Cardiomyopathy or Ventricular Arrhythmia is specific to the boxer and sometimes seen in English bulldogs. It is characterized by an irregular heartbeat. Fainting, sudden heart failure or congestive heart failure can happen. Typically it is seen in dogs that are two years old, although symptoms have been seen to occur in dogs from six months to ten year olds.
Symptoms may include an irregular heartbeat, fainting, coughing, rapid breathing, accumulation of fluid in the abdomen or even sudden death.