A Rare Case of RYR2 Mutation Causing Sudden Cardiac Arrest Due to Catecholaminergic Polymorphic Ventricular Tachycardia

Abstract

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a complex disorder that can induce lethal ventricular arrhythmias, secondary to activation of the sympathetic nervous system. This disease is often diagnosed in childhood but can also manifest in adulthood (the early 40s). Gene mutations such as CALM1, RYR2 (ryanodine receptor-2), CASQ2, and TRDN have been identified as common causes of CPVT. Those affected can present with episodes of syncope, sudden cardiac arrest, or sudden cardiac death due to either fast polymorphic ventricular tachycardia (VT) or bidirectional VT. Diagnosing and managing CPVT can often be challenging as patients are often asymptomatic and may present after a sudden cardiac arrest. Exercise stress testing and genetic testing play a pivotal role in the workup of CPVT. Avoidance of strenuous activities and pharmacological therapy with beta-blockers are the mainstays of treatment. Here, we report a case of CPVT in a patient with RYR2 gene mutation, causing sudden cardiac arrest.

Keywords: catecholaminergic polymorphic ventricular tachycardia; ryr-2 gene mutation.

Figure 1. Initial EKG post-ROSC showing sinus bradycardia with a measured QTc of 609 msec

EKG - electrocardiogram; ROSC - return of spontaneous circulation

Figure 2. Rhythm shown is polymorphic ventricular tachycardia (PMVT) reproduced during the electrophysiological study