Brugada syndrome

Abstract

A male aged 38 years was admitted in Coronary Care Unit within half an hour of a transient blackout preceded by vomiting. There was a similar episode 4 days before, no chest pain or palpitations. His father had died suddenly at the age of 40, after severe chest pain and sweating. Mother and two other siblings were asymptomatic. Clinical examination revealed a pulse of 50/min, regular blood pressure of 140/80 mm of Hg, respiratory rate 14/ min. Systemic examination was normal. ECG showed sinus bradycardia with a pattern of RBBB and saddlebacktype of ST elevation in V 1 -V 3 , diagnostic of the Brugada syndrome ( Fig. 1). Although acute myocardial infarction was never the first possibility, he was given thrombolytic therapy to give him benefit of remote doubt. Cardiac enzymes and tropT were not elevated. Biochemical investigations were normal. The ECG remained unchanged. There were no cardiac arrhythmias on Holter monitoring. His 2D echocardiogram and coronary angiography were normal. On electrophysiological studies, repeated extra stimulus did not induce ventricular tachycardia (VT).The Brugada syndrome has gained wide recognition throughout the world, and today is believed to be responsible for 4-12% of all sudden deaths and approximately 20% of deaths in patients with structurally normal hearts [1]. Brugada and Brugada are to be credited for recognizing a distinct subgroup of patients with idiopathic ventricular fibrillation [2]. It is autosomal dominantly inherited and is caused by mutations in the cardiac sodium channel gene SCN5A [3]. While the mutations are on the same gene as that responsible for the one form of long QT Syndrome (LQT3), the site of mutation is different and does not result in a prolonged QT interval [4]. Ravina et al.[5] reported a case of an 8-year-old boy with an LQT3 ECG pattern. There was a 2:1 AV Block with RBBB in the conducted beats. The QT interval was prolonged (520 ms) with an isoelectric ST segment and a delayed onset T wave pattern. Patient with LQT3 syndrome have a smaller number of cardiac events than patients than with LQT1 or LQT2 do, but when they occur, they are more severe.Patients of the Brugada syndrome are electrocardiographically characterized by the presence of the RBBB pattern or J wave and right precordial ST segment elevation z0.1 mV [2]. However, other conditions like isolated RV infarction and dilated cardiomyopathy should be ruled out before labelling it as the Brugada syndrome. Hsu et al. [6] have reported a case with Brugada-type ECG abnormalities and recurrent VT. Subsequent investigations confirmed the diagnosis of RVMI. Conduction abnormalities are frequently seen in RVMI, the most common being RBBB and complete heart block. In the presence of RBBB and ST elevation with an initial presentation of VT/ventricular fibrillation (VF), ECG in RVMI can be mistaken for the Brugada syndrome. However in RVMI, VT/VF can be induced only during a well defined initial postinfarct period. In Hsu's patient, the electrophysiologic study, 5 days after admission