Risk stratification for asymptomatic patients with Brugada syndrome.

Ventricular fibrillation (VF) is induced in some asymptomatic patients with Brugada syndrome (BS), but the prognostic value of programmed electrical stimulation (PES) in such patients is controversial. The clinical characteristics of 41 asymptomatic BS patients, divided into 2 groups according to whether VF was induced by PES (inducible VF group: n=13, non-inducible VF group: n=28) were evaluated. ST levels in the right precordial leads were measured before and after administration of pilsicainide and the abnormal late potential (LP) was evaluated on the signal-averaged electrogram. The ST level at V(2) at baseline in the inducible VF group was significantly higher than that in the non-inducible VF group (p<0.05). Pilsicainide induced significant ST segment elevation in both groups and the ST level after pilsicainide in the inducible VF group was higher than that in the non-inducible VF group (p<0.01). LP was more frequent in the inducible VF group than in the non-inducible VF group. The criterion of ST level >0.15 mV at baseline with pilsicainide-induced additional ST elevation >0.10 mV and positive LP showed high sensitivity (92%) and specificity (89%) for detection of PES-induced VF in asymptomatic BS patients.