A 35-year effective treatment of catecholaminergic polymorphic ventricular tachycardia with propafenone

A novel RyR2 mutation associated with co-morbid catecholaminergic polymorphic ventricular tachycardia (CPVT) and benign epilepsy with centrotemporal spikes (BECTS)

In this case report, we describe a 14-year-old patient with a novel RyR2 gene mutation (c.6577G > T/p.Val2193Leu), identified through a comprehensive review of medical history, examination findings, and follow-up data. The pathogenic potential of this mutation, which results in the loss of some interatomic forces and compromises the closure of the RyR2 protein pore leading to calcium leakage, was analyzed using the I-TASSER Suite to predict the structural changes in the protein. This mutation manifested clinically as co-morbid catecholaminergic polymorphic ventricular tachycardia (CPVT) and benign epilepsy with centrotemporal spikes (BECTS), a combination not previously documented in the same patient. While seizures were successfully managed with levetiracetam, the patient's exercise-induced syncope episodes could not be controlled with metoprolol, highlighting the complexity and challenge in managing CPVT associated with this novel RyR2 variation.

Long-term clinical course of patients with catecholaminergic polymorphic ventricular tachycardia: A more than 10-year follow-up cohort study

Background

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited disorder characterized by ventricular arrhythmias induced by physical or emotional stress. Currently, there are limited data available on the long-term prognosis of CPVT.

Methods and Results

In this study, which included both retrospective and prospective components, 12 patients with CPVT (7 males and 5 females) under 18 years old were enrolled to gather and evaluate demographic, clinical, and genetic data. The mean age at diagnosis onset was 7.0 ± 3.1 years. All patients experienced syncope. The mean follow-up duration was 20.1 years. During the follow-up period, all patients experienced at least one episode of supraventricular tachycardia (SVT). Despite beta-blocker therapy, nine patients experienced syncope (75%), and four patients were noncompliant with their treatment. An implantable cardiac defibrillator (ICD) implantation was performed in 10 patients (83%), and among those 5 (50%) experienced appropriate shocks. Inappropriate shocks were observed in all patients with an ICD. The left cardiac sympathetic denervation was performed in 6 patients (50%). One patient died during the follow-up period. Genetic testing was performed in eight patients, five of whom had RYR2 mutations, one patient had mutations in CASQ2, one in TECRL, and one was gene-elusive.

Conclusions

The prevalence of cardiac events, even after the initiation of beta-blocker therapy, was found to be distressingly high during long-term follow-up. SVT, such as atrial fibrillation, were found to be more common than previously thought. Combination therapy with a beta-blocker and an IC antiarrhythmic drug shows promise. An individualized approach to the selection of treatment strategies is essential.

Catecholaminergic Polymorphic Ventricular Tachycardia: A Review of Therapeutic Strategies

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia syndrome characterized by bidirectional or polymorphic ventricular arrhythmia provoked by exercise or emotion. Most cases are caused by pathogenic variants in the gene encoding the cardiac ryanodine receptor (RYR2). The options for treating patients with CPVT have increased during the years, and evidence suggests that these have led to lower arrhythmic event rates. In addition, numerous potential new therapies are being investigated. In this review, we summarize the state of knowledge on both established and potential future treatment strategies for patients with CPVT and describe our approach to their management.

Molecular and tissue mechanisms of catecholaminergic polymorphic ventricular tachycardia

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a stress-induced cardiac channelopathy that has a high mortality in untreated patients. Our understanding has grown tremendously since CPVT was first described as a clinical syndrome in 1995. It is now established that the deadly arrhythmias are caused by unregulated 'pathological' calcium release from the sarcoplasmic reticulum (SR), the major calcium storage organelle in striated muscle. Important questions remain regarding the molecular mechanisms that are responsible for the pathological calcium release, regarding the tissue origin of the arrhythmic beats that initiate ventricular tachycardia, and regarding optimal therapeutic approaches. At present, mutations in six genes involved in SR calcium release have been identified as the genetic cause of CPVT: RYR2 (encoding ryanodine receptor calcium release channel), CASQ2 (encoding cardiac calsequestrin), TRDN (encoding triadin), CALM1, CALM2 and CALM3 (encoding identical calmodulin protein). Here, we review each CPVT subtype and how CPVT mutations alter protein function, RyR2 calcium release channel regulation, and cellular calcium handling. We then discuss research and hypotheses surrounding the tissue mechanisms underlying CPVT, such as the pathophysiological role of sinus node dysfunction in CPVT, and whether the arrhythmogenic beats originate from the conduction system or the ventricular working myocardium. Finally, we review the treatments that are available for patients with CPVT, their efficacy, and how therapy could be improved in the future.