Feline Hypertrophic Cardiomyopathy (HCM) is a heart disease that affects cats. It is the most common heart disease in cats and occurs due to a thickening of the heart muscle, making it harder for the heart to pump blood effectively.
HCM affects cats of all breeds and ages, and it’s estimated to affect 1 in 7 cats. In this article, we will discuss the definition, prevalence, causes, symptoms, diagnosis, and treatment of feline hypertrophic cardiomyopathy.
Definition and Prevalence
Feline Hypertrophic Cardiomyopathy is a heart disease that occurs as a result of thickening of the heart muscle. It is a progressive disease that affects the heart’s ability to pump blood to the rest of the body.
This thickening of the heart muscle causes a reduction in the size of the heart chambers, leading to an increase in pressure within the heart. Feline Hypertrophic Cardiomyopathy is the most common heart disease in cats, and it accounts for up to 48% of all feline heart disease.
The prevalence of HCM varies across breeds, with the most commonly affected breeds being the Maine Coon, the Ragdoll, and the British Shorthair. It is also a familial disease, and therefore, it is seen more commonly in certain pedigrees.
Causes and Symptoms
HCM in cats has a genetic basis, though the exact genetic mutation is still unknown. Researches suggest that there might be a genetic mutation in one or more genes that regulate the contraction and relaxation of the heart muscle cells.
The mode of inheritance is autosomal dominant, implying that cats carrying an HCM gene have a 50% chance of transmitting it to their offspring. Heart murmur is the most common symptom of HCM in cats and can be detected during a routine physical examination.
Other symptoms of HCM include lethargy, weakness, coughing, respiratory distress, and decreased ability to exercise. HCM in cats can also lead to the formation of blood clots, which can cause thromboembolism.
Blood clots can form in the diseased heart chamber, particularly at the level of the left atrium, and then lodge in the vasculature of various organs. The most commonly affected area is the hind legs, which can lead to paralysis.
Thromboembolism is a life-threatening condition that requires urgent medical attention. Some cats with hypertrophic cardiomyopathy may not show any clinical signs, and the disease may only be detected during routine screening or echocardiography.
Diagnosis and Treatment
Diagnosing HCM in cats requires a comprehensive evaluation of the cat’s medical history, physical examination, electrocardiogram (ECG), and echocardiogram. Echocardiography is the gold standard for the diagnosis of HCM in cats and provides a detailed image of the heart’s size and function.
The treatment of feline hypertrophic cardiomyopathy focuses on managing the condition’s clinical signs and preventing complications.
Medications such as diuretics, clopidogrel, and beta-blockers can be used to manage the symptoms of heart failure, including fluid buildup and shortness of breath.
Cats with HCM and a history of thromboembolism should receive long-term anti-coagulation therapy. The drug of choice is clopidogrel, which inhibits platelet aggregation and reduces the risk of blood clots.
Some cats with hypertrophic cardiomyopathy may require a surgical intervention, such as implantation of a pacemaker or defibrillator, if they develop severe arrhythmias. In conclusion, feline hypertrophic cardiomyopathy is a common heart disease in cats that results from a genetic mutation.
The disease presents with a variety of clinical signs, including heart murmurs, lethargy, respiratory distress, and thromboembolic events. Diagnosis is by echocardiography, and treatment aims to manage the clinical signs and prevent complications.
An early diagnosis and appropriate management can lead to a substantial improvement in the cat’s quality of life.
3) Stages of HCM in Cats
Feline Hypertrophic Cardiomyopathy (HCM) is a progressive disease that affects the structure and function of the heart. The disease develops gradually, often without clinical signs in the beginning stages.
The undiagnosed phase of HCM begins with the thickening of the heart muscle. Since cats are good at hiding their symptoms, it can be difficult for owners to identify that their cat has HCM in the early stages.
As the heart muscle continues to thicken, the heart’s chambers become smaller, causing an increase in pressure within the heart. This pressure can make it harder for the heart to pump blood throughout the body, leading to heart failure.
The severity of HCM can vary depending on the progression of the disease. In the early stages, the disease may be asymptomatic, and the cat may appear normal.
However, as the disease progresses, symptoms such as lethargy, weakness, decreased appetite, and rapid breathing may appear. If left untreated, feline hypertrophic cardiomyopathy may progress to a severe disease.
In the later stages, cats may develop heart failure, thromboembolism, and arrhythmias, which can be life-threatening. Heart failure is a condition that occurs when the heart can no longer pump blood effectively to meet the body’s needs.
As HCM progresses, the heart muscle thickens, causing significant structural changes to the heart. These changes can lead to increased pressure in the heart and fluid buildup in the lungs and other parts of the body.
Heart failure can be managed with medications such as diuretics, ACE inhibitors, and beta-blockers. Thromboembolism is another complication that can develop as HCM progresses.
Blood clots can form in the diseased heart chamber and obstruct the flow of blood to the rest of the body. Cats with HCM are at an increased risk of developing aortic thromboembolism, which is a serious medical condition that can cause hind limb paralysis and loss of blood flow to internal organs.
4) Diagnosing HCM in Cats
Diagnosing feline hypertrophic cardiomyopathy requires a thorough evaluation of the cat’s medical history, physical examination, and specialized diagnostic tests.
Physical Examination and Screening Tests
During a physical examination, the veterinarian will listen to the cat’s heart to detect any abnormalities such as heart murmurs or a rapid heartbeat. The veterinarian may also perform X-rays and an electrocardiogram (ECG) to identify any structural or electrical abnormalities in the heart.
Specialized Testing
If the veterinarian suspects that a cat has HCM, the following specialized tests may be recommended:
Hyperthyroidism and Elevated Blood Pressure: Elevated thyroid hormone levels and high blood pressure can cause thickening of the heart muscle similar to HCM. Therefore, routine blood work should be performed to evaluate thyroid hormone levels and blood pressure.
Echocardiography: Echocardiography is a non-invasive imaging technique that uses sound waves to visualize the structures and function of the heart. Echocardiography is the gold standard for diagnosing HCM because it can provide a detailed picture of the heart size and shape.
Genetic Testing: Genetic testing is available for some breeds with a predisposition for HCM. Genetic testing can identify whether a cat has a mutation in the genes that lead to HCM.
A positive genetic test result increases the risk of developing HCM, and therefore, the cat must be monitored closely for clinical signs. In conclusion, diagnosing feline hypertrophic cardiomyopathy requires a comprehensive evaluation of the cat’s medical history, physical examination, and specialized diagnostic tests.
HCM is a progressive disease that can result in heart failure, thromboembolism, and arrhythmias, with the later stages of the disease being severe. By diagnosing and managing HCM early, cat owners can ensure their feline friends live long, healthy lives.
5) How to Treat Feline HCM
Feline Hypertrophic Cardiomyopathy (HCM) is a serious heart condition that can lead to fatal complications such as heart failure and aortic thromboembolism. Treatment of HCM aims to manage clinical signs, improve the cat’s quality of life, treat congestive heart failure (CHF), prevent thromboembolism and arrhythmias.
Goals of Treatment
The goals of treating HCM in cats are to manage the clinical signs of the disease, improve the cat’s quality of life, and prevent or delay the progression of the disease. The treatment plan for each cat with HCM is tailored to their specific needs.
It may include lifestyle changes and medications to manage symptoms.
Medications
Medications can be used to manage the clinical signs of HCM, such as heart failure and thromboembolism. The most commonly used medications are as follows:
Diuretics: Diuretics help reduce excess fluid in the cat’s lungs and thoracic cavity.
They work by increasing the cat’s urine output and promoting fluid excretion. Furosemide is a commonly used diuretic in cats with HCM.
ACE-inhibitor: ACE inhibitors are a medication used to reduce the cat’s blood pressure and improve heart function. Enalapril and benazepril are commonly used ACE inhibitors in cats with HCM.
Pimobendan: Pimobendan is a medication that is used to manage congestive heart failure (CHF) in cats with HCM. It works by improving the heart’s ability to pump and improving oxygen delivery to the body.
Pimobendan is generally safe and well-tolerated in cats with HCM. Clopidogrel: Clopidogrel is an antiplatelet drug that helps prevent thromboembolism in cats with HCM.
It works by reducing the cat’s risk of developing blood clots. Clopidogrel is often used long-term to prevent thromboembolic events in cats with HCM.
Low Molecular Weight Heparin: Low molecular weight heparin is another medication used to prevent thromboembolic events. It works by preventing or reducing blood clots’ formation in the vessels.
However, its use in cats with HCM needs to be discussed with a veterinarian. Beta-blockers: Beta-blockers are a type of medication that helps to control the cat’s heart rate and to prevent arrhythmias.
Atenolol and metoprolol are commonly used beta-blockers in cats with HCM. Calcium Channel Blockers: Calcium channel blockers are medications that help to control heart rate, lower blood pressure, and manage arrhythmias.
Diltiazem is commonly used in cats with HCM.
General Cost to Manage HCM
The cost to manage Feline Hypertrophic Cardiomyopathy can be high. It is an expensive disease to diagnose initially, and ongoing monitoring and treatment can be expensive as well.
Cats with HCM may require hospitalization or emergency treatment for complications such as thromboembolism or CHF. The cost for these interventions can vary depending on the cat’s severity of the disease and the veterinarian’s fees.
6) How to Prevent HCM in Cats
Feline Hypertrophic Cardiomyopathy is a genetic disorder, and therefore, prevention involves breeding practices to reduce the prevalence of the disease. Breeders’ Role in Prevention
Breeders can help prevent HCM by screening their cats for the disease and removing cats with HCM from breeding.
Cat owners should always consider purchasing from a reputable breeder who performs genetic testing and echocardiography to screen for HCM. Genetic test: The genetic test can help identify cats with a mutation or mutations responsible for the development of HCM.
It is a simple and non-invasive process that involves taking a DNA sample and testing it for specific gene markers. Screening Echocardiography: Echocardiography is the most accurate diagnostic test for the diagnosis and monitoring of HCM in cats.
Screening echocardiography aims to detect HCM in cats before they develop clinical signs. Removing Cats with HCM from Breeding: Cats diagnosed with HCM should not be bred.
Offspring from cats diagnosed with HCM are at an increased risk of developing HCM. Predisposed breeds such as Maine Coons and Ragdolls have a higher risk of developing HCM.
Therefore, these breeds should be screened regularly to detect HCM before they develop clinical signs. In conclusion, the prevention and treatment of Feline Hypertrophic Cardiomyopathy require a comprehensive approach involving screening, diagnostic testing, and medication management.
Early detection, appropriate treatment, and ongoing monitoring are crucial in managing the disease and improving the cat’s quality of life. Breeders can also play a significant role in preventing HCM by screening their cats for the disease and removing cats with HCM from breeding.
Feline Hypertrophic Cardiomyopathy (HCM) is a progressive heart disease that affects cats of all breeds and ages. The disease results from a genetic mutation that causes thickening of the heart muscle, leading to a reduced ability of the heart to pump blood effectively.
HCM progresses gradually, and early detection and proper management are crucial to improving cats’ quality of life. Management of HCM includes medication management, lifestyle changes, and regular monitoring.
Additionally, breeders have a significant role to play in preventing HCM through genetic testing and screening for predisposed breeds such as Maine Coons and Ragdolls. Feline Hypertrophic Cardiomyopathy is a serious condition with significant implications, but with appropriate intervention, cats with HCM can live long, healthy lives.