Brugada Syndrome: Clinical Features, Risk Stratification, and Management.

In 1992, the Brugada brothers published a patient series of aborted sudden death, who were successfully resuscitated from ventricular fibrillation (VF). These patients had a characteristic coved ST-segment elevation in the right precordial leads on their 12-lead electrocardiogram with no apparent structural heart abnormality. This disease was referred to as "right bundle branch block, persistent ST-segment elevation, and sudden death syndrome." The term Brugada syndrome (BrS) was first coined for this new arrhythmogenic entity in 1996. BrS is more prevalent in Southeast Asian ethnic groups and was considered a familial disease due to the presence of syncope and/or sudden deaths in several members of the same family, however, the genetic alteration was only noted in 1998. The genetic characterization of BrS has proven to be challenging. The most common and well-established BrS genotype involves loss-of-function mutations in the SCN5A gene, but only represents between 15% and 30% of the diagnosed patients. Patients with BrS can present with a range of symptoms which can include syncope, seizures, and nocturnal agonal breathing due to polymorphic ventricular tachycardia or VF. If these arrhythmias are sustained, sudden cardiac death may result. Despite the significant progress on the understanding of BrS over the last two decades, there remain a number of uncertainties and challenges; we present an update review on the subject.

Epicardial only mapping and ablation of ventricular tachycardia: a case series.

AIMS: Ventricular tachycardia (VT) ablation for ventricular arrhythmias is a validated approach, typically performed endocardially, or combined with an epicardial approach if endocardial ablation failed or in case of non-ischaemic cardiomyopathy. We report our experience with epicardial only procedure in a subset of patients with incessant VT or VT storm. METHODS AND RESULTS: This was a single centre retrospective study. Between 2011 and 2014, all patients referred for VT ablation were reviewed at CHU Bordeaux. All patients with an epicardial only (anterior percutaneous approach) mapping and ablation procedure were included. In total, 296 patients underwent a VT ablation and 4 (all male, 70 ± 7 years, 27 ± 11% left ventricular ejection fraction) of them underwent an epicardial only procedure: two ischaemic patients had an endocardial left ventricular thrombus and incessant VT. One patient post-myocarditis had a failed a previous endocardial procedure without local abnormal ventricular activity (LAVA). The fourth patient had a dilated cardiomyopathy and a complicated epicardial puncture followed by mild continuous bleeding (200 mL) precluding anticoagulation associated with left ventricular endocardial access. Local abnormal ventricular activity elimination was verified only epicardially in all and obtained in two patients and non-inducibility was tested and achieved in the two patients without thrombus. No further complications occurred. After a mean follow-up of 21 ± 12 months, one patient (25%) had recurrence of VT and no patient death was observed. CONCLUSION: Epicardial only ablation seems feasible and effective and useful in a limited subset of patients with incessant VT. However, endpoints are more difficult to evaluate and long-term follow-up is needed.

Noninvasive mapping to guide atrial fibrillation ablation.

Atrial fibrillation (AF) is a dynamic rhythm. Noninvasive mapping overcomes many previous barriers to mapping such a dynamic rhythm, by providing a beat-to-beat, biatrial, panoramic view of the AF process. Catheter ablation of AF drivers guided by noninvasive mapping has yielded promising clinical results and has advanced understanding of the underlying pathophysiologic processes of this common heart rhythm disorder.

Noninvasive mapping of ventricular arrhythmias.

Several decades of research has led to the development of a 252-lead electrocardiogram-based three-dimensional imaging modality to refine noninvasive diagnosis and improve the management of heart rhythm disorders. This article reviews the clinical potential of this noninvasive mapping technique in identifying the sources of electrical disorders and guiding the catheter ablation of ventricular arrhythmias (premature ventricular beats and ventricular tachycardia). The article also briefly refers to the noninvasive electrical imaging of the arrhythmogenic ventricular substrate based on the electrophysiologic characteristics of postinfarction ventricular myocardium.

New strategies for ventricular tachycardia and ventricular fibrillation ablation.

Patients with ventricular tachycardia (VT) and ventricular fibrillation (VF) and no reversible cause are difficult to treat. While implantable defibrillators prolong survival, many patients remain symptomatic due to device shocks and syncope. To address this, there have been recent advances in the catheter ablation of VT and VF. For example, non-invasive imaging has improved arrhythmia substrate characterisation, 3D catheter navigation tools have facilitated mapping of arrhythmia and substrate and ablation catheters have advanced in their ability to deliver effective lesions. However, the long-term success rates of ablation for VT and VF remain modest, with nearly half of treated patients developing recurrence within 2-3 years, and this drives the ongoing innovation in the field. This review focuses on the challenges particular to ablation of life-threatening ventricular arrhythmia, and the strategies that have been recently developed to improve procedural efficacy. Patient sub-groups that illustrate the use of new strategies are described.

History and clinical significance of early repolarization syndrome.

The early repolarization (ER) pattern has historically been regarded as a benign ECG variant. However, in recent years this view has been challenged based on multiple reports linking the ER pattern with an increased risk of sudden cardiac death. The mechanistic basis of ventricular arrhythmogenesis in ER syndrome is presently incompletely understood. Furthermore, strategies for risk stratification and therapy for ER syndrome remain suboptimal. The recent emergence of novel mapping techniques for cardiac arrhythmia has ushered a new era of research into the mechanistic basis of ER syndrome. This review provides an overview of current evidence relating to ER and risk of ventricular arrhythmias and discusses potential future areas of research to elucidate the mechanisms of ventricular arrhythmogenesis.

Non Invasive ECG Mapping To Guide Catheter Ablation.

Since more than 100 years, 12-lead electrocardiography (ECG) is the standard-of-care tool, which involves measuring electrical potentials from limited sites on the body surface to diagnose cardiac disorder, its possible mechanism and the likely site of origin. Several decades of research has led to the development of a 252-lead-ECG and CT-scan based, three dimensional, electro-imaging modality to non-invasively map abnormal cardiac rhythms including fibrillation. These maps provide guidance towards ablative therapy and thereby help advance the management of complex heart rhythm disorders. Here, we describe the clinical experience obtained using non-invasive technique in mapping the electrical disorder and guide the catheter ablation of atrial arrhythmias (premature atrial beat, atrial tachycardia, atrial fibrillation), ventricular arrhythmias (premature ventricular beats) and ventricular pre-excitation (Wolff-Parkinson-White syndrome).