Catecholaminergic polymorphic ventricular tachycardia
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
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.
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).
ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death (DO NOT EDIT) [1]
Recommendations for Catecholaminergic Polymorphic Ventricular Tachycardia
| Class I |
| "1. Beta blockers are indicated for patients who are clinically diagnosed with CPVT on the basis of the presence of spontaneous or documented stressinduced ventricular arrhythmias. (Level of Evidence: C)" |
| "2. Implantation of an ICD with use of beta blockers is indicated for patients with CPVT who are survivors of cardiac arrest and who have reasonable expectation of survival with a good functional status for more than 1 y. (Level of Evidence: C)" |
| Class IIa |
| "1. Beta blockers can be effective in patients without clinical manifestations when the diagnosis of CPVT is established during childhood based on genetic analysis. (Level of Evidence: C)" |
| "2. Implantation of an ICD with the use of beta blockers can be effective for affected patients with CPVT with syncope and/or documented sustained VT while receiving beta blockers and who have reasonable expectation of survival with a good functional status for more than 1 y. (Level of Evidence: C)" |
| Class IIb |
| "1. Beta blockers may be considered for patients with CPVT who were genetically diagnosed in adulthood and never manifested clinical symptoms of tachyarrhythmias. (Level of Evidence: C)" |
- ↑ Zipes DP, Camm AJ, Borggrefe M, Buxton AE, Chaitman B, Fromer M; et al. (2006). "ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: a report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines (writing committee to develop Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death): developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society". Circulation. 114 (10): e385–484. doi:10.1161/CIRCULATIONAHA.106.178233. PMID 16935995.