Accelerated Idioventricular Rhythm in Children: Adenosine Sensitivity and the Effects of Verapamil on Arrhythmias and QT Dispersion

Objectives: Accelerated Idioventricular Rhythm (AIVR) is a distinct subgroup of idiopathic ventricular tachycardia (VT) with characteristic clinical and electrophysiologic properties that have not been studied extensively in children. This study was designed to assess the efficacy of adenosine and verapamil in children with this rhythm disorder and to determine the effects of verapamil on QT dispersion in these patients. Methods: Eight patients (6 male, 2 female) with a mean age of 9.6 ± 4.8 years were enrolled in the study. QT interval analysis was performed on 12 lead surface electrocardiogram. During AIVR, intravenous adenosine was administered with increasing amount (100–300mcg/kg). If arrhythmic episode was terminated with adenosine administration, verapamil was given orally (3–10mg/kg/day) to assess its efficacy in suppression of ventricular arrhythmias and to examine its efficacy on QT dispersion. Results: Adenosine was effective in terminating arrhythmia in all patients with a mean dose of 162 ± 74 mcg/ kg. During a mean follow-up period of 17 ±8 months, verapamil was effective in suppression of arrhythmia with an average dose of 6.2 ± 2.2 mg/kg. QT dispersion decreased significantly from 81.2 ± 8.3 ms to 36.3 ± 6.0 ms (p<0.001) in patients whose arrhythmia was suppressed by verapamil therapy. Conclusion: Idiopathic VT attacks can be suppressed by intravenous adenosine administration. For a lon term therapy verapamil is a safe and highly effective drug. Moreover, verapamil decreases QT dispersion.