Feline Hypertrophic Cardiomyopathy (HCM)

Feline Hypertrophic Cardiomyopathy (HCM) is a common and serious heart disease that affects cats, particularly certain breeds like Maine Coons, Ragdolls, and Bengals. It is characterized by the abnormal thickening (hypertrophy) of the heart muscles, especially the walls of the left ventricle, the main pumping chamber of the heart. This thickening reduces the chamber's capacity to hold blood, leading to difficulties in pumping blood effectively. As a result, the heart has to work harder to maintain normal circulation, which can lead to various complications.


Heart Murmurs: A veterinarian may detect abnormal heart sounds, known as heart murmurs, during a physical examination.

Respiratory Distress: Cats might experience difficulty breathing, rapid or labored breathing, or open-mouth breathing due to fluid buildup in the lungs (pulmonary edema).

Lethargy: Cats with HCM might show reduced energy levels and overall lethargy.

Coughing: Coughing could be observed, especially when fluid accumulates in the lungs.

Fainting or Collapse: In severe cases, cats might collapse or faint due to reduced blood supply to the brain.

Decreased Appetite and Weight Loss: Cats might lose their appetite and experience weight loss.


Treatment for feline HCM aims to manage symptoms, improve heart function, and enhance the cat's quality of life.

Medications: Veterinarians often prescribe medications to control heart rate, decrease blood pressure, and improve heart muscle function. Common medications include beta-blockers, calcium channel blockers, and ACE inhibitors.

Dietary Management: Specialized diets low in sodium and high in taurine (an essential amino acid for cats) can be recommended to support heart health.

Regular Monitoring: Cats with HCM require regular veterinary check-ups and monitoring of heart function through imaging techniques like echocardiography.

Fluid Management: In cases where fluid accumulates in the lungs, diuretics may be prescribed to reduce fluid buildup.

Surgery or Interventional Procedures: In certain severe cases, surgical procedures or interventions might be considered to alleviate specific issues.

Genetic Inheritance

Feline HCM is often considered to have a genetic component, especially in certain breeds. While the exact genetic mechanisms are not fully understood, it is believed to be caused by mutations in genes responsible for regulating the structure and function of heart muscle cells. These genetic mutations can be passed from one generation to the next.

However, it's important to note that not all cats with genetic predisposition will develop HCM, and not all cases of HCM are solely due to genetics. Environmental factors and other complex interactions can also contribute to the development of the disease.

Breeders and veterinarians work to minimize the risk of passing on these genetic mutations by careful breeding practices, genetic testing, and responsible selection of breeding pairs to reduce the prevalence of HCM within specific breeds.

Stages of HCM

Feline Hypertrophic Cardiomyopathy (HCM) can vary in severity and progression, leading to different levels or stages of the disease. These levels help veterinarians determine the appropriate treatment and management strategies. The severity of HCM is typically classified into three main levels:

It's important to note that HCM is a progressive disease, meaning it can worsen over time. Cats can move from one level to another if the disease progresses. Early detection and regular monitoring are crucial for managing HCM effectively and improving the cat's quality of life.

Veterinarians use diagnostic tools like echocardiography (ultrasound of the heart) to assess the thickness of heart muscles, measure heart chamber dimensions, and evaluate blood flow within the heart. These assessments help determine the stage of HCM and guide treatment decisions.

Regardless of the level of HCM, ongoing veterinary care and management strategies are essential to provide the best possible outcome for affected cats. Regular check-ups, medication administration, dietary adjustments, and a supportive environment can all contribute to improving the cat's well-being and extending their lifespan.

What tests assess and diagnose?

Veterinarians use several diagnostic tests to assess and diagnose Feline Hypertrophic Cardiomyopathy (HCM) in cats. These tests provide valuable information about the structure and function of the heart, helping veterinarians determine the presence and severity of the disease. Here are the main types of tests used for diagnosing HCM:

These diagnostic tests are often used in combination to obtain a comprehensive view of the cat's heart health. Echocardiography remains the cornerstone of HCM diagnosis because it provides detailed information about heart structure, thickness, and function. If HCM is diagnosed, veterinarians will work with the cat's owner to develop a tailored treatment plan that includes medication, dietary adjustments, and ongoing monitoring to manage the disease's progression and improve the cat's quality of life.