OBJECTIVES: To assess the safety, tolerability and efficacy of ivabradine administered to patients experiencing decompensated heart failure who were undergoing inotropic therapy and developed undesirable sinus tachycardia.
METHODS: The present study prospectively included consecutive patients with ischemic-necrotic cardiomyopathy and an ejection fraction <35% who were admitted for decompensated heart failure while undergoing inotropic therapy and developed undesirable sinus tachycardia. Patients experiencing shock, or requiring respiratory or circulatory mechanical support, or those presenting with a heart rhythm other than sinus were excluded. Hemodynamic measurements using a pulmonary artery catheter were performed before and 3 h after an oral dose of 15 mg of ivabradine. Adverse side effects and tolerance were evaluated.
RESULTS: The present study included 52 patients (32 men, 20 women) with a mean age of 65.6 years and a mean ejection fraction of 31.5%, who were undergoing inotropic treatment (15 μg/kg). Three hours after ivabradine administration, a reduction in mean (± SD) heart rate from 121±6 beats/min to 98±7 beats/min (P=0.00002) was observed, with an incremental increase in systolic volume from 37.9±5 mL to 47.3±8 mL (P=0.00002) and an increase in cardiac output from 4597±550 mL/min to 4825±535 mL/min (P=0.041). No differences were observed in filling pressures, or systemic or pulmonary resistances. There was good clinical tolerance without hypotension, bradycardia or episodes of atrioventricular block.
CONCLUSIONS: Ivabradine proved to be useful and safe for controlling undesirable sinus tachycardia in patients undergoing inotropic treatment.
