Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a severe genetic arrhythmogenic disorder characterized by adrenergically induced ventricular tachycardia (VT) manifesting as syncope and sudden death.
The prevalence of CPVT in Europe is 1/10,000.
Typical age of onset of CPVT is between 7 and 9 years of age with no sex difference. Syncopal spells, brought on by exercise or acute emotion, are frequently the first symptom observed. Sudden death can be the first manifestation of the disease in a subset of patients (10-20%). The typical arrhythmias of CPVT are bidirectional ventricular tachycardia and, less frequently, supraventricular tachycardia and atrial fibrillation.
The two genes responsible for CPVT that have been discovered to date, are the cardiac ryanodine receptor (RyR2) gene, which is the cause of CPVT in approximately 55% to 65% of cases, and the cardiac calsequestrin gene (CASQ2), seen much less frequently in approximately 2% of CPVT cases. Mutations on the KCNJ2 gene, which in the majority of cases is linked with Andersen syndrome (see this term), can produce adrenergic-dependent bidirectional tachycardia in the absence (or very mild presence) of other signs of the disease, thus producing a CPVT phenocopy.
Subjects with a family history of CPVT or sudden death during stress or syncope induced by exercise/emotion should undergo exercise stress test and Holter monitoring. Usually the arrhythmias are reproducible, thus graded exercise is of utmost diagnostic relevance. Holter monitoring is also indicated for the rarer cases where acute emotion represents a more powerful trigger. Resting ECG is usually unremarkable. Cardiac imaging (echocardiogram and MRI) is normal in typical CPVT.
The principal differential diagnoses are the long QT syndrome (LQTS), arrhythmogenic right ventricular cardiomyopathy (ARVC), and Andersen-Tawil syndrome (see these terms).
Antenatal diagnosis can be performed in families with high penetrance and high lethality mutation.
When there is a family history of CPVT, genetic testing of family members is recommended. Screening for the RyR2 mutation (which follows an autosomal dominant pattern of inheritance) is indicated in all CPVT patients. Screening of CASQ2 is indicated with evidence of recessive inheritance, in case of parental consanguinity and in case of negative RyR2 screening.
Beta blockers (nadolol and propranolol) are the first treatment option for patients with CPVT and the maximum tolerated dose should be administered to control arrhythmias. Recently flecainide (a sodium channel blocker), has shown good results in suppressing arrhythmias in CPVT patients. Implantable cardioverter defibrillators (ICDs) are recommended in CPVT patients with recurrent syncope (despite full dosage beta blockers and flecainide therapy) to prevent cardiac arrest and sudden death. Left cardiac sympathetic denervation was successful in eliminating arrhythmias in a few cases, but its efficacy is still to be confirmed. Physical activity is to be strongly limited in CPVT patients.
Although CPVT is a severe and often deadly disease, early diagnosis and proper treatment can greatly increase life expectancy. Exercise restriction along with beta-blocker therapy and ICD implants in patients with recurrent symptoms has resulted in a favorable prognosis.
Last update: July 2011
- Dr Raffaella BLOISE
- Dr Carlo NAPOLITANO
- Pr Silvia G. PRIORI