Canine dilated cardiomyopathy (DCM) is a progressive heart muscle disease causing cardiac enlargement, reduced pumping function, and eventually congestive heart failure — affecting certain large breeds disproportionately and requiring careful management to extend quality life.
DCM causes suffering across a spectrum — from the chronic fatigue and exercise intolerance of moderate disease, to the acute distress of pulmonary edema (fluid in the lungs) in decompensated heart failure, to the sudden cardiac death that claims some dogs without warning. The welfare challenge is that the disease is often silent until late stage, meaning dogs may be suffering from reduced cardiac output — weakness, fatigue, difficulty breathing with exertion — long before owners recognize the problem. Breed-appropriate screening programs that use echocardiography in at-risk breeds before clinical signs appear allow treatment to begin early, extending the period of comfortable, good-quality life. Sudden cardiac death, while itself not suffering for the dog, is enormously traumatic for owners who had no indication their dog was ill.