Disease Guide ·Heart Murmur ·2026

Heart Murmur in Cats — symptoms, vet costs & insurance

Up to 15% of apparently healthy cats have a heart murmur — but not all lead to serious disease. Most are caused by hypertrophic cardiomyopathy (HCM). An echocardiogram ($400-$800) determines whether a murmur indicates structural disease or is harmless.

By Marcel Janik · Reviewed by veterinary data
Veterinary cardiologist examining a cat with heart murmur using echocardiogram
Heart murmur in cats — real vet costs and insurance guide.

Contents

  1. 01 Key Facts & Real Vet Costs
  2. 02 The Real Cost
  3. 03 Insurance Traps
  4. 04 Common Questions
01/04
Key Facts & Real Vet Costs

What Causes a Heart Murmur

A heart murmur is abnormal sound from turbulent blood flow. Most common: hypertrophic cardiomyopathy (HCM) — abnormal heart muscle thickening. Physiological (innocent) murmurs in young kittens carry no clinical significance. Other causes: hyperthyroidism, anemia, hypertension. Murmur grade (I-VI) does not always predict disease severity.

Symptoms — Often None Initially

Many cats show no symptoms for years. When disease progresses: labored breathing, open-mouth breathing (emergency), reduced exercise, sudden hind limb paralysis (aortic thromboembolism), weight loss, lethargy. Sudden death can be the first sign in severe HCM. Cats hide illness well.

Diagnosis — $400-$900

Echocardiogram (heart ultrasound): $400-$800 — gold standard for structure and function. Chest X-rays: $150-$300. Blood panel: $100-$200 for thyroid and other conditions. NT-proBNP test ($50-$100) flags significant disease. Cardiologist-performed echocardiogram is ideal.

Treatment — $0-$200/Month

Innocent murmurs: no treatment. Mild HCM: monitoring every 6-12 months. Moderate-severe: atenolol or diltiazem ($15-$40/month); clopidogrel ($15-$30/month) to prevent clots. Heart failure: furosemide diuretic ($10-$20/month). Aortic thromboembolism emergency: $1,500-$3,000 hospitalization.

Total Cost — Variable

Innocent murmur: just monitoring. HCM management: $600-$1,200/year for medications and rechecks. Congestive heart failure or ATE: $2,000-$5,000+ acute costs.

Breed Risk — Maine Coon, Ragdoll

Maine Coons, Ragdolls, and British Shorthairs have highest HCM prevalence. Genetic testing available for Maine Coons and Ragdolls (MYBPC3 mutation).

Prognosis — Highly Variable

Innocent murmurs: excellent. Mild HCM with no symptoms: years of normal life. HCM with congestive heart failure: median survival 9-18 months. Aortic thromboembolism: guarded, 50% survive the acute episode.

Monitoring & Prevention

Breed-specific genetic tests for HCM mutations (Maine Coon, Ragdoll). Annual cardiac screening for at-risk breeds. Echocardiograms every 1-2 years for diagnosed HCM. Early detection before symptoms appear.

02/04

The Real Cost

Echo + annual monitoring for mild-moderate HCM.

Echocardiogram$400-$800 Annual medications$200-$600 Emergency (CHF/ATE)$2,000-$5,000
$600typical annual cost
03/04
Insurance Traps Heart murmurs and HCM are common reasons pet insurance claims are disputed.
Red flag · Exclusion

Coverage Basics

HCM is covered by most policies if enrolled before cardiac findings. Coverage includes echocardiograms, medications, X-rays, and emergency care. Cardiac emergencies can cost $3,000-$5,000.

Red flag · Pre-existing

The Murmur Pre-Existing Trap

Murmurs detected before enrollment — even soft or innocent ones — may exclude entire cardiac coverage. Insurers deny claims as pre-existing using routine records. Enroll before any murmur is documented.

Red flag · Breed

Breed-Specific Exclusions

Some insurers exclude heritable conditions in high-risk breeds. Maine Coons and Ragdolls may face HCM exclusions or require negative genetic test proof. Some policies exclude conditions breeds are 'predisposed to' — HCM qualifies.

Red flag · Waiting period

Cardiac Waiting Period

Some insurers apply longer waiting periods (30-180 days) for cardiac conditions. Heart failure claims shortly after enrollment may be denied due to extended waiting period. Check cardiac-specific waiting periods, not just 14-day illness period.

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04/04
Common Questions Real answers about heart murmur diagnosis, HCM, and insurance coverage.
0What causes heart murmurs in cats?
Most common: hypertrophic cardiomyopathy (HCM), heart muscle thickening. Physiological (innocent) murmurs occur in young kittens and healthy cats from turbulent flow. Other causes: hyperthyroidism, anemia, high blood pressure, congenital defects. Echocardiogram distinguishes HCM from innocent murmurs.
1How serious is a heart murmur in cats?
Depends on cause. Innocent murmurs require only monitoring. HCM ranges mild (years of normal life) to severe (heart failure, blood clots). Murmur grade (I-VI) doesn't predict severity reliably. Grade II can indicate significant disease; grade V may be less important. Only echocardiography assesses severity.
2Do cats with heart murmurs need treatment?
Not always. Innocent murmurs need no treatment, only monitoring. Mild HCM needs echocardiograms every 6-12 months. Medication starts when HCM progresses or symptoms develop: atenolol or diltiazem (slow heart rate), clopidogrel (prevent clots). Heart failure needs furosemide diuretic.
3How much does it cost to evaluate a heart murmur in a cat?
Echocardiogram: $400-$800. Chest X-rays: $150-$300. Blood work with thyroid: $100-$200. NT-proBNP test: $50-$100. Total workup at specialty center: $600-$1,200.
4What is aortic thromboembolism (ATE) in cats?
ATE ('saddle thrombus') is a blood clot at aortic bifurcation cutting blood supply to hind legs. Sudden onset: cat suddenly can't use hind legs, in extreme pain, legs feel cold. Survival ~50% with aggressive treatment. Clopidogrel reduces clot risk in advanced HCM.
5Which cat breeds are most prone to heart murmurs and HCM?
Maine Coons and Ragdolls have highest HCM prevalence from MYBPC3 genetic mutations. British Shorthairs, Persians, Sphynx, Norwegian Forest, Scottish Folds also at risk. Genetic testing available for Maine Coons (A31P) and Ragdolls (R820W) to identify carriers.
6How is HCM different from other heart diseases in cats?
HCM: heart muscle thickens abnormally, reducing chamber volume and filling. Dilated cardiomyopathy (DCM): heart weakens and dilates, historically from taurine deficiency, now rare. Other forms: restrictive cardiomyopathy (RCM) and unclassified cardiomyopathy.
7Does pet insurance cover heart murmurs in cats?
Most policies cover HCM if enrolled before cardiac signs documented. Key trap: murmurs noted at routine exams before enrollment exclude all cardiac as pre-existing. Some policies extend waiting periods (30-180 days) for cardiac. Enroll before any heart murmur is documented.

Sources

  1. Paige CF, Abbott JA, Elvinger F, Pyle RL. Prevalence of cardiomyopathy in apparently healthy cats. J Am Vet Med Assoc. 2009;234(11):1398-403.
  2. Fox PR, Keene BW, Lamb K, Schober K, Chetboul V, Fuentes VL, Boswood A. International collaborative study to assess cardiovascular risk and evaluate long-term health in cats with preclinical hypertrophic cardiomyopathy and apparently healthy cats: The REVEAL Study. J Vet Intern Med. 2018;32(3):930-943.
Marcel Janik, founder of RealVetCost

I'm a dog owner who got burned

My mother-in-law took her German boxer to the veterinary emergency room — $1,200 in tests, no answers. A different vet solved it in minutes with $8 pills.

That moment stuck with me. When you're scared, you'll pay anything — and some vets price accordingly. I dug into vet costs and insurance. Confusing policies, buried exclusions, impossible to compare. So I built the resource I wish existed: real costs, real exclusions, plain language. Not here to sell you a policy. Here so you don't get blindsided.

Marcel Janik
Senior UX/UI designer