P1594Risk stratification in Brugada syndrome: The role of electrophysiological study

Brugada syndrome (BrS) is a hereditable syndrome, first reported in 1992, characterized by right bundle branch block and an uncommon form of ST-T wave elevation in the V1 and V2 leads and associated with risk of sudden cardiac death (SCD) arising from polymorphic ventricular tachyarrhythmias. BrS is an autosomal dominant inherited condition; however, more than 50% of BrS cases may be sporadic. Approximately 20% to 25% of BrS cases originate from loss of function mutations in the SCN5A cardiac sodium channel.The diagnosis of BrS is mainly based on electrocardiogram. SCD due to ventricular fibrillation can be the first clinical presentation of BrS. The insertion of an implantable cardioverter-defibrillator remains the only approved effective measure to prevent SCD in BrS patients. Risk stratification in BrS is still challenging. Because the role of electrophysiological study (EPS) for estimating prognosis in BrS patients has been controversial, but the expert consensus published in 2013 (Priori et al, 2013) considered the performance of EPS, class IIb. Future randomized studies focused on risk stratification and the value of radiofrequency ablation in BrS patients are needed.This review provides a succinct general overview of BrS focusing on current practices in diagnosis, prognosis, and treatment.

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Novel SCN5A p.Val1667Asp Missense Variant Segregation and Characterization in a Family with Severe Brugada Syndrome and Multiple Sudden Deaths

International Journal of Molecular Sciences ◽

10.3390/ijms22094700 ◽

2021 ◽

Vol 22 (9) ◽

pp. 4700

Author(s):

Michelle M. Monasky ◽

Emanuele Micaglio ◽

Giuseppe Ciconte ◽

Ilaria Rivolta ◽

Valeria Borrelli ◽

...

Keyword(s):

Genetic Testing ◽

Family History ◽

Risk Stratification ◽

Brugada Syndrome ◽

Electrophysiological Study ◽

Functional Characterization ◽

The Family ◽

Novel Variant ◽

History Of ◽

Scn5a Gene

Genetic testing in Brugada syndrome (BrS) is still not considered to be useful for clinical management of patients in the majority of cases, due to the current lack of understanding about the effect of specific variants. Additionally, family history of sudden death is generally not considered useful for arrhythmic risk stratification. We sought to demonstrate the usefulness of genetic testing and family history in diagnosis and risk stratification. The family history was collected for a proband who presented with a personal history of aborted cardiac arrest and in whom a novel variant in the SCN5A gene was found. Living family members underwent ajmaline testing, electrophysiological study, and genetic testing to determine genotype-phenotype segregation, if any. Patch-clamp experiments on transfected human embryonic kidney 293 cells enabled the functional characterization of the SCN5A novel variant in vitro. In this study, we provide crucial human data on the novel heterozygous variant NM_198056.2:c.5000T>A (p.Val1667Asp) in the SCN5A gene, and demonstrate its segregation with a severe form of BrS and multiple sudden deaths. Functional data revealed a loss of function of the protein affected by the variant. These results provide the first disease association with this variant and demonstrate the usefulness of genetic testing for diagnosis and risk stratification in certain patients. This study also demonstrates the usefulness of collecting the family history, which can assist in understanding the severity of the disease in certain situations and confirm the importance of the functional studies to distinguish between pathogenic mutations and harmless genetic variants.

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