Type 2 Brugada pattern in healthy individuals linked to high SUD risk
Type 2 Brugada pattern is highly prevalent in healthy Filipinos and is associated with sudden unexplained death (SUD), according to a study.
“The risk [of cardiac events] appears to be considerable even among those with the type 2 [Brugada] pattern, [which is] in contrast to other studies, where the risk appears to be concentrated on the type 1 Brugada [pattern],” said Dr Jaime Alfonso Aherrera from the Department of Medicine, University of the Philippines-Philippine General Hospital, Manila, Philippines.
Using data from the LIFECARE* cohort, researchers reviewed electrocardiogram (ECG) patterns of 3,072 asymptomatic Filipinos aged 20–50 years, 163 (5.3 percent) of whom demonstrated Brugada patterns. The Brugada patterns on ECG were classified into three categories: type 1 (coved ST-elevation ≥2 mm, n=14), type 2 (saddleback ST-elevation ≥1 mm, n=119), and type 3 (either coved or saddleback ST-elevation <1 mm, n=30). [APSC 2017, LBT1)
Brugada patterns were most common among participants aged 40–50 years (41 percent, n=67) and 20–29 years (35 percent, n=57), as well as among current smokers (46 percent, n=75) and alcohol drinkers (77 percent, n=128).
Of the 144 participants followed up at 5 years, 24 experienced cardiac events (syncope, presyncope, and sudden death). Of the 24 individuals, three had Brugada 1, 15 had Brugada 2, and six had Brugada 3 patterns.
All six SUDS occurred in those with Brugada 2 pattern. This high mortality rate is a ‘worrisome finding’, said Aherrera.
He attributed the high prevalence of type 2 Brugada pattern in the Philippines to the warmer environment, as well as the higher alcohol intake, and unknown genetic factors among Filipinos.
“This study ... suggests that a type 2 Brugada pattern may not be as benign as previously suspected,” commented Dr Hugh Calkins from The Johns Hopkins Hospital, Baltimore, Maryland, US.
“Further research is needed to determine if widespread screening should be advised ... But at the very least, physicians need to be aware that an ECG should be obtained in all syncope patients with a specific focus on whether they have a Brugada pattern,” Calkins added.
*LIFECARE: LIFE course study in CARdiovascular disease Epidemiology