Noninvasive Risk Stratification for Sudden Death in Patients with Asymptomatic Brugada-Type Electrocardiograms

Abstract

The Brugada-type electrocardiogram (ECG) is much more prevalent than the manifest Brugada syndrome. Although electrophysiologic investigations have been proposed as a risk stratifier, their value is controversial, and alternative techniques may be preferred. Autonomic modulation, particularly high vagal tone, may play an important role for sudden cardiac death (SCD) in Brugada syndrome. We sought a strategy to detect a high-risk group in a follow-up study of patients with a Brugada-type ECG. Of several risk indices, a family history of SCD, syncopal episodes, a spontaneous ECG change, and LPs had significant values associating the endpoints. In multivariate analysis, a spontaneous ECG change had the most significance. Combined assessment of significant indices such as a spontaneous ECG change and LPs obtained higher positive predictive values. Since a spontaneous ECG change is augmented by food intake in Brugada syndrome, a large meal (full stomach) test could be a useful technique for identifying high-risk patients. We have reported full stomach test is more effective than pharmacological challenge test in risk stratification of Brugada syndrome. As regards the detection of LPs, recent studies demonstrated that LPs change dynamically over 24 hours. For the determination of LPs, we should record LPs for 24 hours using a Holter electrocardiogram or other techniques.