Aim of this retrospective analysis was to evaluate the effects of ivabradine given primarily as a heart rate-lowering agent on allograft function and cardiopulmonary performance in heart transplant recipients with permanent sinus tachycardia. Starting May 2006, 26 heart transplant recipients with permanent sinus tachycardia received ivabradine (5 mg bid). It was discontinued early in 3 patients (11.5%) due to adverse events. In the remaining 23 patients, resting heart rate (HR) was significantly lowered from 106.3 +/- 9.1 to 82.2 +/- 6.3 bpm after 3 weeks of treatment. The effect remained constant during the remaining treatment period, whereas resting blood pressure was not affected. After 12 weeks of ivabradine treatment, the corrected QT interval was significantly reduced into the range seen in normal individuals. Left ventricular (LV) end-diastolic posterior wall thickness, LV mass and LV mass index were also found to have decreased significantly. There was a trend to improvement of cardiopulmonary performance and LV ejection fraction, both of which did not reach statistical significance, however. It may be concluded that ivabradine successfully reduced the resting HR of heart transplant recipients with sinus tachycardia without negatively influencing the blood pressure. The definitive impact of ivabradine on LV mass regression and cardiopulmonary performance require further prospective, randomized and controlled trials.