Incidence and Clinical Significance of Brugada Syndrome Masked by Complete Right Bundle-Branch Block

Tadashi Wada; Satoshi Nagase; Hiroshi Morita; Koji Nakagawa; Nobuhiro Nishii; Kazufumi Nakamura; Kunihisa Kohno; Hiroshi Ito; Kengo F. Kusano; Tohru Ohe

doi:10.1253/circj.CJ-15-0618

Arrhythmia/Electrophysiology

Incidence and Clinical Significance of Brugada Syndrome Masked by Complete Right Bundle-Branch Block

Tadashi Wada, Satoshi Nagase, Hiroshi Morita, Koji Nakagawa, Nobuhiro Nishii, Kazufumi Nakamura, Kunihisa Kohno, Hiroshi Ito, Kengo F. Kusano, Tohru Ohe

Author information

Tadashi Wada
Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences
Satoshi Nagase
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center
Hiroshi Morita
Department of Cardiovascular Therapeutics, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences
Koji Nakagawa
Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences
Nobuhiro Nishii
Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences
Kazufumi Nakamura
Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences
Kunihisa Kohno
Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences
Hiroshi Ito
Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences
Kengo F. Kusano
Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center
Tohru Ohe
Department of Cardiology, Sakakibara Heart Institute of Okayama

Keywords: Brugada syndrome, Complete right bundle-branch block, Extrastimulus, Ventricular fibrillation

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Supplementary material

2015 Volume 79 Issue 12 Pages 2568-2575

DOI https://doi.org/10.1253/circj.CJ-15-0618

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Abstract

Background:Brugada syndrome (BrS)-type electrocardiogram (ECG) is concealed by complete right bundle-branch block (CRBBB) in some cases of BrS. Clinical significance of BrS masked by CRBBB is not well known.Methods and Results:We reviewed an ECG database of 326 BrS patients who had type 1 ECG with or without pilsicainide. “BrS masked by CRBBB” was defined on ECG as <2-mm elevation of the J point at the time of CRBBB in the right precordial leads, and BrS-type J-point elevation ≥2 mm at the time of normalized QRS complex on relieved CRBBB. We identified 25 BrS patients (7.7%) with persistent (n=12) or intermittent CRBBB (n=13). Relief of CRBBB by pacing was performed in patients with persistent CRBBB. The prevalence of BrS masked by CRBBB was 3.1% (10/326 patients). Three patients had type 1 ECG, and 7 patients had type 2 or 3 ECG on relief of CRBBB. Two of these 10 patients had lethal arrhythmic events during the follow-up period (mean, 86.4±57.2 months). There was no prognostic difference between BrS masked by CRBBB and other BrS.Conclusions:In a small BrS population, CRBBB can completely mask typical BrS-type ECG. BrS masked by CRBBB is associated with the same risk of fatal ventricular tachyarrhythmia as other BrS. (Circ J 2015; 79: 2568–2575)

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