Dilated Cardiomyopathy in Cats: Causes and Outlook

Name: Dilated Cardiomyopathy in Cats: Causes and Outlook
Creator: Dr. Zubair Khalid

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-10-03

Dilated heart in cats, called dilated cardiomyopathy, is a rare disease in which the heart muscle becomes weak and the chambers stretch out, so the heart cannot pump blood well. Most cats with heart disease have a different condition, hypertrophic cardiomyopathy, which makes the heart wall thick instead of thin. Dilated cardiomyopathy in cats is uncommon today, largely because commercial cat foods now contain enough taurine, an amino acid the feline heart needs.

This article is educational and is not a substitute for veterinary diagnosis or treatment.

Quick Answer

Dilated cardiomyopathy (DCM) means a thin, weak, enlarged heart that pumps poorly, and it is much less common in cats than in dogs [1].
Taurine deficiency was once the leading cause in cats, and it is now rare in cats eating complete commercial diets [1].
Some cats develop a DCM phenotype from other causes, including certain heart infections, genetic traits, or diets high in pulses such as peas and lentils [2][3][4][5].
Diagnosis relies on echocardiography, which shows enlarged chambers and reduced contractility [6].
Outlook varies widely. Some cats improve with treatment and diet change, while others progress to congestive heart failure [2][5].

What Is a Dilated Heart in Cats?

Cardiomyopathy means a primary disease of the heart muscle itself, not a problem caused by another body system or a structural defect like a leaky valve [1]. Veterinarians group feline cardiomyopathies into several types, including dilated, hypertrophic, arrhythmogenic right ventricular, and restrictive cardiomyopathy [1]. When no specific type fits, the disease is called cardiomyopathy with a nonspecific phenotype [1].

In the dilated form, the left ventricle and often the right ventricle become enlarged and flabby. The muscular wall thins, and the heart loses its ability to squeeze blood forward. The atria, the upper chambers, often enlarge too as blood backs up behind the weak ventricle [6][7]. This backup can push fluid into the lungs or the chest and abdominal cavities, which is called congestive heart failure.

DCM in cats is not the same disease as DCM in dogs. In dogs, especially large breeds like Doberman Pinschers and Boxers, DCM is a well-known and relatively common problem with recognized breed predispositions [6]. In cats, the dilated phenotype is uncommon, and when it appears, veterinarians look harder for an underlying cause. Some cats have a genetic form, and others have a form tied to diet, infection, or another disease process [1][2][5].

If you want to understand how the dilated type compares with the more common thickened-heart form, see Hypertrophic Cardiomyopathy in Cats.

Signs Owners Notice

Cats are masters at hiding illness, and early heart disease often causes no obvious signs. When signs appear, they usually reflect heart failure or poor blood flow.

Common things you may see at home include:

Hiding, sleeping more, or tiring quickly
Fast or labored breathing, especially when resting
Open-mouth breathing or panting, which is never normal in a calm cat
Reduced appetite or weight loss
A distended belly from fluid buildup
Weakness, collapse, or sudden hind leg paralysis from a blood clot

On examination, a veterinarian may hear a soft systolic heart murmur, best heard at the left side of the chest [6]. A gallop sound, an extra heart sound that suggests a stiff or failing ventricle, can also be present, and it is often more obvious in cats than in dogs [6]. The pulse in the groin may feel weak, and an irregular rhythm with pulse deficits may be found [6]. Depending on which side of the heart is failing, the veterinarian may also find fluid in the abdomen, rapid breathing, difficulty breathing, or a cough [6].

A young kitten can even show a dilated phenotype. One 10-week-old Oriental Shorthair was referred for stunted growth, weight loss, trouble breathing, and low activity compared with her littermates, and testing confirmed a dilated cardiomyopathy phenotype with heart failure [4]. This shows that age alone does not rule the condition out.

Causes and Risk Factors

Taurine Deficiency

Taurine is an amino acid that cats cannot make in sufficient amounts, so they must get it from food. Decades ago, taurine deficiency was a major cause of dilated cardiomyopathy in cats, and it is the reason taurine is now added to commercial cat foods. Today, a cat eating a complete and balanced diet rarely becomes taurine deficient, and true taurine-responsive DCM is uncommon [1]. When a veterinarian identifies a disease process as the cause of the heart muscle weakness, it is described as a secondary myocardial disease, such as taurine-responsive dilated cardiomyopathy [1].

Diet and Pulses

In 2018, the FDA issued an alert about a possible link between dilated cardiomyopathy in dogs and cats and diets high in pulses such as peas, lentils, chickpeas, and beans [3]. One 11-year-old cat with severe DCM and heart failure had been eating cat foods high in pulses, yet her taurine levels were normal, so taurine deficiency was not the explanation [2]. Her signs improved after treatment and a diet change, and her heart measurements stayed fairly stable for over a year [2]. A separate comparison of heart tissue from cats with DCM found more abnormal cell structures in those eating high-pulse diets than in those eating low-pulse diets [3]. This does not prove that pulses cause DCM in every cat, and the exact mechanism is not well established in veterinary research.

Genetics and Breed

Some cardiomyopathies have an identified genetic mutation or are inherited traits [1]. A dilated phenotype has been reported in an Oriental Shorthair kitten and in an Exotic Shorthair cat, which suggests that breed and family lines can play a role in some cases [7][4]. The full list of genes involved in feline DCM is not well established.

Infection and Inflammation

Heart muscle inflammation from an infection can sometimes produce a dilated phenotype. A young cat with a dilated, poorly contracting heart tested positive for Bartonella antibodies, and her heart function improved after treatment for heart failure plus antibiotics [5]. Another cat with recurrent heart failure and heart muscle thickening improved after treatment that included several antibiotics [8]. These are individual reports, and the link between infection and reversible heart disease in cats is still being studied.

Other Causes

Any condition that damages the heart muscle can lead to a dilated phenotype. Your veterinarian will check thyroid status, blood counts, blood chemistry, and other tests to rule out secondary causes before calling the disease primary DCM [7].

How Dilated Cardiomyopathy in Cats Is Diagnosed

Physical Examination and History

Your veterinarian starts with a full exam, listening carefully to the heart and lungs and feeling the pulses. A murmur, a gallop sound, a weak pulse, or an irregular rhythm can all point toward heart disease [6]. Your description of breathing changes, appetite, and activity helps set the level of concern.

Echocardiography

Echocardiography, an ultrasound of the heart, is the best test to diagnose DCM definitively [6]. It shows whether the left atrium and left ventricle are dilated and whether contractility, the strength of the squeeze, is markedly decreased [6]. It also helps your veterinarian tell DCM apart from other cardiomyopathies, which matters because treatment and outlook differ. For a broader look at how these types are separated, see Feline Cardiomyopathy: Phenotype Differentiation and Treatment.

Other Tests

Your veterinarian may recommend:

Test	What it looks for
Chest X-rays	Heart size, fluid in the lungs, fluid around the lungs
ECG	Irregular rhythms such as ventricular premature complexes or atrial fibrillation [6]
Blood tests	Taurine levels, thyroid status, organ function, markers of heart muscle injury [7][2]
Infectious disease testing	Bartonella and other infections that can affect the heart [5]
Ultrasound of the chest or belly	Fluid in the chest or abdominal cavity [7][5]

An ECG can reveal abnormal rhythms, and certain rhythm patterns on a routine ECG can strongly suggest DCM in some dog breeds [6]. In cats, the rhythm findings are more variable, so echocardiography remains the central test.

Treatment Options

Treatment aims to help the heart pump, remove excess fluid, and prevent complications like blood clots. Your veterinarian calculates every dose from your cat's weight and current health, so no dose is listed here.

Common medications used in reported feline DCM cases include:

Furosemide, a diuretic that removes fluid from the lungs and body [7][2][5]
Pimobendan, which supports the heart's pumping strength [7][2][5]
Clopidogrel, an antiplatelet drug that lowers clot risk [7][2][5]
Rivaroxaban, an anticoagulant used in some cats with severe heart disease [7]
Antibiotics when an infection is suspected [5][8]

Diet matters too. If your cat has been eating a diet high in pulses, your veterinarian may recommend switching to a diet without them. In one case, the cat improved after the diet change alone, without taurine supplements, because her taurine levels were already normal [2]. If taurine deficiency is confirmed, supplementation is part of the plan, and your veterinarian will set the amount.

Cats in congestive heart failure may need oxygen, drainage of fluid from the chest or abdomen, and hospitalization for stabilization [7][5]. Some cats need this support more than once over the course of their illness.

Recovery, Outlook, and Long-Term Management

The outlook for a cat with a dilated heart depends on the cause, how early it is found, and how the cat responds to treatment. Some cats do improve.

In one reported case, a cat with severe DCM and heart failure responded to medication and a diet change, with clinical signs improving, a heart muscle injury marker falling, and echocardiographic measurements staying relatively stable for over a year [2]. That cat was eventually euthanized for worsening heart failure 374 days after diagnosis [2]. Another cat with a dilated phenotype and a Bartonella infection improved after heart failure treatment and antibiotics [5]. A cat with recurrent heart failure and heart muscle changes improved after treatment that included antibiotics [8].

Other cats do not respond. One cat with a dilated phenotype affecting all four heart chambers continued to decline despite furosemide, pimobendan, clopidogrel, and rivaroxaban, and was euthanized [7]. This range is why your veterinarian will want repeat visits and repeat echocardiograms instead of a single prediction at diagnosis.

Long-term management usually includes:

Giving medications on a strict schedule, every day
Monitoring breathing rate at home while your cat rests
Recheck exams and echocardiograms at intervals your veterinarian sets
Watching for clots, which can cause sudden hind leg paralysis
Keeping stress low and maintaining a healthy weight

If your cat has a different cardiomyopathy, the plan will look different. For screening and clot prevention in the thickened-heart form, see Hypertrophic Cardiomyopathy HCM in Cats: Screening, Clot Prevention and Care.

Prevention

You cannot prevent every case of DCM in cats, because some causes are genetic or unknown. You can lower some risks.

Feed a complete and balanced commercial cat diet that meets taurine requirements. If you cook for your cat or feed a boutique or grain-free diet heavy in peas, lentils, or chickpeas, talk with your veterinarian about whether it is appropriate [3]. Ask before making big diet changes, especially if your cat already has heart disease.

Keep routine wellness visits so your veterinarian can listen to the heart and catch a murmur early. If your cat has a breed or family history that concerns you, ask whether screening echocardiography makes sense. Treat infections promptly, and follow your veterinarian's advice on testing if heart disease is found [5].

Limitations and When to Contact a Veterinarian

No article can tell you what is happening in your individual cat. Only a veterinarian who examines your cat, reviews the echocardiogram, and runs the right tests can diagnose DCM and set treatment.

Contact your veterinarian the same day if you notice:

A resting breathing rate that is clearly higher than usual
Reduced appetite lasting more than a day
New lethargy or hiding
A new cough or mild exercise intolerance

Go to an emergency clinic now if you see:

Open-mouth breathing, panting, or obvious struggle to breathe
Sudden hind leg weakness, dragging, or paralysis, which can signal a blood clot
Collapse or fainting
A swollen, tight belly that appeared quickly
Blue or gray gums

Routine visits are appropriate for stable cats on heart medication, for recheck bloodwork, and for diet questions. If you are unsure which category fits, call your veterinarian and describe what you see.

Frequently Asked Questions

Is dilated cardiomyopathy common in cats?

No, it is uncommon. Hypertrophic cardiomyopathy is the most frequently diagnosed feline cardiomyopathy, and the dilated form is much rarer, especially since taurine was added to commercial cat foods [1].

Can a cat with a dilated heart recover?

Some cats improve, and a few improve a great deal. Reported cases have shown clinical improvement and stable heart measurements for over a year after treatment and diet change, while other cats continue to decline despite full treatment [7][2].

Does taurine still cause heart disease in cats?

It can, but it is now uncommon. Taurine deficiency was once a leading cause of DCM in cats, and complete commercial diets today generally prevent it [1]. Cats on unbalanced homemade diets or unusual diets remain at risk.

Can diet alone cause a dilated heart in cats?

Diet may contribute in some cats, particularly diets high in pulses, but the link is not fully understood. One cat with normal taurine levels improved after switching off a high-pulse diet along with heart medication [2].

How long can a cat live with dilated cardiomyopathy?

There is no single answer. Survival ranges from days to well over a year depending on the cause, the response to treatment, and how early the disease is found [7][2]. Your veterinarian can give you a better estimate after repeat evaluations.

References

Overview of Cardiomyopathy in Dogs and Cats - Circulatory System. Merck Veterinary Manual.
Dilated cardiomyopathy of possible dietary origin in a cat. Journal of veterinary cardiology : the official journal of the European Society of Veterinary Cardiology, 2024.
Ultrastructural differences in the myocardium of cats with dilated cardiomyopathy eating high- versus low-pulse diets. Ultrastructural pathology, 2026.
Dilated cardiomyopathy phenotype in a 10-week-old Oriental shorthair kitten. Journal of veterinary cardiology : the official journal of the European Society of Veterinary Cardiology, 2025.
Transient dilated cardiomyopathy phenotype and positive Bartonella serology in a cat. Journal of veterinary cardiology : the official journal of the European Society of Veterinary Cardiology, 2025.
Dilated Cardiomyopathy in Dogs and Cats - Circulatory System. Merck Veterinary Manual.
Dilated Cardiomyopathy Phenotype With Global (Four-Chamber) Involvement in a Cat: Echocardiographic, Pathological, Histopathological, and Immunohistochemical Findings. Case reports in veterinary medicine, 2026.
Recurrent transient myocardial thickening and congestive heart failure in a cat. Journal of veterinary cardiology : the official journal of the European Society of Veterinary Cardiology, 2026.