Catecholaminergic Polymorphic Ventricular Tachycardia in Children

ABSTRACT

PURPOSE: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is the disease entity of adrenergic dependent, potentially lethal tachyarrhythmia in a child with no structural heart disease, which manifest itself as a syncope or sudden death. The objective of this study is to present our experiences on this important, although rare, disease. METHODS: Retrospective analysis of 5 patients with episodes of syncope related to exercise, who were referred to our hospital from January 1985 to December 1998. RESULTS: All patients were male and the mean age at the time of the first syncopal episode was 5.1+/-3.2 years (range 1.3 to 10 years). There were no structural cardiac abnormalities in clinical and laboratory evaluations. In all, polymorphic ventricular tachycardia showing the characteristic pattern of CPVT in which, as the heart became stimulated adrenergically, isolated ventricular premature beats appeared, increased with rate, became polymorphic, finally formed burst with bidirectional salvoes and disappeared in resting state was induced during exercise test and/or isoproterenol infusion test. During the mean follow up period of 3.75+/-3.1 years (range 1 month to 7.3 years), one died suddenly. In this case, low dose of beta-blocker was administered because of associated sinus bradycardia resulting in incomplete control of the syncopal episodes. The other 4 cases were alive and asymptomatic by means of adequate modification of beta-blocker dosage and method of administration. CONCLUSIONS: This study emphasizes that CPVT is an important, although rare, cause of exercise related syncope in children and can be diagnosed by means of exercise test and/or isoproterenol infusion. beta-blockers were very effective in all cases, even though increasing amount of beta-blocker was frequently necessary to control ventricular arrhythmia in some cases.