Maine Coon HCM screening combines genetic testing with serial echocardiography, as genetic tests alone do not identify all affected cats. Echocardiography remains the only viable means to breed screen cats regardless of genotype, because known disease-causing mutations such as A31P do not account for all cases of hypertrophic cardiomyopathy (HCM) in the breed. Journal of Vete…
Genetic testing for the A31P mutation in cardiac myosin binding protein C (MYBPC3) stratifies cardiac death risk but does not replace echocardiographic phenotyping. Cats homozygous for A31P have an 80% prevalence of HCM and a 48% rate of cardiac death during follow-up, compared to significantly lower rates in heterozygous and wild-type cats. Journal of Vete… Heterozygous cats do not always show left ventricular (LV) hypertrophy, but the prevalence of hypertrophy increases with age, making serial echocardiographic monitoring essential in this genotype group. Journal of Vete…
Echocardiographic diagnosis of HCM is based on subjective impression supported by measurements — measurements alone are not diagnostic. Assessment of cardiac chamber size and wall thickness should be interpreted alongside the overall echocardiographic picture and other supportive findings. Journal of Vete… Body weight-normalized measurements are recommended because heart size in normal cats is dependent on body weight, and allometric scaling is the most accurate normalization method. Journal of Vete…
Speckle tracking echocardiography adds diagnostic value in preclinical and equivocal cases. The combination of LV mass, mitral annular plane systolic excursion of the free wall (MAPSE FW), and LV internal diameter in diastole (LVIDd) shows the best association with an HCM diagnosis. This combined model is particularly useful when hypertrophy is not obvious, such as in equivocal cases or cats with a family history of HCM. Journal of Vete… Longitudinal strain and MAPSE alongside LV mass are additional tools that can aid identification of HCM or improve monitoring beyond wall thickness alone. Journal of Vete…
ProANP (atrial natriuretic peptide precursor) is a useful adjunct biomarker for advanced HCM but is not sensitive enough for early screening. ProANP concentrations correlate with HCM severity and are significantly elevated in cats with confirmed HCM, but do not differ significantly between cats with equivocal echocardiographic findings and healthy cats. Polish Journal… ProANP also correlates with age (r = 0.5578) and, in affected cats, with ejection fraction (r = 0.5305) and end-systolic LV diameter (r = 0.48). Polish Journal… Cats with elevated ProANP should be referred for echocardiographic confirmation. Polish Journal…
Relaxation time assessment is a sensitive technique for HCM screening during the preclinical phase and can help identify cats at risk of developing HCM before overt hypertrophy is present. Veterinary World
| Tool | Role | Key Finding | Caveat |
|---|---|---|---|
| A31P genetic test | Risk stratification | Homozygotes: 80% HCM prevalence, 48% cardiac death Journal of Vete… | Does not identify all HCM cases Journal of Vete… |
| Standard echocardiography (wall thickness, LV mass, LVIDd) | Primary phenotypic diagnosis | Measurements support subjective impression Journal of Vete… | Measurements alone not diagnostic Journal of Vete… |
| Speckle tracking (MAPSE FW + LV mass + LVIDd) | Preclinical/equivocal cases | Best combined model for HCM diagnosis Journal of Vete… | Heterozygotes may lack hypertrophy early; prevalence increases with age Journal of Vete… |
| Relaxation time assessment | Preclinical screening | Sensitive in preclinical phase Veterinary World | — |
| ProANP | Advanced HCM adjunct | Elevated in confirmed HCM; not significant in equivocal cases Polish Journal… | Not useful for early-stage screening Polish Journal… |
Would you like guidance on the specific echocardiographic wall thickness cutoffs used to define HCM versus equivocal findings in cats?