What is the mechanism of action of pimobendan?

Pimobendan is classified as an inodilator, meaning it has both inotropic (affecting the force of heart contraction) and vasodilatory (affecting blood vessel dilation) effects. Its primary mechanism of action involves increasing the sensitivity of cardiac myofilaments to calcium. By enhancing calcium sensitization of troponin, pimobendan increases myocardial contractility without a corresponding increase in intracellular calcium levels. This is particularly beneficial in conditions such as congestive heart failure, where increased contractility can help improve cardiac output and alleviate symptoms.

This mechanism is advantageous because it can lead to improved cardiac function with fewer side effects related to calcium overload, which can happen with traditional positive inotropic agents. By focusing on enhancing the heart's responsiveness to calcium, pimobendan helps optimize cardiac performance while minimally impacting other physiological processes, such as heart rate or systemic vascular resistance.

While other options relate to aspects of cardiovascular function, they do not accurately describe the primary action of pimobendan. For instance, while it may have some effect on blood flow and pressure, those are secondary results of its primary mechanism of improving calcium sensitivity.