Catecholaminergic Polymorphic Ventricular Tachycardia

Abstract

Catecholaminergic polymorphic ventricular tachycardia Prof. Antoine Leenhardt Lariboisiere University Hospital, Paris, France Catecholaminergic polymorphic ventricular tachycardias (CPVT) represent a clearly defined but still insufficiently recognized entity. They have a poor spontaneous outcome. The consequence of misdiagnosis is sudden death in children with an otherwise normal heart. They are responsible for syncope and include the risk of sudden death in young patients with no structural heart disease and a normal QT. Ventricular tachyarrhythmias are reproducibly induced by any form of sympathetic stimulation. It is crucial to make the parents and the child aware of the necessity of faultless compliance to beta-blockers. The prevalence of CPVT in the general population has been estimated 1 in 10000. CPVT is mostly the result of mutations in genes encoding the cardiac ryanodine receptor Ca²⁺ release channel (RyR2) or cardiac calsequestrin (CASQ2), which cause spontaneous RyR2 channel openings and trigger delayed afterdepolarizations. Cardiac events are not rare in both probands and affected family members, even while taking beta-blockers, which are associated with a lower event rate. Implantation of an ICD is recommended as primary prevention when syncope or sustained VT persist despite maximal tolerable dose of beta-blockers. Nevertheless, an ICD is not fully protective, and can even be proarrhythmic. Shocks may trigger catecholamine release, subsequently resulting in arrhythmic storms, multiple shocks, and death. There is a need for further therapies that should improve the outcome of these patients.