Heart Disease: Cardiac disease is very common in dogs and cats. The most common symptom in dogs during the early stages is a heart murmur, but may also include be a change in the heart rhythm. Other common symptoms are a poor tolerance to exercise, coughing, wheezing, or fainting. Cats will usually show fewer symptoms, but may exhibit open-mouth breathing, breathing difficulty, or a hacking sound that is often thought to be hairballs at first. Any sign of heart disease should be investigated early as many options are available to treat heart disease. Diagnosis is by x-ray, EKG, and echocardiography. The DVM Hospital group cardiologist performs about eight echocardiograms a week to evaluate heart murmurs, arrhythmias, and ongoing cardiac patients. Treatment, when indicated, may include oral medications, a special diet, or even a pacemaker. Many cases do not require actual treatment in the early stages, but only a periodic monitoring of the condition and many patients will live a full healthy life without medication ever being required.