Prevalence of asymptomatic ST segment elevation in right precordial leads with right bundle branch block (Brugada-type ST shift) among the general Japanese population

Abstract

Objective-To examine the modality and morbidity of asymptomatic ST segment elevation in leads V1 to V3 with right bundle branch block (Brugada-type ST shift). Methods-8612 Japanese subjects (5987 men and 2625 women, mean age 49.2 years) who underwent a health check up in 1997 were investigated. Those with Brugada-type ST shift underwent the following further examinations over a two year period after the initial check up: ECG, echocardiogram, 24 hour Holter monitoring, treadmill exercise testing, signal averaged ECG, and slow kinetic sodium channel blocker loading test (cibenzoline, 1.4 mg/kg). Results-Asymptomatic Brugada-type ST shift was found in 12 of 8612 (0.14%) subjects. Eleven of these 12 subjects were followed up. Follow up ECG exhibited persistent Brugada-type ST shift in seven of 11 (63.6%) subjects. ST shift was transformed from a saddle back to a coved type in three subjects. None of the subjects had morphological abnormalities or abnormal tachyarrhythmias. Positive late potentials were found in seven of 11 (63.6%) subjects. Augmentation of ST shift was shown by both submaximal exercise and drug administration in one of the 11 subjects (9.1%). Conclusions-Asymptomatic subjects with Brugada-type ST shift were not unusual, at a rate of 0.14% in the general Japanese population. Almost all of the subjects had some abnormalities in non-invasive secondary examinations. Additional and prospective studies are needed to confirm the clinical significance and the prognosis of asymptomatic Brugada-type ST shift. (Heart 2001;86:161-166) Keywords: Brugada syndrome; signal averaged electrocardiogram; sodium channel blocker; sudden death Since Brugada and Brugada 1 first described eight cases of characteristic ECG features consisting of right bundle branch block (RBBB) and persistent ST segment elevation in leads V1 to V3 (Brugada-type ST shift) associated with aborted cardiac sudden death without structural heart diseases, clinical evidence of a link between Brugada-type ST shift and cardiac sudden death has been accumulating. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Because of increasing awareness of this evidence, a Brugada-type ST shift is being discovered incidentally in more and more asymptomatic subjects. Some recent reports describe Brugada-type ST shift recognised in asymptomatic subjects.5 15 However, the clinical significance of Brugada-type ST shift in asymptomatic subjects is unclear. Therefore, it is still not known whether a Brugada-type ST shift is a specific indicator of ventricular fibrillation or a life threatening sign of sudden cardiac death.On the basis of these speculations, we investigated the prevalence of asymptomatic Brugada-type ST shift in the general Japanese population and performed secondary cardiovascular examinations focusing on latent myocardial involvement in the screened subjects. Methods STUDY POPULATIONThe study population consisted of 8612 adult Japanese subjects (5987 men and 2625 women) ranging in age from 22-84 years (mean 49.2 years). All...

Long‐Term Prognosis of Brugada‐Type ECG and ECG With Atypical ST‐Segment Elevation in the Right Precordial Leads Over 20 Years: Results From the Circulatory Risk in Communities Study (CIRCS)

“…In keeping with previous reports,4, 7, 9, 10, 21, 22 there was a male predominance among participants with BrS. In the present study, no SCD among participants with type 1 BrS and only 1 SCD among those with non–type 1 BrS was observed during the follow‐up period, which was consistent with previous community‐based studies,6, 8, 9, 12, 14 except for the Atomic Heart Study 11.…”

“…The prevalence of type1 BrS (0.1%) and non–type 1 BrS (1.2%) in this cohort was compatible with that in previous studies: 0.0% to 0.2%5, 6, 7, 8, 9, 10, 12, 13, 14, 19 for type 1 BrS and 0.0% to 6.0% for non–type 1 BrS 4, 5, 7, 9, 10, 13, 14, 20. In keeping with previous reports,4, 7, 9, 10, 21, 22 there was a male predominance among participants with BrS.…”

“…The data from previous studies vary regarding prevalence and prognosis for patients with Brugada‐type ECG (BrS) because of different populations (eg, general population, office workers),4, 5, 6, 7, 8, 9 different ECG definitions,5, 6, 9, 10, 11, 12 relatively short‐term follow‐up,5, 6, 9, 10, 12, 13 or poorly defined SCD 5, 6, 7, 8, 10, 11, 13, 14…”

Frequency of Brugada-Type ECG Pattern (Brugada Sign) in Southern Turkey

“…In a Japanese urban population, the frequency in males was found to be 0.38% for the coved type and 2.14% for the saddleback type. 8) Furuhashi, et al 9) reported the frequency of ST segment elevation as 0.14% in 8612 asymptomatic subjects with a mean age of 49 years. In recent years, the frequency of Brugada sign has been reported to range between 0.14-0.70% in middle-aged healthy populations.…”

Indications for an Implantable Cardioverter Defibrillator (ICD)

“…The indications (primary and secondary prevention) of ICD in specific disorders are shown in Table 2. The prognosis of patients with Brugada syndrome is controversial especially in asymptomatic patients (48)(49)(50). Their prognosis seems good in Japan (51 From Japanese Joint Guidelines of Nonpharmacological Therapy of Cardiac Arrhythmias (34).…”