Working Diagnosis:
Catecholaminergic polymorphic ventricular tachycardia (CPVT)

Treatment:
Patient was started on nadolol.

Outcome:
Patient CPVT was controlled on nadolol and he was medically retired.

Author's Comments:
Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a rare arrhythmogenic disorder characterized by adrenergic-induced bidirectional and polymorphic VT. Key features include CPVT reproducibly induced during exercise. CPVT has been identified as a genetic disorder with mutations in the cardiac ryanodine receptor gene (RYR2) or cardiac calsequestrin gene (CASQ2). When left untreated, there is an estimated 4- and 8-year cardiac event rates of 33% and 58% respectively. Beta-blockers without sympathomimetic activity such as nadolol are the first line therapeutic and prophylactic option for patients with CPVT. However, there remains an estimated 8-year cardiac event rate of 27% even on beta-blockers. Second line options include an implantable cardioverter defibrillator, antiarrhythmic agents such as verapamil and flecainide, and left cardiac sympathetic denervation.

Editor's Comments:
Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a primary electrical disease characterized by a normal resting electrocardiogram without any detectable structural abnormalities of the heart. Induction of malignant arrhythmias may be induced during adrenergic stress leading to syncope or sudden cardiac death. CPVT is a rare channelopathy manifested especially in childhood and adolescence. The risk of cardiac events is high. Early identification and risk stratification is of major importance in patients with CPVT. All CPVT patients should have a genetic diagnosis to further assist an individualized treatment plan. In concordance with other cardiac channelopathies, a risk stratification model should be developed in order to identify patients at higher risk. In addition to meticulous family screening, mutation carriers identified should be treated with beta-blockers even after a negative exercise test, which can change with time. Although the majority of CPVT patients are well controlled by β-blocker therapy, arrhythmic event rates on β-blocker therapy remain significant, but current data are imprecise. Thus, there is an emerging need to better clarify individuals at risk for future events. Implantation of defibrillators needs meticulous evaluation since inappropriate shocks may lead to electrical storms. Lastly, in some cases cardiac sympathetic denervation may be an alternative therapeutic option. Although sports participation is a risk taking behavior in undiagnosed and untreated CPVT, the risk may be acceptable for a well-treated and well-informed athlete following the diagnosis of CPVT.

References:
Baltogiannis GG, Lysitsas DN, di Giovanni G, et al. CPVT: Arrhythmogenesis, Therapeutic Management, and Future Perspectives. A Brief Review of the Literature. Front Cardiovasc Med. 2019;6:92. Published 2019 Jul 12. doi:10.3389/fcvm.2019.00092

Ostby SA, Bos JM, Owen HJ, Wackel PL, Cannon BC, Ackerman MJ. Competitive Sports Participation in Patients With Catecholaminergic Polymorphic Ventricular Tachycardia: A Single Center's Early Experience. JACC Clin Electrophysiol. 2016;2(3):253-262. doi:10.1016/j.jacep.2016.01.020

van der Werf C, Zwinderman AH, Wilde AA. Therapeutic approach for patients with catecholaminergic polymorphic ventricular tachycardia: state of the art and future developments [published correction appears in Europace. 2012 Dec;14(12):1810]. Europace. 2012;14(2):175-183.

Veith M, El-Battrawy I, Roterberg G, et al. Long-Term Follow-Up of Patients with Catecholaminergic Polymorphic Ventricular Arrhythmia. J Clin Med. 2020;9(4):903. Published 2020 Mar 25. doi:10.3390/jcm9040903

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