Noninvasive risk stratification of subjects with a Brugada-type electrocardiogram and no history of cardiac arrest

Abstract

Background: Recent studies suggest that the Brugada-type electrocardiogram (ECG) is much more prevalent than the manifest Brugada syndrome. Although invasive electrophysiologic investigations have been proposed as a risk stratifier, their value is controversial, and alternative noninvasive techniques may be preferred. We sought a noninvasive strategy to detect a high-risk group in a long-term follow-up study of subjects with a Brugada-type ECG, and no history of cardiac arrest.

Methods: This study enrolled 124 consecutive subjects with a Brugada-type ECG. Prognostic indices included: age, sex, a family history of sudden death, syncopal episodes, a spontaneous coved-type ST-segment elevation, maximal magnitude of ST-segment elevation, a spontaneous change in ST segment, a mean QRS duration, maximal QT interval, QT dispersion, late potentials (LP) by signal-averaged ECG, and microvolt T-wave alternans.

Results: Of the 124 subjects, 20 consenting subjects had an implantable defibrillator before follow-up. During a 40 +/- 19-month follow-up, 12 subjects (9.7%) reached one of the endpoints (sudden death or ventricular tachyarrhythmia). Of the 12 risk indices, a family history of sudden death, syncopal episodes, a spontaneous coved-type ST-segment elevation, a spontaneous change in ST segment, and LP had significant values. In multivariate analysis, a spontaneous change in ST segment had the most significance (a relative hazard, 9.2; P = 0.036). Combined assessment of this index and other significant indices obtained higher positive predictive values (43-71%).

Conclusions: A spontaneous change in ST segment is associated with the highest risk for subsequent events in subjects with a Brugada-type ECG. The presence of syncopal episodes, a history of familial sudden death, and/or LP may increase its value.

Figure 1

Twelve‐lead ECG showing a Brugada‐type ECG of coved type.

Figure 2

A spontaneous change of ST segment consistent with the Brugada syndrome in ECG leads V₁–V₃ taken on July 22, 1999.

Figure 3

Kaplan–Meier event‐free curves of a spontaneous ST‐segment change.

Figure 4

Kaplan–Meier event‐free curves for combined assessment of a spontaneous ST‐segment change and a family history of sudden death (A), and combined assessment of a spontaneous ST‐segment change and late potentials (B).