Conduction Delay in Right Ventricle as a Marker for Identifying High‐Risk Patients With Brugada Syndrome

Conduction Delay as a Marker for Brugada Syndrome. Objectives: To evaluate the significance of conduction delay (CD) in the right ventricle (RV) in Brugada syndrome (BS) as a marker for risk stratification of sudden death. Methods: Twenty‐five patients with BS (7 with documented ventricular fibrillation (VF), 8 with syncope, and 10 without symptoms) and 10 control subjects were paced from the RV apex using 8 beats of drive pacing and a single extra‐stimulus. CDs in the right ventricular outflow tract (RVOT) (CD‐RV) and in the lateral left ventricle (L‐LV) (CD‐LV), and the local electrogram durations at a single extra‐stimulus in RVOT (D‐RV) and L‐LV (D‐LV) were calculated. We also evaluated changes in 12‐lead ECG parameters in 16 patients with BS after pilsicainide challenge test (Pilsicainide‐test). Results: Maximal CD‐RV and maximal D‐RV were significantly larger than maximal CD‐LV and maximal D‐LV in BS (26 ± 10 and 105 ± 15 vs 20 ± 6 and 92 ± 15 ms, P < 0.05, respectively). Maximal CD‐RV and maximal D‐RV in patients with documented VF were the largest among the 3 groups. There was a significant positive correlation between maximal CD‐RV or maximal D‐RV and changes in QRS duration in leads V2 and V5 and in S wave duration in lead II and V5 after Pilsicainide‐test (CD‐RV; r = 0.54, 0.51, 0.56, and 0.53: D‐RV; r = 0.55, 0.5, 0.57, and 0.53, P < 0.05, respectively). In control subjects, there were no significant differences. Conclusions: CD in RV was a useful marker for identifying high‐risk patients with BS. CD in the RV, especially in the RVOT epicardium, may be related to arrhythmias in BS. (J Cardiovasc Electrophysiol, Vol. 21, pp. 688‐696, June 2010)