Clinical Characteristics and Outcomes of Catecholaminergic Polymorphic Ventricular Tachycardia in Children

  • Bo Sang Kwon, Korea
  • Gi Beom Kim, Department of Pediatrics, College of Medicine, Seoul National University, Seoul, Korea
  • Eun Jung Bae, Department of Pediatrics, College of Medicine, Seoul National University, Seoul, Korea
  • Chung Il Noh, Department of Pediatrics, College of Medicine, Seoul National University, Seoul, Korea
  • Jung Yun Choi, Department of Pediatrics, College of Medicine, Seoul National University, Seoul, Korea
  • Yong Soo Yun, Department of Pediatrics, College of Medicine, Seoul National University, Seoul, Korea

    • Introduction: Catecholaminergic polymorphic ventricular tachycardia(CPVT) is a highly malignant and unclear arrhythmia. The objectives were to characterize the clinical and electrocardiograhpic features of CPVT.
    Methods: We studied retrospective analysis of 11 patients(M:F=9:2) diagnosed as CPVT from 1984 to 2008 in a tertiary center.
    Results: The ages at the first event and at diagnosis were 6.8±2.8(1.3-10.0)years and 9.5±2.2(6.8-12.0)years. The interval of diagnostic delay was 2.0±1.6(0-5)years. The most common misleading diagnosis was epilepsy. Initial presentation of all was syncope related to exercise or emotional stress. All 5 early onset patients (less than 7 years of age) showed accompanying learning disability and developmental delay. Resting ECG showed sinus bradycardia, 55±7(48-76)bpm, and QTc was 0.42±0.03(0.40-0.49)sec. There were U wave in 9 patients, J wave in 5, sinus pause in 2, and wandering pacemaker in 2. On ECG during CPVT, mean heart rate, QRS duration, coupling interval, QT and QTc immediately before CPVT, and VT index were 184±21(169-240)bpm, 0.12±0.03(0.08-0.18)sec, 0.33±0.04(0.26-0.40)sec, 0.31±0.06(0.22-0.44)sec, 0.45±0.07(0.37-0.59)sec, and 1.11±0.17(0.78-1.29), respectively. Sinus rate before the onset of CPVT was 131±24(95-160)bpm. Polymorphic and bidirectional VT was documented in all patients. Five patients also had atrial tachycardia. All patients took beta-blocker. The Six out of 11 patients died suddenly(4/6) or had rescued cardiac arrest(2/6) during 7.1±4.2(0.6-14.3)years of follow-up. Aborted cardiac arrest was a risk factor of sudden death. Although 1 patient underwent ICD implantation, he suffered from several episodes of electrical storm. RyR2 mutation was documented in 1/5 patients.
    Conclusion: CPVT patients have still had unsatisfactory and limited prognoses despite medical therapy.