Assessment of markers for identifying patients at risk for life-threatening arrhythmic events in Brugada syndrome

Late Potential in Brugada Syndrome. Introduction: Risk stratification for life-threatening arrhythmic events in Brugada syndrome is not yet established. The aim of the present study was to examine the usefulness of various markers in predicting life-threatening arrhythmic events in the Brugada syndrome. Methods and Results: Forty-six patients with Brugada-type ECGs were categorized into the symptomatic (n = 28) and asymptomatic (n = 18) groups. Statistical analyses were performed with respect to the usefulness of the following markers: SCN5A mutation, pharmacologic challenge, ventricular fibrillation (VF) inducibility by programmed electrical stimulation, and late potential (LP) by signal-averaged ECG (SAECG). Comparison between the two groups revealed a significant difference only in LP positivity (92.6% vs 47.1%, P = 0.0004). The symptomatic group had significantly lower RMS40, longer LAS40, and longer fQRSd compared with the asymptomatic group. A significant difference was noted, especially RMS40. The positive predictive value, negative predictive value, and predictive accuracy when setting a cutoff value of 15 muV were 92.0%, 78.9%, and 86.4%, respectively. Furthermore, patients with an RMS40 value < 15 mu V (n = 25) showed significantly higher rates of VF recurrence compared with patients with an RMS40 value >= 15 mu V (n = 19, P = 0.047). Conclusion: Regarding risk stratification for identifying high-risk patients in Brugada syndrome, only LP by SAECG was shown to be useful, suggesting the importance of RMS40 in predicting the history of life-threatening arrhythmic events and the recurrence of VF.