Abstract 2639: Assessment of Daily Fluctuations in 12-Lead Electrocardiogram and Signal-Averaged Electrocardiogram at Risk for Life-threatening Arrhythmic Events in Brugada Syndrome
BACKGROUND Risk stratification for life-threatening arrhythmic events in Brugada syndrome is not yet established.
OBJECTIVES To evaluate daily fluctuations in 12-lead ECG and signal-averaged ECG (SAECG) characteristics as risk factors for life-threatening arrhythmic events in Brugada syndrome.
METHODS Fifty patients (mean age 53±18 years, 46 males) with a spontaneous or drug-induced type 1 Brugada ECG (symptomatic: N = 14 and asymptomatic: N = 36) underwent 12-lead ECG and SAECG simultaneously every 3 months at least 5 times. We divided the patients into 2 groups: C group (N = 33); patients with at least one spontaneous type 1 ECG, and S group (N = 17); patients without spontaneous type 1 ECG at any time. We evaluated daily fluctuations in 12-lead ECG and SAECG characteristics and compared them between the 2 groups.
RESULTS The number of symptomatic patients was not significantly different between the 2 groups (N = 9 [27%] in C group vs 5 [29%] in S group, p=NS). The daily fluctuations (the difference between maximum and minimum values) in filtered-QRS (Δf-QRS) and LAS40 (ΔLAS40) were significantly larger in symptomatic patients than in asymptomatic patients, in both groups (Δf-QRS: 20±10 vs 8±4 msec in C group, and 19±7 vs 13±6 msec in S group, p < 0.05; ΔLAS40: 24±8 vs 11±6 msec in C group, and 21±6 vs 15±7 msec in S group, p <0.05, respectively). During a mean follow-up period of 49±22 months, Δf-QRS and ΔLAS40 were significantly larger in patients with recurrence of ventricular fibrillation (VF) than those in patients without recurrence of VF (Δf-QRS: 24±7 vs 16±7 msec, p < 0.05; ΔLAS40: 25±7 vs 20±5 msec, p < 0.05).
CONCLUSIONS Daily fluctuations in SAECG were prominent in symptomatic patients. These fluctuations may be more useful for identifying high-risk patients in Brugada syndrome than spontaneous type 1 ECG. Instability of depolarization may be related to the risk of life-threatening arrhythmic events in Brugada syndrome.