Abnormal Atrial Repolarization and Depolarization Contribute to the Inducibility of Atrial Fibrillation in Brugada Syndrome

Abstract

SummaryBrugada syndrome is often accompanied by atrial tachyarrhythmia, such as atrial fibrillation (AF). The aim of this study was to examine atrial vulnerability in patients with Brugada syndrome. Two groups of patients were compared: 18 patients with Brugada syndrome (Brugada syndrome group) and 11 age-matched patients with neither organic heart disease nor AF episodes (control group). Programmed electrical stimulation was performed from the right atrium (RA), and the effective refractory period of the right atrium (ERP-RA), interatrial conduction time (IACT), monophasic action potentials (MAPs) at the high RA, and the inducibility of AF lasting > 30 seconds were studied. MAP duration at 80% repolarization (MAPD 80 ) was calculated. AF was induced with a single extrastimulus or double extrastimuli in all patients with Brugada syndrome but in none of the control patients. The ERP-RA did not differ between the groups. IACT at the shortest diastolic interval was significantly increased in the Brugada syndrome group compared to that in the control group. The maximum slope of the MAPD 80 restitution curve was significantly steeper in the Brugada syndrome group than in the control group (2.4 ± 2.0 versus 0.82 ± 0.36, P < 0.02). Ventricular fibrillation was induced with ventricular programmed stimulation in all Brugada syndrome patients. Both abnormal interatrial conduction and steep restitution of action potential duration may contribute to the atrial arrhythmogenicity in Brugada syndrome. (Int Heart J 2010; 51: 159-165)

Ablation of atrial fibrillation in patients with Brugada syndrome: A systematic review of the literature

“…Previous studies have demonstrated that the index of atrial conduction abnormalities and atrial arrhythmogenesis are substantiated in BS . A shorter action potential duration and steeper restitution curve in the setting of a shorter diastolic interval are observed.…”

Atrial fibrillation in Brugada syndrome: Current perspectives

“…The inducibility of re‐entrant arrhythmias may be dependent on the wavelength of the atrial impulse, considering conduction velocity x refractory period; in particular, when a premature impulse has a short wavelength due to conduction delay or shortened refractoriness, small areas of conduction block may be enough to set up reentrant circuit contributing to the inducibility of AF 57 . These findings may be similar to the pathogenesis of VAs during phase 2 re‐entry.…”

Incidence of Positive Ventricular Late Potentials Differs in Postural Changes among Supine, Left, and Right Lateral Decubitus, and Prone and Sitting Positions in Brugada Syndrome

“…Further data are needed to improve the usefulness of noninvasive prognostic markers for identifying high‐risk patients with BrS. The subjects in our study were ≥ 40 years of age, which might reflect a limited scope of this technique. It has been reported that repolarization and depolarization abnormalities in the ventricle in patients with BrS. Kofune et al reported that abnormal interatrial conduction and steep restitution of action potential duration may contribute to the atrial arrhythmogenicity seen in BrS. Noninvasive repolarization markers such as T‐wave alternans or T‐wave variability and electrophysiological markers such as action potential duration should also be investigated.…”