Catecholaminergic polymorphic ventricular tachycardia

Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is an inherited heart rhythm disorder caused by a mutation in voltage gated ion channels and resulting in arrhythmias. CPVT may cause exercise-induced ventricular arrhythmias and/or syncope occurring during physical activity or acute emotion, but demonstrates no structural problems of the heart. Ventricular tachycardia may self-terminate or degenerate into ventricular fibrillation, causing sudden death without immediate cardiopulmonary resuscitation. The majority of events occur during childhood and more than 60% of affected individuals will have a first episode of syncope or cardiac arrest by age 20.

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Inheritance: CPVT has an autosomal dominant inheritance pattern. There are two genes currently associated with CPVT: RYR2 (majority) and CASQ2 (1-2%). The Ryanodine receptor (RYR2) is involved in intracardiac Ca2+ handling; Ca2+ overload triggers abnormal cardiac activity. Calsequestrin (CASQ2) is a calcium buffering protein of the sarcoplasmic reticulum.

Diagnosis: CPVT is diagnosis based on reproducing ventricular arrhythmias during exercise stress testing, syncope occurring during physical activity and acute emotion, and a history of exercise or emotion-related palpitations and dizziness with an absence of structural cardiac abnormalities. The resting electrocardiogram is usually unremarkable but can show sinus bradycardia and a prominent "U". Genetic testing is sometimes available and is particularly useful for presymptomatic diagnosis of related individuals.

Treatment: CPVT is treated with beta blockers, verapamil or an ICD (implantable cardiac defibrillator).