Check limping cat for heart disease

You wouldn't normally associate limping with heart disease. When my friend Jim's cat began limping, he thought she had pulled a muscle. A visit to the vet revealed a much more serious problem; Babette was suffering from "aortic saddle thrombosis." A blood clot was cutting off circulation to her hind quarters, and in spite of all their efforts, Babette did not survive. Jim wants to alert cat owners to recognize the symptoms of heart disease.

Cardiomyopathy is the term applied to abnormalities of heart muscle function. It describes a diminished pumping ability that results in fatigue, fluid collection in the lungs, abdomen and limbs, or clots that can travel through the body. It is a sneaky disease, often going undiscovered until a crisis occurs.

There are three forms of cardiomyopathy that affect both dogs and cats. With dilated cardiomyopathy the heart muscle is weak and floppy. There is a reduction in heart muscle function during contraction and blood flow is decreased. This causes a backup of blood and enlargement of the upper heart chamber, and fluid in the lungs.

Hypertrophic cardiomyopathy (HCM) is a thickening of the lower heart muscle chambers, and is the most common heart disease in cats. This leads to inappropriate heart function, obstructed blood flow of the heart and enlargement of the heart. Cats will often develop a heart murmur along with HCM. The heart fails to relax fully, fill and then empty, a diastolic dysfunction resulting in pressure into the lungs and clinical signs of coughing and respiratory distress.

Finally, restrictive (or unclassified) cardiomyopathies are unidentified conditions in which heart problems are associated with severely enlarged upper chambers and diminished pumping ability.

This can clinically mimic HCM, but the ventricular muscle is not thickened, just dysfunctional. The heart cannot fill and then pump blood adequately.

Saddle Thrombus (or aortic saddle thrombosis) is a complex and life-threatening condition that occurs without warning. It can occur in any of the forms of heart disease but is most often seen as part of HCM. Symptoms include weakness or lameness in the rear legs, extreme pain, hyperventilation and vocalization. You can check for blood circulation by looking at the pink toenails -- they will appear bluish from lack of oxygen if there is a clot. Even with quick medical treatment, prognosis is not good. Your veterinarian may decide that emergency surgery to remove the clot is the best course of action, or if surgery is not an option for other medical reasons the animal may be given drugs to break up the clot. If your pet survives this episode, it may need long-term anticoagulation therapy.

Both dogs and cats develop heart disease. Dogs most often develop the dilated form of cardiomyopathy, while cats are prone to HCM or restrictive forms. Since clinical signs usually develop rapidly and without warning, it is very important that pet owners be aware of the dangers of heart disease. Your veterinarian will need a thorough history on your pet that includes any coughing, panting, fainting, limb weakness or fluid collection around the lungs and abdominal cavity if heart disease is suspected. Radiographs (x-rays) may show enlargement of the heart, and an electrocardiogram can diagnose any irregular heart rhythms. Doppler can monitor for hypertension. If available an ultrasound is the best way to confirm the diagnosis of cardiomyopathy.

Treatment will vary according to the form of cardiomyopathy and the level of risk indicated. The dilated form may require medication to improve the strength of heart muscles and to remove excess fluid. A low-salt diet is usually necessary to reduce sodium levels and water retention. At times, excess fluid must be removed manually by the vet.

HCM and restricted forms of cardiomyopathy require medication to relax the ventricle muscle and improve heart function and blood flow. Diuretics and a low-salt diet will help remove excess fluids, and drugs to dissolve clots and control rhythmic irregularities are often prescribed.

With early detection, a faithful regimen of medication and special diet can slow the process of heart disease and allow your pet to enjoy a period of relatively good health and comfort.

Diane L. Jarvis is educ