Ivabradine use as an antiarrhythmic therapy in congenital junctional ectopic tachycardias

Author's Reply Thank you very much for evaluating our article entitled “Ivabradine is an effective antiarrhythmic therapy for congenital junctional ectopic tachycardia-induced cardiomyopathy during infancy: Case studies.” In this study, we presented successful management of congenital junctional ectopic tachycardia (JET)-induced cardiomyopathy by ivabradine in three cases. Since there is a limited experience on ivabradine use in congenital JET, we wish to address this issue that merits more attention.1 Ivabradine is a cardiac pacemaker cell inhibitor which is known as an If channel. If channel has a crucial physiological role in setting the heart rate and sensing its autonomic control. The antiarrhythmic effect of ivabradine is based on experimental models and limited numbers of clinical studies.2 As you mentioned, positive effect of ivabradine on ventricular arrhythmias in patientswith adrenergic discharge due to the heart failure has been shown in the literature.3 We could not make any suggestion since none of our patients had ventricular arrhythmia. The authors claimed that proposal about ivabradine use in adults to reduceheart rate in atrial fibrillation shouldbe revised.Althoughwedo not have any experience, it is suggested that ivabradine could be used for ventricular rate control in adult patientswith atrial fibrillation.4,5 In a double-blind placebo-controlled study, Wongcharoen et al.5 showed that ivabradine had significant ventricular rate reduction in adult patients with atrial fibrillations without serious side effect. Ivabradine caused prolongedAH interval and reduced ventricular rate in pigmodels with atrial fibrillation.6 As a result ivabradine might be an alternative in medical treatment of congenital JET patients. We believe that further researches are needed to unveil the effect of ivabradine and its potential as an antiarrhythmic drug.