DCM in dogs stands for Dilated Cardiomyopathy, which is a disease of the heart muscle that results in an enlarged heart. As the heart and its chambers become dilated, it becomes harder for the heart to pump, and heart valves may leak, which can lead to a buildup of fluids in the chest and abdomen (congestive heart failure) . DCM is the most common cause of heart failure in certain large breeds of dogs, such as Boxer Dogs, Doberman Pinschers, Great Danes, Irish Wolfhounds, and Saint Bernards. Occasionally, German Shepherd Dogs and some medium-sized breeds such as Cocker Spaniels, English Springer Spaniels, and Portuguese Water Dogs are also affected. Small breeds rarely develop DCM.

DCM is a serious disease that must be accurately diagnosed and aggressively treated. Unfortunately, there are no guarantees in medicine, and some dogs with DCM will never resume a normal lifestyle. The prognosis for dogs with DCM is variable depending upon breed and status at presentation. If you suspect your dog may have DCM, it is important to bring them to a veterinarian for a physical examination and diagnostic tests, which may include chest and abdominal radiographs, an echocardiogram of the heart, electrocardiogram, hormonal assays, analysis of abdominal fluid, blood work, and taurine levels.