Pimobendan is a calcium sensitizer with positive inotropic and vasodilator effects. It is also a selective inhibitor of phosphodiesterase III (PDE3). Pimobendan is used in the management of heart failure in dogs, most commonly caused by myxomatous mitral valve disease (also known as endocardiosis), or dilated cardiomyopathy. Research has shown that pimobendan increases survival time and improves quality of life in patients with congestive heart failure secondary to mitral valve disease when compared with benazepril, an angiotensin-converting-enzyme (ACE) inhibitor. Pimobendan is a positive inotrope. It sensitizes and increases the binding efficiency of cardiac myofibril to the calcium ions that are already present without increasing the consumption of oxygen and energy. Pimobendan also causes peripheral vasodilation by inhibiting the function of phosphodiesterase III.