Prognostic value of electrophysiologic investigations in Brugada syndrome

Introduction: The prognostic value of electrophysiologic investigations in individuals with Brugada syndrome is unclear. Previous studies failed to de termine its value because of a limited number of patients or lack of events during follow-up. We present data on the prognostic value of electrophysio logic studies in the largest cohort ever collected of patients with Brugada syndrome. Methods and Results: Two hundred fifty-two individuals with an ECG diagnost ic of Brugada syndrome were studied electrophysiologically. The diagnosis w as made because of a classic ECG with a roved-type ST segment elevation in precordial leads V-1 to V-3. Of the 252 individuals, 116 had previously dev eloped spontaneous symptoms (syncope or aborted sudden cardiac death) and 1 36 were asymptomatic at the time of diagnosis. A sustained ventricular arrh ythmia was induced in 130 patients (51%). Symptomatic patients were more fr equently inducible (73%) than asymptomatic individuals (33%) (P=0.0001). Fi fty-two individuals (21%) developed an arrhythmic event during a mean follo w-up of 34 +/- 40 months. Inducibility was a powerful predictor of arrhythm ic events during follow-up both in symptomatic and asymptomatic individuals . Overall accuracy of programmed ventricular stimulation to predict outcome was 67%. Overall accuracy in asymptomatic individuals was 70.5%, with a 99 % negative predictive value. Overall accuracy in symptomatic patients was 6 2%, with only a 4.5% false-negative rate. No significant differences were f ound in the duration of the H-V interval during sinus rhythm between sympto matic or asymptomatic individuals. However, the H-V interval was significan tly longer in the asymptomatic individuals who became symptomatic during fo llow-up compared with those who did not develop symptoms (59 +/-8 msec vs 4 8 +/- 11 msec, respectively; P=0.04). Conclusion: Inducibility of sustained ventricular arrhythmias is a good pre dictor of outcome in Brugada syndrome. In asymptomatic individuals, a prolo nged H-V interval during sinus rhythm is associated with a higher risk of d eveloping arrhythmic events during follow-up. Symptomatic patients require protective treatment even when they are not inducible. Asymptomatic patient s can be reassured if they are noninducible.