Letter to the EditorPolymorphic ventricular tachycardia after use of intravenous amiodarone for postoperative junctional ectopic tachycardia
Introduction
Junctional ectopic tachycardia (JET) occurs rarely as a congenital arrhythmia and is encountered more frequently after repair of congenital heart defects [1]. The ECG is characterised by atrioventricular dissociation with a ventricular rate higher than the atrial rate (Fig. 1). Rapid junctional rates may lead to significant haemodynamic impairment [2]. The majority of antiarrhythmic drugs have little effect on this arrhythmia. Previous reports in small numbers of patients have shown that intravenous amiodarone may reduce the ventricular rate, with consequent haemodynamic improvement [3], [4]. This report presents three boys with congenital cardiac defects who developed polymorphic ventricular tachycardia after intravenous amiodarone given for postoperative JET.
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Case report
Patient 1 with total anomalous pulmonary venous return to the coronary sinus and coarctation of the aorta was operated at 8 days of age. Six hours later he developed JET with a ventricular rate of 230 beats per minute. He was given intravenous amiodarone according to a previously published protocol [4]. First a bolus dose of 5 mg/kg body weight was given over 60 min. Thereafter a continuous infusion of amiodarone (total daily dose 10 mg/kg/day) was started. Ventricular fibrillation resulted 12
Discussion
Amiodarone is a class 3 antiarrhythmic agent. Its mechanism of action in JET may relate to its inhibition of abnormal automaticity. All three patients in whom amiodarone was used developed ventricular tachycardia, and a causal effect of amiodarone may be assumed. Two of the three patients did not survive. Serum levels of amiodarone were in the recommended therapeutic range in two of the three patients, and were subtherapeutic in patient 2. Other methods of controlling ventricular rate, such as
References (5)
- et al.
Junctional tachycardia in infants and children after open heart surgery for congenital heart disease
Am J Cardiol
(1987) - et al.
Clinical efficacy and safety of intravenous amiodarone in infants and children
Am J Cardiol
(1994)