Using an experimental induced mitral valve regurgitation dog model, the administration of ACE inhibitors failed to improve left ventricular remodeling and function; whereas, the most recent retrospective study demonstrated that ACE inhibitors have some beneficial effects including a decreased risk of death and a prolonged asymptomatic period in asymptomatic dogs other than CKCS and King Charles spaniels affected by MVD with moderate to severe mitral valve regurgitation. Because of the conflict among studies and insufficient supporting data, the effect of ACE inhibitors upon the onset of heart failure and cardiac remodeling is still uncertain.