Catecholaminergic polymorphic ventricular tachycardia: Electrocardiographic characteristics and optimal therapeutic strategies to prevent sudden death

Abstract

Objective: To investigate the clinical outcome, ECG characteristics, and optimal treatment of catecholaminergic polymorphic ventricular tachycardia (CPVT), a malignant and rare ventricular tachycardia. Patients and methods: Questionnaire responses and ECGs of 29 patients with CPVT were evaluated. Mean (SD) age of onset was 10.3 (6.1) years. Results: The initial CPVT manifestations were syncope (79%), cardiac arrest (7%), and a family history (14%). ECGs showed sinus bradycardia and a normal QTc. Mean heart rate during CPVT was 192 (30) beats/min. Most cases were non-sustained (72%), but 21% were sustained and 7% were associated with ventricular fibrillation. The morphology of CPVT was polymorphic (62%), polymorphic and bidirectional (21%), bidirectional (10%), or polymorphic with ventricular fibrillation (7%). There was 100% inducement of CPVT by exercise, 75% by catecholamine infusion, and none by programmed stimulation. No late potential was recorded. Onset was in the right ventricular outflow tract in more than half the cases. During a follow up of 6.8 (4.9) years, sudden death occurred in 24% of the patients, 7% of whom had anoxic brain damage. Autosomal dominant inheritance was seen in 8% of the patients' families. β Blockers completely controlled CPVT in only 31% of cases. Calcium antagonists partially suppressed CPVT in autosomal dominant cases. Conclusions: CPVT may arise in certain distinct areas but the prognosis is poor. The onset of CPVT may be an indication for an implanted cardioverter-defibrillator.