How to know if your cat suffers from a heart condition

The following article is extracted from the AnimalTalk website.

Although cancer is the leading cause of death in cats, heart failure (along with kidney failure, feline diabetes and AIDS) is also a major threat to our cats’ health. This first article in our new series on heart failure will focus on the causes and symptoms of heart failure in cats.Most heart disease in cats is hereditary, but cats of any age and any breed can develop it over time due to a variety of causes. Most cases are not linked to lifestyle, diet or home care. Unfortunately, cardiomyopathy (diseases of the heart muscle) is progressive. The early symptoms can be subtle, so it's important to know what to look for in order to detect heart failure as soon as possible. If you miss those symptoms, the cat will develop more apparent problems as the heart failure progresses and takes a heavier toll on her body. 

Heart failure is a condition caused by an abnormality in the structure or the function of the heart, in which it is unable to pump normal quantities of blood to the tissues of the body, depriving its organs and tissues of oxygen and nutrients. This leads to retention of fluids in the cat’s lungs and various body cavities. When heart failure reaches that point, the cat will start to show some distinct symptoms. 

Most cases of heart failure are associated with accumulation of fluid (oedema) in the lungs, the chest cavity (pleural effusion), or the abdominal cavity (ascites). This fluid accumulation can lead to shortness of breath and other problems such as coughing and difficulty breathing. Some of the symptoms of heart failure, and the progression of heart failure, are related to increased activity of the nervous system and to increased concentrations of circulating hormones (and related chemicals).

There are a wide variety of causes for heart failure in cats. Some of the most common are: 
Birth (congenital) defects of the heart 
Degeneration of the heart valves
Heart muscle disease (cardiomyopathy)
Diseases of the pericardium (the lining around the heart)
Irregular electrical rhythms of the heart (arrhythmia)

The most common cause of congestive heart failure in cats is heart muscle disease (cardiomyopathy), though anaemia and uncontrolled hyperthyroidism can also lead to this problem. 

The early signs and symptoms of heart failure can be subtle. Signs include:
Shortness of breath
Difficulty breathing (dyspnoea) or rapid breathing
Decreased appetite and gradual weight loss 
Fatigue and lethargy

Some cats with heart disease suffer sudden paralysis of one or both hind legs. For others the first symptom is sudden death. As heart failure progresses in a cat and fluid builds up in the animal's body, the symptoms become more prominent. Some cats will have problems finding a comfortable sleeping position due to the fluid, so restlessness may show up as a late-stage symptom. Lethargy can increase to a point where the cat rarely moves except to eat or use the litter box. Eventually, the cat will even lose interest in eating.

Text by Yolanda Wessels, in association with Dr HJ Lategan