Prevalence of type–1 Brugada electrocardiogram (ECG) pattern (BrP), an inherited arrhythmic disease associated with sudden cardiac death, is higher in the central region of Thailand than in other Asian countries, according to a research letter published March 6 in the Journal of the American College of Cardiology.

The Brugada ECG pattern BrP is characterized by coved type (type–1 BrP) ST segment elevation greater than or equal to 2 mm in right precordial leads and saddleback type (type–2 BrP). The clinical manifestations of Brugada syndrome vary and include ventricular fibrillation, ventricular tachycardia, sudden cardiac death, syncope, nocturnal agonal respiration, palpitations, or chest pain.

Iris M. van Hagen, MD, et al., evaluated the prevalence of BrP in Thailand from the Electricity Generating Authority of Thailand study, a population–based longitudinal cohort study to identify cardiovascular risk factors in Thailand.

Baseline and follow–up ECGs from patients enrolled in the study from 2009 – 2014 were retrospectively analyzed, and basic characteristics were compared between type–1 BrP, type–2 BrP and non–BrP subjects.

The study group consisted of 2,446 subjects, 10 of whom were diagnosed with type–1 BrP; 21 subjects had type–2 BrP. In males, the prevalence of type–1 BrP and type–2 BrP were 0.55 percent and 0.83 percent, respectively. Hypertension was more common in type–1 BrP subjects. There were no documented episodes of ventricular fibrillation, ventricular tachycardia, sudden cardiac death, or deaths in either the type–1 or type–2 BrP groups after five years. Interestingly, 11 more subjects were later identified with a type–1 BrP at the five–year follow–up visit.

Researchers addressed the study’s limitations saying, “By using a retrospective ECG database, we were unable to diagnose individuals with definitive Brugada syndrome since genetics, electrophysiology studies, and drug provocation tests could not be performed. We also do not have imaging such as echocardiography to rule out structural heart disease.”

Moving forward, van Hagen, et al., encourage exploring larger multicenter studies of prevalence, ECG screening, risk stratification and management of type–1 BrP.