Companion Animals

Heart Murmurs in Cats: Welfare Implications and Management

Welfare guide for cat owners and vets on managing heart murmurs and underlying cardiac disease in cats.

Key Facts

Heart murmurs in cats are common and range from clinically insignificant to indicators of serious disease
Hypertrophic cardiomyopathy (HCM) is the most common underlying cause of significant cardiac murmurs in cats
Many cats with murmurs live normal lives for years — murmur grade does not directly correlate with disease severity
Cats with HCM are at risk of aortic thromboembolism — a devastating welfare emergency causing sudden paralysis and severe pain
Echocardiography is essential to differentiate significant from insignificant murmurs
Clopidogrel reduces the risk of thromboembolism in cats with moderate to severe HCM
Clinical signs of decompensation include open-mouth breathing, lethargy, and exercise intolerance
Some breeds — Maine Coon, Ragdoll, British Shorthair — have genetic predisposition to HCM

Welfare Significance

Cardiac murmurs in cats require proper investigation and monitoring. The welfare stakes are high: HCM-associated aortic thromboembolism is one of the most painful acute conditions in cats, and it can often be prevented with appropriate medication. Early echocardiographic diagnosis enables targeted prevention.

What You Can Do

Have cats with murmurs assessed by echocardiography by a veterinary cardiologist
Monitor cats with HCM for signs of cardiac decompensation
Discuss antiplatelet therapy with your vet for cats with moderate to severe HCM
Breed from HCM-clear individuals in predisposed breeds — use DNA testing where available