Understanding Diagnostic Testing for Feline HCM
Hypertrophic cardiomyopathy (HCM) is the most common form of heart disease in cats. It is characterized by abnormal thickening of the heart muscle, which can interfere with the heart’s ability to function effectively. Many cats with HCM show no outward signs of disease, particularly in the early stages, making diagnostic testing an important component of detection and management. Veterinarians use a variety of diagnostic tools to evaluate cats for HCM. Each test provides different information, and no single test is appropriate for every situation.
Echocardiography (Cardiac Ultrasound)
Echocardiography is a non-invasive ultrasound examination (uses sound waves) of the heart and is considered the best practice for diagnosing HCM in cats. This test allows direct visualization of heart wall thickness, chamber size, and overall heart function. It can identify both early and advanced disease and distinguish HCM from other cardiac conditions.
Pros include its high diagnostic accuracy and ability to detect disease before clinical signs appear. Limitations include cost, limited availability in some areas, and the need for specialized training to interpret results. Mild or early disease may still be challenging to classify in some cases.
Physical Examination and Heart Auscultation (listening to heart sounds)
During a routine veterinary exam, a veterinarian may listen for heart murmurs, gallop rhythms, or irregular heartbeats. While these findings can raise suspicion for heart disease, many cats with HCM have normal heart sounds. This method is widely available and low cost, but it cannot confirm or rule out HCM on its own. Auscultation should be considered a screening tool rather than a diagnostic test.
Thoracic Radiographs (Chest X-Rays)
Chest X-rays can be used to evaluate heart size and assess the lungs for fluid accumulation (a sign of advanced heart disease). They are particularly useful in cats with respiratory symptoms or suspected heart failure. However, X-rays cannot reliably detect early HCM, and a normal result does not exclude disease. Structural changes are inferred rather than directly visualized.
Blood Biomarkers (NT-proBNP)
Blood tests such as NT-proBNP measure markers (chemicals in the blood) associated with cardiac stress. These tests can help differentiate cardiac from non-cardiac causes of respiratory distress and may indicate an increased likelihood of underlying heart disease. They are minimally invasive and useful in certain clinical scenarios, but they are not specific for HCM. Abnormal results require follow-up testing, and normal results do not rule out disease.
Electrocardiography (ECG)
An ECG, sometimes known as EKG, measures the electrical activity of the heart and can detect abnormal heart rhythms. While helpful for identifying arrhythmias, it does not assess heart structure and has a limited role in diagnosing HCM. Arrhythmias may have other causes besides HCM, and not all cats with HCM develop an arrhythmia.
Genetic Testing
Genetic testing is available for certain breeds with known HCM-associated mutations. These tests can identify increased risk but do not diagnose active disease. Not all genetic causes of HCM are known, and a negative result does not guarantee that a cat will not develop HCM.
Choosing the Right Diagnostic Approach
Diagnostic decisions should be individualized and based on a cat’s age, breed, risk level, clinical signs, and overall health. Echocardiography remains the most definitive tool for diagnosing HCM, while other tests serve supportive or situational roles.
Financial Support
Diagnostic testing can be costly. Cat owners who need help covering the cost of HCM-related diagnostics or treatment are encouraged to contact Ezra’s Heart Foundation to learn more about available financial assistance.
Disclaimer
This information is provided for educational purposes only and is not a substitute for professional veterinary care. Always consult a qualified veterinarian regarding diagnosis and treatment decisions for your feline friends.
References
1. de Sousa FG, Mendes ACR, Carvalho LP, Beier SL. Clinical-Diagnostic and Therapeutic Advances in Feline Hypertrophic Cardiomyopathy. Vet Sci. 2025;12(3):289. Reviewed diagnostic modalities and clinical evaluation of HCM in cats. (https://pmc.ncbi.nlm.nih.gov/articles/PMC11946439/)
2. Payne J, Buchanan J, et al. Echocardiography and ancillary diagnostic tools in feline hypertrophic cardiomyopathy assessment. The Feline Cardiomyopathies chapter. (https://pmc.ncbi.nlm.nih.gov/articles/PMC8642168/)
3. Laudhittirut P, et al. Accuracy of methods for diagnosing heart diseases in cats including NT-proBNP and radiography. PubMed. (https://pubmed.ncbi.nlm.nih.gov/32636581/)
