Clinical and Electrophysiological Correlates of Incessant Ivabradine-Sensitive Atrial Tachycardia

Abstract

Background: Incessant focal atrial tachycardia (FAT), if untreated, can lead to ventricular dysfunction and heart failure (tachycardia-induced cardiomyopathy). Drug therapy of FAT is often difficult and ineffective. The efficacy of ivabradine has not been systematically evaluated in the treatment of FAT. Methods: The study group consisted of patients with incessant FAT (lasting >24 hours) and structurally normal hearts. Patients with ventricular dysfunction as a consequence of FAT were not excluded. All antiarrhythmic drugs were discontinued at least 5 half-lives before the initiation of ivabradine. Oral ivabradine (adults, 10 mg twice 12 hours apart; pediatric patients: 0.28 mg/kg in 2 divided doses) was initiated in the intensive care unit under continuous electrocardiographic monitoring. A positive response was defined as the termination of tachycardia with the restoration of sinus rhythm or suppression of the tachycardia to <100 beats per minute without termination within 12 hours of initiating ivabradine. Results: Twenty-eight patients (mean age, 34.6±21.5 years; women, 60.7%) were included in the study. The most common symptom was palpitation (85.7%) followed by shortness of breath (25%). The mean atrial rate during tachycardia was 170±21 beats per minute, and the mean left ventricular ejection fraction was 54.7±14.3%. Overall, 18 (64.3%) patients responded within 6 hours of the first dose of ivabradine. Thirteen of 18 ivabradine responders subsequently underwent successful catheter ablation. FAT originating in the atrial appendages was a predictor of ivabradine response compared with those arising from other atrial sites ( P =0.046). Conclusions: Ivabradine-sensitive atrial tachycardia constitutes 64% of incessant FAT in patients without structural heart disease. Incessant FAT originating in the atrial appendages is more likely to respond to ivabradine than that arising from other atrial sites. Our findings implicate the funny current in the pathogenesis of FAT.

Ectopic Atrial Tachycardia in a 12-Month-Old Girl Treated With Ivabradine and Beta-Blocker, a Case Report

“…It seems likely that ivabradine could therefore be useful in patients with EAT too. There are first reports on the efficacy of Ivabradine to control EAT in adult patients as well as in older children and adolescents (6)(7)(8)(9). On this basis we started oral Ivabradine in our young patient and restored sinus rhythm within 2 days by a combination therapy with metoprolol.…”

“…In the pediatric age group there are currently only case reports and a few small case series published. While two case series demonstrated a promising effect with congenital junctional ectopic tachycardia (JET) in infants (4,5), reports on its application in EAT are limited to older children and adults (6)(7)(8)(9). Reports on the use of Ivabradine in infants or/and young children with EAT are scarce (9).…”

Beyond Heart Failure and Ischemic Heart Disease: A Scoping Review of Novel Uses of Ivabradine in Adults

“…Our search identified six additional studies evaluating the use of ivabradine to treat other tachyarrhythmias. Two observational cohorts investigated the use of ivabradine to treat incessant atrial tachycardia in children and adults 46,47 . Termination of atrial tachycardia or HR reduction (“positive response”) was observed in 25–64% of 56 patients treated with ivabradine across both studies.…”

Incessant Focal Atrial Tachycardia Leading to Tachycardiomyopathy

“…Drug therapy with amiodarone has moderate efficacy but significant long-term side effects. Therapy with ivabradine has shown benefit in ATs arising from atrial appendages and can be used while awaiting ablation [8].…”