Dilated cardiomyopathy is a serious heart disease causing the heart muscle to weaken and enlarge. It is the second most common cardiac disease in dogs and is often breed-specific.
DCM causes progressive cardiac dysfunction that affects a dog's energy, exercise tolerance, and quality of life long before overt heart failure develops. The subclinical phase is particularly concerning as dogs may be experiencing reduced cardiac output without visible symptoms, limiting their ability to exercise normally. Once congestive heart failure develops, dogs experience breathlessness, fatigue, and the distress of respiratory compromise. Ventricular arrhythmias cause episodic collapse and sudden death, which are traumatic events for both dogs and owners. Breeds known to be at high risk should receive regular cardiac screening to detect disease early and initiate medications before symptoms appear.