Brugada Syndrome Behind Complete Right Bundle-Branch Block

Aizawa, Yoshifusa; Takatsuki, Seiji; Sano, Motoaki; Kimura, Tokuhiro; Nishiyama, Nobuhiro; Fukumoto, Kotaro; Tanimoto, Yoko; Tanimoto, Kojiro; Murata, Mitsushige; Kubo, Takashi; Mitamura, Hideo; Ogawa, Satoshi; Funazaki, Toshikazu; Sato, Masahito; Fukuda, Keiichi

doi:10.1161/circulationaha.113.003472

Cited by 30 publications

(24 citation statements)

References 32 publications

(36 reference statements)

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“…SCN10A -S1337T and R1869C were found in 2 AF probands with BrS phenotypes. The SCN10A -N1715 mutant carrier presented with BrS and RBBB ECG pattern, an overlapping phenotype recently highlighted by Aizawa et al (26). (Fig.…”

Section: Resultsmentioning

confidence: 65%

Mutations in SCN10A Are Responsible for a Large Fraction of Cases of Brugada Syndrome

Barajas-Martínez

Pfeiffer

et al. 2014

Journal of the American College of Cardiology

217

157

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Objectives The purpose of this study was to test the hypothesis that SCN10A variants contribute to the development of Brugada syndrome (BrS). Background BrS is an inherited sudden cardiac death syndrome. Fewer than 35% of BrS probands have genetically identified pathogenic variants. Recent evidence has implicated SCN10A, a neuronal sodium channel gene encoding Nav1.8 in the electrical function of the heart. Methods Clinical analysis and direct sequencing of BrS-susceptibility genes were performed on 150 probands, family members and >200 healthy controls. Expression and co-immunoprecipitation studies were performed to functionally characterize the putative pathogenic mutations. Results We identified 17 SCN10A mutations in 25 probands (20 M/5 F); 23 of the 25 (92.0%) displayed overlapping phenotypes. SCN10A mutations were found in 16.7% of BrS probands, approaching our yield for SCN5A mutations (20.1%). BrS patients with SCN10A mutations were more symptomatic and displayed significantly longer PR and QRS intervals than SCN10A negative BrS probands. The majority of mutations localized to the transmembrane-spanning regions. Heterologous co-expression of wild-type (WT) SCN10A with WT-SCN5A in HEK cells caused a near doubling of sodium channel current (INa) compared with WT-SCN5A alone. In contrast, co-expression of SCN10A mutants (R14L and R1268Q) with WT-SCN5A caused a 79.4% and 84.4% reduction in INa, respectively. Co-immunoprecipitation studies performed provide evidence for co-association of Nav1.8 and Nav1.5 in the plasma membrane. Conclusions Our study identifies SCN10A as a major susceptibility gene for BrS, thus greatly enhancing our ability to genotype and risk stratify probands and family members.

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Section: Resultsmentioning

confidence: 65%

Mutations in SCN10A Are Responsible for a Large Fraction of Cases of Brugada Syndrome

Barajas-Martínez

Pfeiffer

et al. 2014

Journal of the American College of Cardiology

217

157

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“…They reported that type‐1 ECG converted to type‐2, type‐3, or normal ECG after elimination of delayed or fragmented potential with catheter ablation. On the other hand, complete right bundle‐branch block (CRBBB), which also causes delayed activation in the RV, can mask the typical BrS ECG and sometimes make it difficult to diagnose BrS …”

Section: Introductionmentioning

confidence: 99%

Impact of premature activation of the right ventricle with programmed stimulation in Brugada syndrome

Nakagawa

Nagase

Morita

et al. 2017

Cardiovasc electrophysiol

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Background: In Brugada syndrome (BrS), it has been reported that delayed activation in the RV is related to the development of type-1 ECG, which is more critical than type-2. On the other hand, the coexistence of complete right bundle-branch block (CRBBB), which also causes delayed activation in the RV, sometimes makes typical BrS ECG misleading. We hypothesized that premature stimulation of the RV can unmask the influence of delayed activation in the RV and convert the morphology of ECG in BrS patients. Methods and results:In 35 BrS patients with type-1 ECG including 8 patients with concomitant CRBBB and 6 control subjects with CRBBB, progressively premature single stimulations were delivered from the RV apex on electrophysiological study. Then we evaluated QRS morphology of fusion beats created by single premature stimulation in each patient. In 29 (83%) of 35 of the BrS patients, conversion from type-1 to type-2 ECG was observed during the process of single premature stimulation. Additionally, in all 8 BrS patients with concomitant CRBBB, type-1 or type-2 BrS ECG was revealed by premature stimulation with relief of CRBBB. These findings were not observed in any of the control subjects with CRBBB. Conclusion:Single premature stimulation of the RV converts ECG from type-1 to type-2 in most BrS cases and unmasks type-1 ECG in all BrS cases with CRBBB. Our results could suggest that type-1 ECG is associated with delayed activation of the RV compared with type-2 ECG.

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“…[6][7][8] In the present study, a similar procedure was attempted in patients with permanent CRBBB. In an electrophysiology study, 2 catheters were positioned at high right atrium (HRA) and right ventricular apex (RVA).…”

Section: Pacing From the Right Ventricle To Resolve Crbbbmentioning

confidence: 99%

“…6 Cases of BrS masked by CRBBB have been recently reported, 7-9 but the prevalence and clinical significance of BrS masked by CRBBB have not been well studied. The present study is the first to evaluate the prevalence of BrS masked by CRBBB (3.1%).…”

Section: Manifestation Of Brs Masked By Crbbbmentioning

confidence: 99%

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

Nagase

Morita

Nakagawa

et al. 2015

Circ J

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2568WADA T et al. Circulation JournalOfficial Journal of the Japanese Circulation Society http://www. j-circ.or.jp occasionally induces fatal ventricular tachyarrhythmia, SCB test should be avoided in patients with type 1 ECG under baseline conditions, but it is difficult to identify type 1 in BrS patients with CRBBB. The prevalence and clinical significance of the combination of CRBBB and BrS has not been well investigated. Therefore, the present study evaluated the incidence and clinical significance of BrS with CRBBB, especially BrS masked by CRBBB. Methods SubjectsA total of 326 consecutive BrS patients (mean age, 47.4±13.6 years; male, 95.4%) and 20 control subjects were enrolled in this study. All BrS patients were diagnosed as having BrS based on HRS/EHRA/APHRS expert consensus statement. 1 Type 1 ECG was documented spontaneously or was provoked by SCB test (pilsicainide, at a dose of 1 mg/kg for 5-10 min) in all BrS patients. Echocardiography was performed to exclude rugada syndrome (BrS) is characterized by ST-segment elevation at the J point in the right precordial electrocardiographic (ECG) leads and sudden cardiac death caused by polymorphic ventricular tachycardia/ventricular fibrillation (PVT/VF). This ST-segment elevation is the most important characteristic for diagnosis of BrS, 1,2 and spontaneous ST-segment elevation is reported to be a high risk for PVT/VF.

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Brugada Syndrome Behind Complete Right Bundle-Branch Block

Cited by 30 publications

References 32 publications

Mutations in SCN10A Are Responsible for a Large Fraction of Cases of Brugada Syndrome

Mutations in SCN10A Are Responsible for a Large Fraction of Cases of Brugada Syndrome

Impact of premature activation of the right ventricle with programmed stimulation in Brugada syndrome

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

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