[Brugada syndrome : Risk stratification and prevention of sudden cardiac death]

More than 30 years of Brugada syndrome: a critical appraisal of achievements and open issues

Over the last three decades, what is referred to as Brugada syndrome (BrS) has developed from a clinical observation of initially a few cases of sudden cardiac death (SCD) in the absence of structural heart disease with ECG signs of "atypical right bundle brunch block" to a predominantly electrocardiographic, and to a lesser extent genetic, diagnosis. Today, BrS is diagnosed in patients without overt structural heart disease and a spontaneous Brugada type 1 ECG pattern regardless of symptoms. The diagnosis of BrS is less clear in those with an only transient or drug-induced type 1 Brugada pattern, but should be considered in the presence of an arrhythmic syncope, family history of BrS, or family history of sudden death. In addition to survived cardiac arrest, syncope is probably the single most decisive risk marker for future arrhythmias. For asymptomatic BrS, risk stratification remains challenging. General recommendations to lower the risk in BrS include avoidance of drugs/agents known to induce and/or increase right precordial ST-segment elevation, including treatment of fever with antipyretic drugs. Several ECG markers that have been associated with an increased risk of SCD have been incorporated into a recently published risk score for BrS. The aim of this article is to provide an overview of the status of risk stratification and to illustrate open issues und gaps in evidence in BrS.

Identification of a novel missense SCN5A mutation in a Chinese Han family with Brugada syndrome

Brugada syndrome is an inherited cardiac arrythmia causes sudden death usually associated with loss-of-function mutations of SCN5A, a gene encodes α subunit of cardiac sodium channel Na_v1.5 which plays key role in cardiac function. SCN5A mutation screen is often applied to diagnosis of Brugada syndrome, while its genetic etiology remains not fully understood. In present study, we performed sequence analysis of SCN5A gene in a Chinese Han family with Brugada syndrome, and found a novel heterozygous mutation (c.4969 C > T, p.Leu1657Phe). Functional electrophysiological study showed that the mutation reduced ∼60% sodium current density and largely reduced Na_v1.5 activation (positively shifted activation curve by 13.93 mV), which are the key features for the pathogenesis of Brugada syndrome. However, the mutation enhanced Na_v1.5 function as it slightly decreased inactivation (positively shifted inactivation curve by 7.4 mV) and accelerated recovery (decreased fast recovery by 1.39 ms). In addition, the mutation acts in a dominant negatively manner as it reduced ∼49% sodium current densities in heterozygous state. In conclusion, the study describes a novel SCN5A mutation of p.Leu1657Phe associated with Brugada syndrome, the mutation reduced current density in a dominant negative manner and altered gating kinetics, which will benefit early clinical diagnosis of Brugada syndrome.

[From premature ventricular complexes to sustained ventricular tachycardia : An overview of innovations in the 2022 ESC Guideline on the therapy of ventricular arrhythmias]

The recent 2022 European Society of Cardiology Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death are an update of the former 2015 European guidelines. With multiple tables, algorithms, and comprehensive integration of underlying study data, the new guideline is a user-oriented reference book for clinical practice that also covers special clinical situations such as cardiac arrhythmias in pregnancy or in the context of sports. Regarding the acute treatment of ventricular arrhythmias, cardioversion is now recommended in case of hemodynamically tolerated arrhythmias. Beyond that, the guideline places special emphasis on the management of the electrical storm. In long-term therapy, recommendations for drug therapy have been aligned with current heart failure guidelines. Catheter ablation of ventricular arrhythmias has gained importance not only for recurrent ventricular tachycardia under chronic amiodarone therapy and as an alternative to implantable cardioverter-defibrillators (ICDs) in selected patients with coronary artery disease, but especially for the treatment of idiopathic premature ventricular contractions and tachycardias. Risk stratification and criteria for primary preventive ICDs are still controversial topics, which are discussed in detail based on the specific disease entities.