Prediction of ventricular tachyarrhythmia in Brugada syndrome by right ventricular outflow tract conduction delay signs

Background: Brugada syndrome (BrS) is an autosomal dominant disease responsible for sudden cardiac death in young individuals without structural anomalies. The most critical part in the management of this channelopathy is identification of high-risk patients, especially asymptomatic subjects. Prior studies have shown that conduction delay in the right ventricular outflow tract (RVOT) is the main mechanism for developing ventricular tachyarrhythmia (VTA) in BrS patients. The aim of this study was to investigate the significance of electrocardiographic RVOT conduction delay parameters as predictors for development of VTA in patients with BrS. Methods and results: We retrospectively analyzed electrocardiograms obtained from 147 BrS patients (43 +/- 15 years, 65% men) and assessed the following electrocardiographic parameters: (1) Tzou criteria (V1R > 0.15 mV, V6S > 0.15 mV, and V6S: R > 0.2), (2) prominent S wave in lead I, lead II, and lead III, (3) SII > SIII, and (4) prominent Qwave in lead III as possible predictors of VTA occurrences during follow-up. Prominent SI, SII, SIII, SII > SIII, QIII, and + ve Tzou criteria occurred more frequently in patients who either presented with VTA or developed VTA during the followup of 56 (IQR: 40-76) months. SII > SIII has the highest area under the curve for prediction of VTA (AUC: 0.84, sensitivity: 80%, specificity: 89%). Multivariable regression analysis showed that prominent S waves in lead I, SII > SIII and + ve Tzou criteria are independent predictors for VTA in BrS patients. Conclusion: Prominent S in lead I, SII > SIII and + ve Tzou criteria can be used as effective signs for predicting VTA in patients with BrS.