Heart Disease Caused by Scarring of the Heart Muscles in Cats

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Restrictive Cardiomyopathy in Cats

A cat's heart is composed of four chambers: the top two chambers are the left and right atria and the bottom two chambers are the left and right ventricles. The valves of the heart are located between the left atrium and the left ventricle (the mitral valve), between the right atrium and the right ventricle (the tricuspid valve), from the left ventricle to the aorta (the main artery of the body, the valve of which is the aortic valve), and between the right ventricle to the main pulmonary artery (the pulmonary, or lung valve).


Cardiomyopathy is the medical term for disease of the heart muscle. Restrictive cardiomyopathy is a disease in which the muscle is stiff and does not expand, such that blood cannot fill the ventricles normally. Restrictive cardiomyopathy in cats is characterized by abnormal filling of the chambers of the heart (known as diastolic dysfunction), severe atrial enlargement, normal left ventricular wall thickness and variable abnormal pumping of the heart (known as systolic dysfunction). Scar tissue of the heart muscle layer may be present. Other heart-muscle disorders, including inflammatory or immune-mediated diseases, may also be present.


Symptoms and Types


  • Lethargy
  • Poor appetite and weight loss
  • Fainting
  • Impaired movement or paralysis
  • Some cats are asymptomatic
  • Difficult breathing
  • Fast breathing
  • Open mouth breathing
  • Pale mucous membranes
  • Abdominal distention




  • Unknown
  • Suspected:
    • Inflammation of the heart muscle
    • Inflammation of the heart muscle and inner lining of the heart
    • Parasites in the heart
    • Thickening of the heart muscle with a heart attack
    • Diffuse small vessel disease and other causes of inadequate oxygen to the heart




Your veterinarian will conduct a complete physical exam with a blood chemical profile, a complete blood count, an electrolyte panel and a urinalysis to rule out other causes of disease. will need to give a thorough history of your cat's health, onset of symptoms, and possible incidents that might have precipitated this condition.


Your veterinarian will also order an electrocardiogram to evaluate the electrical conductivity of the heart’s beat for abnormalities. X-rays and an echocardiogram are essential in assessing heart disease and its consequences. X-rays of the lungs should also be taken to check for fluid accumulation.




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