This supplementary information is presented as submitted by the corresponding author. It has not been copy-edited by NTvG.
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare inherited cardiac arrhythmia syndrome. CPVT is characterized by emotion- and exercise-induced polymorphic ventricular arrhythmias that may lead to sudden cardiac death. Here we describe two cases that illustrate that CPVT is under-recognized in clinical practice.
The first patient, a 38-year-old asymptomatic male, was evaluated at a cardiology outpatient clinic because of a family history of multiple cases of sudden death in young relatives during exercise or emotions. Comprehensive cardiologic evaluation revealed polymorphic ventricular arrhythmias during exercise testing as the only abnormality, but this was not recognized as CPVT and the patient was reassured. Later, the patient presented to us for a second opinion. We diagnosed the patient with CPVT, started him on a beta-blocker, and identified the disease-causing mutation in the RYR2 gene. The second patient, a 28-year-old female was diagnosed with CPVT after suffering an aborted cardiac arrest. She had been evaluated by several specialists in the past because of several emotion- and exercise-induced syncopal episodes from the age of ten. Her family history was unremarkable. Even though exercise testing and Holter showed ventricular arrhythmias typical for CPVT, she was not treated or followed-up. After the cardiac arrest a beta-blocker was started, an implantable cardioverter-defibrillator was implanted, and a mutation in the RYR2 gene was identified.
The two cases show the different faces of catecholaminergic polymorphic ventricular tachycardia. The first patient was asymptomatic, but had a family history suggestive of CPVT. The second patient had typical symptoms of CPVT. Because of its low prevalence (estimated at 1 in 10.000) many adult- and pediatric cardiologists are not familiar with CPVT. The cases include several important clues that may point to CPVT. Syncopal episodes are prevalent in young individuals. However, when these episodes are exercise-induced or in a patient with a family history of sudden death, cardiologic evaluation is recommended. Exercise-induced ventricular arrhythmias can also be caused by coronary artery disease (CAD), cardiomyopathies, mitral valve prolapse or the congenital long-QT syndrome. Contrary to these conditions, the resting ECG and echocardiogram are normal in patients with CPVT. In patients over the age of 40, CAD should be excluded before diagnosing a patient with CPVT. In individuals presenting because of a family history of sudden death in the young, inherited arrhythmia syndromes, inherited cardiomyopathies and premature atherosclerosis need to be considered. The initial evaluation of these individuals usually includes resting ECG, exercise testing, Holter monitoring, echocardiography and blood cholesterol testing. Details on the circumstances of the familial sudden death cases is critical and may, in case of exercise or emotions as triggering factors, point to CPVT.