猫の肥大型心筋症（HCM）
HCMは猫に最も多い心臓病です。スクリーニングによる早期発見は猫の寿命を数年延ばせる可能性があります。
Hypertrophic cardiomyopathy (HCM) causes the walls of the heart to thicken, reducing its ability to pump blood effectively. It affects up to 15% of all cats and is the leading cause of sudden death in young, apparently healthy cats. Screening with echocardiography is the only way to detect HCM before symptoms appear. RVC offers cardiac screening for at-risk breeds.
- HCM is the most common heart disease in cats
- Thick heart walls reduce pumping efficiency and can cause blood clots
- Often asymptomatic until advanced — screening is critical
- Genetic predisposition in Maine Coons, Ragdolls, and British Shorthairs
- Diagnosis requires echocardiogram — X-rays and stethoscope are insufficient
- Medication can slow progression and manage symptoms
What is HCM?
In HCM, the muscle walls of the left ventricle thicken abnormally, reducing chamber size. The heart must work harder to pump blood. Over time, this leads to heart failure, arrhythmias, and blood clot formation (thromboembolism). A clot traveling to the hind legs causes sudden paralysis — a devastating, painful emergency. Some cats with severe HCM die suddenly with no prior symptoms.
At-Risk Breeds and Genetics
While any cat can develop HCM, certain breeds have genetic mutations that increase risk: Maine Coon (MYBPC3 mutation), Ragdoll (same mutation), British Shorthair, Sphynx, Norwegian Forest Cat, and Bengal. However, most cats with HCM are mixed-breed — genetics is only one piece of the puzzle. Cats as young as 6 months can develop HCM, though it's more common in middle-aged and older cats.
Symptoms and Diagnosis
Early HCM has no symptoms — this is why screening matters. As the disease progresses, signs include: difficulty breathing (from fluid in lungs), lethargy and reduced activity, sudden hind leg paralysis (saddle thrombus), fainting, and sudden death. A heart murmur may be heard on physical exam, but not all cats with HCM have murmurs. Definitive diagnosis requires an echocardiogram (heart ultrasound) by a veterinarian experienced in cardiac imaging.
Management and Prognosis
There is no cure for HCM, but treatment improves quality of life and longevity. Medications include: beta-blockers (atenolol) to slow heart rate and reduce workload, ACE inhibitors to manage blood pressure, diuretics (furosemide) for fluid in lungs, and anticoagulants (clopidogrel) to reduce clot risk. Low-sodium diets may help. Regular echocardiograms every 6-12 months monitor progression. With early detection and proper management, many cats live years with good quality of life.
- Any heart murmur detected on routine exam
- Difficulty breathing or open-mouth breathing
- Sudden paralysis of hind legs (EMERGENCY)
- Lethargy or reduced activity in a previously active cat
- Fainting or collapsing
- Annual screening for at-risk breeds starting at age 1
RVC
RVC provides feline cardiac screening with echocardiography. If your cat is an at-risk breed, has a heart murmur, or shows any cardiac symptoms, schedule an evaluation at +853 6677 6611.
+853 6677 6611