Neurally Mediated Susceptibility in Individuals with Brugada‐Type ECG Pattern

BACKGROUND: Neurally mediated syncope and Brugada syndrome (BS) share common pathophysiologic mechanisms related to autonomic nervous system modulations, and particularly with increased vagal tone. This study aimed to investigate the incidence of neurally mediated susceptibility in individuals with Brugada-type electrocardiogram (ECG) pattern. METHODS AND RESULTS: Eight asymptomatic male individuals (mean age 41.6 +/- 10.6 years) with spontaneous or procainamide-induced type 1 ECG pattern of BS and structurally normal hearts underwent a drug-free head-up tilt test. Twenty-five healthy male subjects (mean age 37.4 +/- 14.1 years) with normal ECG and without structural heart disease were included in the study, and served as comparative controls. A positive tilt test response was observed in three out of eight subjects with the Brugada-type ECG pattern (37%) and in three out of 25 controls (12%) (P = 0.018). CONCLUSIONS: This study demonstrates a high incidence of neurally mediated susceptibility in asymptomatic individuals with Brugada-type ECG pattern. Severe diagnostic and therapeutic dilemmas may rise from this coexistence. A positive tilt test in subjects with Brugada-type ECG displaying a history of syncope may mislead the physician to a false sense of security. Further studies are required to validate our findings and possibly evaluate the role of tilt test in risk stratification of patients with BS.