Screening Cats With Murmurs for Cardiac Disease

In the Literature

Carter R, Partington C, Matos JN. Accuracy of combined signalment, physical examination and cardiac biomarkers in screening cats with asymptomatic murmurs for cardiac disease. J Vet Intern Med. 2026;40(1):aalaf037. doi:10.1093/jvimsj/aalaf037

The Research …

Heart murmurs in cats are not a completely reliable indicator of clinically important heart disease; benign murmurs are reported in 12% to 41% of healthy cats.^1,2 Murmurs detected in apparently healthy cats have a positive predictive value of only 30% for hypertrophic cardiomyopathy, the most common heart disease in cats.² In ≈33% of affected cats, hypertrophic cardiomyopathy leads to congestive heart failure, arterial thromboembolism, or sudden death.^3-5 Ideally, early detection of hypertrophic cardiomyopathy in cats should trigger interventions to reduce the risk for life-threatening complications.⁶ Echocardiography is the diagnostic standard for cardiomyopathy but is not always feasible.

This single-center, cross-sectional study assessed the diagnostic accuracy of previously known cardiac disease risk factors based on signalment, physical examination, and cardiac biomarker variables to detect clinically significant cardiomyopathy and aid decision-making regarding value of pursuing echocardiography in cats with subclinical heart murmurs.

Client-owned cats (n = 202) with a median age of 7.1 years were included in this study; cats with clinical signs of heart disease, systemic hypertension, hyperthyroidism, or anemia were excluded. Echocardiography was performed in all cats, and 123 cats (60.9%) were diagnosed with clinically significant cardiac disease. There was no difference in age, breed, or sex between normal cats and those with cardiac disease. Cats with cardiac disease were heavier, were more likely to be overweight (BCS ≥6/9), had louder murmurs (≥3/6), and had significantly higher concentrations of N-terminal pro-brain natriuretic peptide (NT-proBNP; 136 pmol/L [interquartile range, 54-467 pmol/L] vs 57 pmol/L [interquartile range, 37-95 pmol/L]), as well as high-sensitivity cardiac troponin 1 (0.086 ng/mL [interquartile range, 0.035-0.183 ng/mL] vs 0.027 ng/mL [interquartile range, 0.009-0.121 ng/mL]), compared with healthy cats. Multivariable logistic regression identified 4 risk factors: male sex, BCS ≥6/9, murmur grade ≥3/6, and NT-proBNP ≥109 pmol/L. Probability of cardiac disease in a cat with a murmur was <50% if the cat had ≤1 risk factor and >50% if the cat had ≥2 risk factors.

… The Takeaways

Key pearls to put into practice:

• In the present study, multivariable logistic regression determined that certain risk factors were independently associated with the odds of having cardiac disease. NT-proBNP ≥109 pmol/L, BCS ≥6/9, murmur grade ≥3/6, and male sex were independently associated with increased likelihood of cardiac disease in cats with subclinical heart murmurs.

• Sensitivity and specificity of identifying cardiac disease in cats increases with the number of criteria fulfilled. For example, the clinical importance of increased NT-proBNP concentration in a cat with a heart murmur is increased if any additional risk factors are present.

• Considering multiple risk factors can result in a higher likelihood of detecting underlying cardiac disease and can help guide subsequent diagnostic plans.