Diagnostic and genetic aspects of the Brugada and other inherited arrhythmias syndromes

Abstract

Doctor Wilde, presenting on behalf of himself and Dr Eckardt, discussed the role of invasive and noninvasive tests for risk stratification of Brugada syndrome. Doctor Hiraoka, presenting on behalf of Y. Yokoyama, M. Takagi, N. Aihara, K. Aonuma, and the Japan Idiopathic Ventricular Fibrillation Study Investigators, further discussed the diagnostic criteria for the Brugada syndrome. Doctor Antzelevitch examined the hypothesis that amplification of spatial dispersion of repolarization in the form of transmural dispersion of repolarization underlies the development of life-threatening ventricular arrhythmias associated with inherited ion channelopathies including the long QT, short QT, and Brugada syndromes. Doctor Corrado discussed the relationship between channelopathies and heart muscle diseases. KeywordsArrhythmia; Sudden cardiac death; Ventricular tachycardia; Fibrillation; Electrophysiology; Channelopathies Role of invasive and noninvasive tests for stratification (A. Wilde and L. Eckardt)Brugada syndrome is increasingly recognized as a disease entity associated with sudden cardiac death (SCD), most often, in relatively young individuals without structural heart disease. The typical ECG is characterized by right precordial ST-segment elevation and discrete prolongation of diverse conduction parameters. Three types of ST-segment elevation are recognized, but only one, type 1 (ie, the 'coved-type' ST segment), is considered to be diagnostic of Brugada syndrome. When a type 1 ECG is associated with documented (or inducible) ventricular arrhythmias, premature SCD or similar ECGs in family members, or nocturnal agonal respiration, Brugada syndrome is diagnosed. 1,2 When the ECG is absent at baseline, drug challenge (iv flecainide, ajmaline procainamide, pilsicainide, or other sodium channel blockers) can unmask the ECG features. A genetic diagnosis can identify 18% to 30% of patients with SCN5A mutations. It is not essential for definitive diagnosis of the syndrome.