Risk Stratification in Patients with Brugada Syndrome in Japanese Multicenter Study: Comparison between Symptomatic and Asymptomatic Patients
Masahiko Takagi, M.D., Ph.D, Yasuhiro Yokoyama, M.D., Kazutaka Aonuma, M.D. ,Ph.D, Naohiko Aihara, M.D., and Masayasu Hiraoka, M.D.,Ph.D.,FAHA.,FACC. for the Japan Idiopathic Ventricular Fibrillation Study Investigators
Risk stratification between symptomatic and asymptomatic patients with Brugada syndrome has been a matter of debates and no firm concensus has been achieved. The aim of the present study is to compare clinical and electrocardiographic (ECG) characteristics between symptomatic and asymptomatic patients with Brugada syndrome to identify a new marker for distinction between high- and low-risk patients.
A total of 173 consecutive patients with Brugada syndrome (53±14 years, 166 males, J wave amplitude >0.2mV and either coved or saddle-back type ST segment elevation in leads V1 and/or V2) were enrolled in the Japan Idiopathic Ventricular Fibrillation Study during February, 2002 and November, 2004. The parameters for clinical and ECG characteristics were evaluated in all the subjects divided into three groups; VF group (VF): patients with aborted sudden death and documented VF (N=22), Syncope group (Sy): patients with syncope without documentation of VF (N=64), and asymptomatic group (AS): patients without symptoms (N=87).
1) There were no significant differences among the 3 groups as to age, gender, family history of sudden cardiac death and/or familiar incidences in Brugada-type ECG signs, and inducibility of sustained ventricular tachyarrhythmias during electrophysiological study. Past history of atrial fibrillation was highest in the VF group (32, 28, 14 % [p=0.04], VF v.s. Sy v.s. As, respectively).
2) The resting 12-lead ECG findings revealed that r-J interval (an interval from QRS onset to J point) in leads V1 and V2 was longest in the VF group (V1: 95±12, 90±15, 86±14 [p=0.008]、V2: 102±16, 96±19, 88±13 msec [p=0.0002], VF v.s. Sy v.s. As, respectively). QRS duration in V6 (102±18, 102±20, 94±11 msec [p=0.007], VF v.s. Sy v.s. As, respectively) was largest in the VF group.
3) During a mean follow-up of 15±5 months, incidences in cardiac events (sudden death and/or VF) were highest in the VF group (25, 12, 0 % [p=0.01], VF v.s. Sy v.s. As, respectively).
Conclusions In symptomatic patients (VF and Sy), prolonged ventricular depolarization in ECG was prominent, especially in the VF group. The markers of depolarization in the precordial leads on the 12-lead ECG may distinguish high-risk from low-risk patients with Brugada syndrome.