Other symptoms include coughing, difficulty breathing and exercise intolerance. Respiratory signs and vomiting are the most common reported signs. The traditional methods used to diagnose heartworm infection in dogs are not accurate for the diagnosis in cats. Part of this stems from the small number of heartworms that most cats carry compared to dogs. Since even one worm can be lethal, tests that are able to accurately detect early infections or small worm burdens are crucial in the diagnosis of the heartworm infection and disease.
Chest radiographs can be useful if the cat is symptomatic.
Echocardiography is also useful but requires good equipment and a skilled operator. Even then, the worms may be located further out in the pulmonary artery and not be seen by echocardiography. Until a perfect test for feline heartworms is developed, the diagnosis of heartworm infection or disease will rely upon putting together the pieces of the heartworm puzzle until the picture is clear. If you live in an area that is considered endemic for heartworms then your cat is at risk for getting heartworms, if your veterinarian recommends that your dog be tested then heartworms are probably a problem in your area. Heartworm infection is endemic in Florida.