sudden dea th was present in 19 of 33 patients (58%); in 15 of the 19 patients, stimul ation induced ventricular fibrillation or polymorphic ventricular tachycard ia, The LP were present in 24 of 33 patients (73%) TWA were present in 5 of 31 patients (16%) and a QTD >50 ms was present in 9 of 33 patients (27%). The incidence of LP in Brugada patients was significantly (p < 0.0001) high er than in the controls, whereas incidences of TWA and QTD were not signifi cantly different. Multivariate logistic regression analysis revealed that t he presence of LP had the most significant correlation to the occurrence of life-threatening events (p = 0.006). CONCLUSIONS Late potentials are a noninvasive risk stratifier in patients w ith Brugada syndrome. These results may support the idea that conduction di sturbance per se is arrhythmogenic, (J Am Coil Cardiol 2001;37:1628-34) (C) 2001 by the American College of Cardiology.