Heart disease develops in cats due to damage to the normal heart muscle, which leads to abnormal heart function. The cause of damage is often unknown, but it can be due to genetics, lifestyle (weight, exercise, diet, etc.), or from a primary problem elsewhere in the body that can also affect the heart. For example, conditions such as thyroid disease, kidney disease, and anemia can all affect heart function in cats.
The most common heart disease we see in cats is hypertrophic cardiomyopathy (HCM). This disease causes enlargement or thickening of the heart muscle itself. The impact of the thickening can be variable and affect heart function differently in each cat. Some cats remain asymptomatic for life if the thickening is very mild or focal. If the thickening is severe, though, this part of the heart may have a hard time expanding. This can lead to increased pressure within the heart itself or even fluid buildup into or around the lungs, which is a sign of congestive heart failure.
The symptoms of heart disease in cats include decreased appetite, hiding, weight loss, lethargy, open-mouth breathing, sudden collapse and/or increased respiratory effort. Also, some cats with heart disease do not have an underlying heart murmur and may exhibit no symptoms until they are in heart failure.
So, how do we detect and diagnose heart disease in cats? It is very important that cats are seen on an annual basis for an exam. Even if a murmur is not detected at that time, discussing behaviors at home, like diet, activity level, and litter box habits are key to detecting if a further workup is needed. Another important test is blood work.
The blood work recommended and performed at CVH not only monitors kidney, liver and thyroid function but includes something called a proBNP. This blood test will help identify asymptomatic cats with heart disease. Elevated protein levels indicate that heart disease may be present and referral for further work-up is needed. Ask us about this blood work at your cat’s next annual exam!