['Ivabradine is a heart rate (HR)-lowering agent acting by inhibiting the If-channel. Dobutamine does increase the HR and has some deleterious effects on myocardium. So, we aimed to evaluate whether ivabradine treatment blunts a dobutamine-induced increase in HR.', 'The main study population consisted of 58 acute decompensated heart failure patients requiring inotropic support with left-ventricular ejection fraction below 35%, who were randomized to ivabradine (n\u200a=\u200a29) or control (n\u200a=\u200a29). All patients underwent Holter recording for 6\u200ah and then dobutamine was administered at incremental doses of 5, 10 and 15\u200aμg/kg/min, with 6-h steps. Holter recording was continued during dobutamine infusion. Ivabradine 7.5\u200amg was given at the initiation of dobutamine and readministered at 12\u200ah of infusion. Also, a nonrandomized beta-blocker group with 15 patients receiving beta-blocker was included in the analysis. Control and beta-blocker groups did not receive ivabradine.', 'In the control group, mean HR gradually and significantly increased at each step of dobutamine infusion (81\u200a±\u200a11, 90\u200a±\u200a16, 97\u200a±\u200a14 and 101\u200a±\u200a16\u200ab.p.m., respectively; P\u200a=\u200a0.001), whereas no significant increase in HR was observed in the ivabradine group (82\u200a±\u200a17, 82\u200a±\u200a15, 85\u200a±\u200a14 and 83\u200a±\u200a12\u200ab.p.m., respectively; P\u200a=\u200a0.439). Mean HR was also found to significantly increase during dobutamine infusion in the beta-blocker group (75\u200a±\u200a13, 82\u200a±\u200a13, 86\u200a±\u200a14 and 88\u200a±\u200a13\u200ab.p.m., respectively; P\u200a=\u200a0.001). The median increase in HR from baseline was significantly higher in the control group compared to those in the ivabradine group (5 vs. 2\u200ab.p.m.; P\u200a=\u200a0.007 at first step, 13 vs. 5\u200ab.p.m.; P\u200a=\u200a0.001 at second step and 18 vs. 6\u200ab.p.m.; P\u200a=\u200a0.0001 at third step of dobutamine, respectively).'] Does ivabradine treatment prevent dobutamine-induced increase in heart rate in patients with acute decompensated heart failure?