Lasting reduction of heart transplant tachycardia with ivabradine is effective and well tolerated: results of 48-month study

Abstract

The safety and efficacy of ivabradine applied in heart transplant (HTx) recipients with permanent sinus tachycardia (PST) has been depicted in previous short-term follow-up studies. We sought to investigate the long-term impact of ivabradine in this patient population. From May to November 2006, 29 HTx recipients with PST, who exhibited either contraindications or intolerance of beta-blocker medication or insufficient heart rate (HR) reduction on beta-blocker treatment, first received oral ivabradine treatment (5 mg bid). Ivabradine treatment was discontinued in three patients due to adverse events within the first week. In the remaining 26 patients, resting HR was significantly lowered from 106.8 ± 9.2 at baseline to 83.2 ± 5.1 bpm after 3 months (p < 0.001). This effect remained stable in the long-term follow-up (82.1 ± 11.8 bpm after 4 years), whilst blood pressure was not affected. Apart from the corrected QT interval (QTc), there were no significant changes in ECG. The elongated QTc at baseline (469.4 ± 29.5 ms) decreased to 444.3 ± 33.1 ms after 3 months ivabradine treatment (p < 0.001). A decrease in QTc until month 9 was observed, followed by a partial increase to the upper limit of the normal value. Neither allograft rejection nor changes in left ventricular ejection fraction were observed over the follow-up period. In conclusion, ivabradine appears to be a safe and feasible long-term therapeutic option for HTx recipients with PST. It reduced the resting HR without impairment of blood pressure, myocardial contractility and cardiac conduction. The prognostic value of normalised QTc following ivabradine administration requires further observation.