A cat is not a small dog. Common heart diseases in cats are different in dogs. We already knew common acquired heart disease in dogs in the previous topic. They are degenerative and progressive diseases. Although the common acquired heart disease in cats are progressive, the nature of the development of the disease is slightly different than in dogs. The most common acquired heart disease in cats is hypertrophic cardiomyopathy (HCM). HCM is a genetic disease and causes the muscular wall of a heart to thicken, decreasing the heart’s efficacy and sometimes creating symptoms, like spiritless, decreased appetite, and open mouth breathing. The condition are more prevalent in certain breeds (including British Shorthair, Maine Coon, Exotic Shorthair, and Ragdoll).
The rate of increasing thickness of heart muscle may vary considerably and the onset time of muscle getting thickened is also different in each cat. For example, some cats may have normal left ventricle for a period of time and then suddenly become very thickened in 1 day. Others may have mild thickened left ventricle and never getting more thickened for many years. HCM can affect cats of all ages. Proper diagnosis and treatment can decrease the chance that a cat with HCM experiencing certain symptoms and can improve his or her quality of life.
The left ventricle is thickened in a cat with HCM, leading to a decrease in the volume of the heart chamber and to abnormal relaxation of the heart muscle. These changes cause increased oxygen usage and possibly to oxygen starvation of the heart muscle. This oxygen starvation may cause heart cells to die, worsening heart function and even the development of arrhythmia. In addition to these changes, less efficient blood pumping may result in congestive heart failure or/and the formation of blood clots in the heart.
Clinical signs of congestive heart failure are labored or rapid breathing, open mouth breathing, and lethargy. A serious and potentially life threatening consequence of HCM is the formation of blood clots in the heart. These blood clots may travel through the bloodstream and obstructs flow in other parts of the body. The effect of the clot depends on its location. In cats with HCM, clots most commonly result in blockage of blood flow to the hind limbs, causing acute hind limb pain and even hind limb paralysis. Although relatively rare, cats with HCM are at risk for sudden death. Diagnosing and treating the HCM properly can help decrease severity of the signs and may decrease the likelihood of blood clots.
The most commonly diagnosed congenital heart disease in cats are ventricular septal defect (VSD), patent ductus arteriosus (PDA), and mitral valve dysplasia (MVD). The pathophysiology of MVD is similar as MMVD in dogs but it’s the problem since birth. PDA in cats is as same as in dogs. VSD is a hole in the ventricular septum. The septum is a muscular tissue that separates the left and right ventricle and prevents blood being diverted from one chamber to the other. The severity of VSD depends on the size of the hole. A small VSD is commonly of no significance, and an affected kitten can be expected to live a normal life. A moderate or larger hole, may cause enough shunting of blood to produce clinical signs, such as rapid breathing and exercise intolerance.
If your pets are in an emergency or if you have general inquiries, please do not hesitate to contact Veterinary Emergency Centre.
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