Clinical and genetic profile of catecholaminergic polymorphic ventricular tachycardia in Hong Kong Chinese children

Objective To report our experience in the management of catecholaminergic polymorphic ventricular tachycardia in Hong Kong Chinese children. Methods This case series study was conducted in a tertiary paediatric cardiology centre in Hong Kong. All paediatric patients diagnosed at our centre with catecholaminergic polymorphic ventricular tachycardia from January 2008 to October 2014 were included. Results Ten patients (five females and five males) were identified. The mean age at presentation and at diagnosis were 11.0 (standard deviation, 2.9) years and 12.5 (2.8) years, respectively. The mean delay time from first presentation to diagnosis was 1.5 (standard deviation, 1.3) years. They presented with recurrent syncope and six patients had a history of aborted cardiac arrest. Four patients were initially misdiagnosed to have epilepsy. Catecholaminergic polymorphic ventricular tachycardia was diagnosed by electrocardiogram at cardiac arrest (n=2), or provocation test, either by catecholamine infusion test (n=6) or exercise test (n=2). Mutations of the RyR2 gene were confirmed in six patients. Nine patients were commenced on beta-blockers after diagnosis. Despite medications, three patients developed aborted or resuscitated cardiac arrest (n=2) and syncope (n=1). Left cardiac sympathetic denervation was performed in five patients and an implantable cardioverter defibrillator was implanted in another. There was no mortality during follow-up. Conclusions Catecholaminergic polymorphic ventricular tachycardia should be considered in children who present with recurrent syncope during exercise or emotional stress. Despite beta-blocker treatment, recurrent ventricular arrhythmias occur and may result in cardiac arrest.