Pharmacodynamics of single-dose omecamtiv mecarbil administered intravenously in clinically healthy cats.

Background: Omecamtiv mecarbil (OM), a selective cardiac myosin activator, is gaining attention as a potential heart failure (HF) treatment because it can enhance cardiac contractility without adverse effects. Concerns were raised about arrhythmias with conventional HF treatments in cats. Despite OM's promise in veterinary medicine, no studies have confirmed its efficacy in cats. Aim: This study aimed to investigate the pharmacodynamics of OM in cats. Methods: Five clinically healthy cats were used. OM's efficacy was examined in three doses: 0.1, 0.25, and 1.0 mg/kg. To minimize the effect on heart rates, the cats were under general anesthesia, and baseline measurements were taken after the heart rate and blood pressure had stabilized. OM was administered as a single intravenous injection. Echocardiography was performed 15, 30, 60, 90, and 120 minutes after administration. Heart rate and blood pressure were measured before each echocardiographic examination. Results: The heart rates decreased at all doses; significant reductions were seen at 0.25 and 1.0 mg/kg. All doses enhanced cardiac contractility, showing a dose-dependent effect. Blood pressure remained unchanged. Conclusion: OM enhances cardiac contractility in cats, with 0.25 mg/kg being the optimal dose.