P145 IVABRADINE IN TETRALOGY OF FALLOT AND POSTOPERATIVE JUNCTIONAL ECTOPIC TACHYCARDIA

Abstract

Abstract Introduction Ivabradine is a selective inhibitor of sodium’s If current; it acts at the level of the sinus node causing a bradycardizing effect without effect on inotropism and atrioventricular conduction. In fact, the If channel, located in pacemaker cells, is activated in hyperpolarization and allows the membrane potential to become gradually more positive until the threshold potential is reached. Previous studies have actually shown the usefulness of ivabradine not only for slowing sinus rate but also in case of atrial tachycardia and ectopic junctional tachycardia. Case report: Our patient, suffering tetralogy of Fallot, undergoes transannular patch correction surgery at the age of 6 months. During the stay in postoperative intensive care presents numerous episodes of junctional tachycardia. Therapy with amiodarone ev is undertaken, with a discrete response; on the ECG, frequent isolated and repetitive supraventricular extrasystoles (pairs and triplets) are observed. After the infusion ev is undertaken, oral therapy with amiodarone and beta–blocker is associated, but not obtaining a good rhythm control. In addition, the presence of numerous and sustained episodes of high frequency arrhythmia affects the hemodynamic parameters of the child. For the persistence of arrhythmic episodes, ivabradine therapy is undertaken at a dose of 0.05 mg/kg orally twice a day. Stable sinus rhythm is observed, so amiodarone therapy is subsequently discontinued and ivabradine therapy continued. No arrhythmias are observed either during hospitalization or in the subsequent follow–up after discharge, carried out with seriated Holter ECGs. After about 3 months, therapy is discontinued, in the absence of supraventricular and ventricular arrhythmias. Conclusions Ivabradine is a selective inhibitor of the sodium channel at the level of pacemaker cells; born as a bradycardizing drug for its action on the sinus node, its usefulness has also been demonstrated in the treatment of supraventricular arrhythmias due to enhanced automatism and atrial reentry. It is, therefore, conceivable the presence of If channels also in ectopic foci, which would allow its use as a real antiarrhythmic drug, exploiting its peculiar action not interfering with inotropism and atrium and intraventricular conduction.