Breed Health Guide • Reviewed by Dr. Tiffany Delacruz, DVM
Hypertrophic Cardiomyopathy (HCM) in Devon Rexes
Also known as: HCM
Devon Rex cats have documented elevated risk for Hypertrophic Cardiomyopathy. The breed also has its own characteristic muscle and skin issues, but HCM is the most clinically important cardiac concern. Annual cardiac screening starting young is the standard recommendation.
Why Devon Rexes are predisposed to hypertrophic cardiomyopathy (hcm)
Genetic. Devon Rex appears in HCM breed-risk literature alongside Maine Coons, Ragdolls, British Shorthairs, Norwegian Forest Cats, and Sphynx. The exact mutations in Devon Rex are less well-characterized than in Maine Coons (MYBPC3) and Ragdolls (different MYBPC3 mutation), but breed-clustering of cases is documented.
What you'll see at home
- Often NONE in the early disease phase
- Increased resting respiratory rate (>30 in a sleeping cat is concerning)
- Open-mouth breathing at rest
- Lethargy
- Heart murmur or gallop on exam
- Sudden hind limb paralysis — saddle thrombus, EMERGENCY
- Sudden death in some cases
Red flags — go to an emergency vet
- ⚠ Sudden hind limb paralysis with screaming — saddle thrombus, drive to ER
- ⚠ Open-mouth breathing at rest
- ⚠ Severe respiratory distress
- ⚠ Collapse
How vets diagnose hypertrophic cardiomyopathy (hcm)
Annual cardiac auscultation. Echocardiogram is the gold standard. NT-proBNP screening blood test can help identify cats needing echocardiogram.
Treatment options
Similar to other HCM cats: monitoring for mild cases; atenolol or clopidogrel based on disease stage; furosemide plus ACE inhibitor for CHF; clopidogrel for thromboembolism prevention in severely enlarged left atrium. Lifelong cardiology follow-up.
Living with a Devon Rex who has hypertrophic cardiomyopathy (hcm)
- 1 Annual cardiac auscultation from young adulthood
- 2 Echocardiogram if any murmur, gallop, or unexplained tachycardia is found
- 3 Count resting respiratory rate at home
- 4 Clopidogrel for prevention of saddle thrombus in cats with significant atrial enlargement
- 5 Lifelong cardiology follow-up for confirmed HCM
- 6 Be careful with IV fluid administration during any procedure
- 7 Pet insurance for cardiac conditions is meaningful
Can RexVet help with this online?
RexVet is well-suited for: refilling cardiac medications, coaching on home respiratory rate monitoring, explaining echocardiogram results, and quality-of-life conversations.
Start a $64.99 video visit →We cannot perform cardiac diagnostics by video. Initial diagnosis and ongoing cardiology care belong with a veterinary cardiologist. Saddle thrombus is a true emergency.
Prognosis — what to expect
Variable. Mild HCM may not significantly affect life span. Moderate to severe HCM carries risk of CHF and thromboembolism. Median survival once symptomatic is typically 1-2 years with treatment.
Frequently asked questions
Frequently asked questions
When should my Devon Rex be screened for HCM?
Annual cardiac auscultation from young adulthood. An echocardiogram is reasonable at age 1-2 even without a murmur, then repeat as your cardiologist recommends. Many cats with early HCM have no murmur.
Is HCM the only health concern in Devon Rex?
No — the breed also has hereditary myopathy (a separate muscle disease causing weakness in some lines), patellar luxation in some cats, and skin conditions related to their unusual coat. HCM is the most clinically important cardiac issue, but a comprehensive breed-aware health plan addresses each.
How do I find a vet cardiologist for my Devon Rex?
The American College of Veterinary Internal Medicine maintains a cardiology specialty directory at acvim.org. Most major metro areas have at least one veterinary cardiology specialist. Your primary vet can refer if a screening echocardiogram identifies HCM.
Further reading from the RexVet blog
Other helpful RexVet resources for Devon Rexes parents
Sources
Last fact-checked: 2026-06-04. Reviewed by Dr. Tiffany Delacruz, DVM.
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