Mercy has hypertrophic cardiomyopathy (HCM). When we took Annie, Eddie and Mercy in for their wellness exams, we decided to run the IDEXX SDMA test for Mercy. He is 10 years old and we wanted to get an idea of his kidney function as well as how he is doing overall. We ran the test but the results were not what we expected! Mercy’s kidney health is perfect and in fact quite remarkable for a 10 year old cat. But the test also showed an abnormal Cardiopet proBNP. Mercy’s results show on the low side of high but enough to cause concern. NT-proBNP concentration is compatible with increased stretch and stress on the myocardium. To understand better and get a more accurate understanding of cardiac structure and function, echocardiography is recommended.
Hypertrophic Cardiomyopathy (HCM)
Mercy’s echocardiogram showed an early stage of hypertrophic cardiomyopathy (HCM). HCM is the most common heart disease in cats. The condition results in hypertrophy or thickening of the heart muscle which, in time, creates increased stiffness of the heart walls (muscle) resulting in poor cardiac function during the relaxation phase of the cardiac cycle (diastole). As this condition worsens, the thickened heart muscle can cause obstruction to blood flow leaving the heart via the aorta. This increases the effort needed to pump blood out of the heart during the contraction phase of the cardiac cycle (systole).
The Cause of Hypertrophic Cardiomyopathy (HCM)
HCM is thought to be an inherited disorder caused by a genetic mutation of the genes that control heart muscle growth. The HCM mutation is determined in the Maine Coon and Rag Doll breeds. The genetic defect has not been identified in other purebred or domestic types of cats. In humans, more than one genetic mutation has been identified as causing HCM so it is likely to be true for cats as well.
Symptoms of Hypertrophic Cardiomyopathy (HCM)
The symptoms of HCM vary depending on the degree of severity and perhaps on the different genetic mutations in individual cats. Cats are most often diagnosed when they have no symptoms but when a veterinarian detects a heart murmur or an irregular heart beat during a wellness exam. When symptoms arise, they may include signs of congestive heart failure.
- Increased respiratory rate
- Labored breathing
- Shortness of breath
- Appetite loss
- Change in behavior like hiding
- Sudden loss of one or more legs due to blood clots obstructing blood flow
- Fainting spells from an irregular heart rhythm
- Acute sudden death may occur without any symptoms.
Treatment of Hypertrophic Cardiomyopathy (HCM)
The treatment for cats with HCM vary with the severity of the condition at the time of detection. Current medications include drugs that slow the heart rate and improve relaxation of the heart (beta blockers or calcium channel blockers), drugs that thin the blood to prevent blood clots from forming (platelet inhibitors, anticoagulants), and diuretics to control abnormal fluid buildup. Your veterinarian will determine the best treatment based on your cat’s condition.
Mercy was not showing any signs of respiratory distress but the blood work showed signs of a heart issue. The results of the echo showed the beginning stages of HCM and the plan of care is to take atenolol
Atenolol is a beta-blocker that affects the blood flow through arteries and veins and is used to treat chest pain and high blood pressure. Mercy’s prescription is to take a 1/4 pill every 12 hours. Dr. Guinan thinks we caught this early, so there is a better chance the atenolol will help Mercy and might even keep the condition from worsening.
Wellness Exams are So Important
I know I keep repeating this, but if Mercy didn’t go for his wellness exam and the IDEXX SDMA panel, we wouldn’t know he was experiencing these health issues. Please take your cats in for their check ups and if your cat is getting a little older, think about running the IDEXX SDMA panel to check their wellness.
Thank you for all the kind words and prayers for Mercy. We really appreciate your kindness.