other disease Cat

Feline hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is the most common heart disease in cats. The muscular wall of the left ventricle thickens: the cavity it surrounds becomes smaller and fills less well with blood. The heart compensates for a long time. Many cats...

Find a veterinarian All cat diseases

Definition Signs Causes Diagnosis Treatment Prevention Complications When to see a vet Prognosis FAQ Sources Affected species

What is it?

Hypertrophic cardiomyopathy is the most common heart disease in cats. The muscular wall of the left ventricle thickens: the cavity it surrounds becomes smaller and fills less well with blood.

The heart compensates for a long time. Many cats live for years without the slightest sign, and the disease is discovered by chance, during a routine examination or assessment before anesthesia.

When signs appear, they most often reflect a complication already present. This is why screening is so important in this disease.

Commonly observed signs

These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.

Related signs — each one links to its page:

Difficulty breathing Rapid breathing Fatigue Reduction Loss of appetite

For a long time, no visible signs: this is the particularity of this disease.

Rapid breathing at rest or during sleep, then visible effort to breathe, sometimes mouth open.

Unusual fatigue, refusal to play, cat hiding or remaining still.

Loss of appetite and depression.

Sudden and painful paralysis of the hindquarters indicates the migration of a clot: it is an absolute emergency.

Cats rarely cough in cases of heart disease, unlike dogs: the absence of cough should never be reassuring.

In some cases, the first sign is discomfort or sudden death in an animal that appeared well.

When to consult without delay

This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.

Causes and risk factors

In most cases, the heart muscle thickens without external cause: it is a disease of the muscle itself.

In several breeds, genetic mutations transmitted by parents have been identified and can be detected by a test.

Other diseases can thicken the heart without being a true cardiomyopathy: hyperthyroidism in older cats, high blood pressure, kidney disease, acromegaly. The veterinarian systematically looks for them, because they can be treated and the heart can then improve.

Breed: the Maine Coon and Ragdoll have identified genetic mutations; the Persian, British Shorthair, Sphynx, Bengal and Norwegian are also over-represented. The alley cat is not spared.

Sex: males are more often affected, and often younger.

Age: the disease can occur in young adults as well as in older cats; there is no age safe.

A heart murmur, irregular rhythm or galloping sound heard on auscultation warrants a thorough examination, even in a cat that is well.

Diagnosis and care

Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.

The veterinarian auscultates the heart and lungs, counts the heart and respiratory rates and measures the blood pressure.

Cardiac ultrasound is the reference examination: it alone measures the thickness of the muscle and the condition of the cavities. A breath is neither essential nor sufficient to make the diagnosis — affected cats have no breath, healthy cats have one.

A blood test evaluates the thyroid in older cats and the kidneys; a cardiac blood marker can help sort which cats to prioritize for exploration.

Chest x-rays are useful when the cat is breathing poorly, to look for fluid around the lungs.

A cat in respiratory distress is first placed on oxygen and left to calm down: examinations wait until it is better, because handling is dangerous at this stage.

Treatment

No treatment makes the thickening of the muscle disappear. The objective is to protect the cat from complications and preserve its comfort.

A cat without any signs sometimes receives no medication: regular ultrasound monitoring is sufficient, and this is a medical decision in its own right.

In the event of heart failure, diuretics evacuate the fluid accumulated around the lungs: they are the basis of the treatment of attacks.

Medicines that slow down the heart or make it easier to fill are used depending on the form of the disease.

When the risk of a clot is considered high, long-term antiplatelet or anticoagulant treatment is prescribed.

Any cardiac treatment for cats must be adjusted and reassessed by the veterinarian. Never any adjustment at home, never any human medication: many are toxic to the cat.

Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.

Prevention

The disease cannot be avoided, but it can be detected.

For the breeds concerned, a genetic test exists for certain mutations and a cardiac ultrasound before breeding is recommended; serious breeders practice them and communicate the results.

Auscultation at each annual visit, and an ultrasound before any anesthesia in a cat at risk, avoid accidents.

At home, counting the sleeping cat's respiratory rate once a week is a simple and reliable way to spot a worsening: breathing that clearly accelerates at rest should lead to a consultation.

Possible complications

Heart failure: Fluid builds up in or around the lungs and the cat suffocates.

Aortic thromboembolism: a clot formed in the heart blocks circulation to the hindquarters and causes sudden, very painful paralysis.

Heart rhythm disorders, sometimes responsible for discomfort or sudden death.

These complications can occur in a cat that appeared perfectly healthy the day before: this is what makes screening useful.

When to see a veterinarian

Your cat is breathing quickly at rest or while sleeping, or is visibly struggling to breathe: emergency.

He is breathing with his mouth open, his gums are pale or bluish: absolute emergency.

He can no longer use his back legs and cries out in pain: absolute emergency.

He gets tired quickly, hides, eats less.

Your veterinarian has heard an abnormal murmur or rhythm: make an appointment for an ultrasound without waiting for signs to appear.

Your cat belongs to a predisposed breed and must be anesthetized: discuss this before the procedure.

Prognosis

The development varies greatly from one cat to another. A cat detected early, without complications, can live for many years with a good quality of life under simple supervision.

The appearance of heart failure or a clot significantly darkens the prognosis.

The regularity of ultrasound monitoring, more than the severity observed at diagnosis, guides decisions and makes it possible to anticipate complications.

Frequently asked questions

My cat has a heart murmur: is he necessarily sick?

No. Many wheezes in cats are without consequence, and conversely an affected cat may have no wheezes at all. Only cardiac ultrasound can make a decision.

How do I monitor my cat at home?

By counting the movements of his ribcage while he sleeps, once a week, always in the same conditions. A clear and lasting acceleration at rest justifies a rapid consultation.

Should you change your diet?

There is no food that treats this disease. A low-salt diet may be recommended in cases of heart failure, but only on the veterinarian's indication: a cat refusing to eat is a more serious problem than excess salt.

My cat needs surgery: is there an additional risk?

Yes, anesthesia and infusions put a strain on an already limited heart. Always report the illness before an intervention: the protocol and monitoring are adapted accordingly.