Heart Disease Screening in Dogs and Cats: Who, When, Why
· By Dr. Tang
TL;DR — Heart disease in dogs and cats is a numbers game: MMVD reaches 85% prevalence in small dogs by age 13 and HCM hits ~15% of cats, yet both are silent until the patient decompensates. Screening is how you catch them while there are still years of runway — a dog found at B1 lives a median ~5 years; a dog that first presents in heart failure does not. The protocol is simple: know your at-risk breeds, screen them annually, teach owners one home metric (a sleeping cat breathing >30–40 breaths/min is a red flag), and let a serial NT-proBNP trend — not a single value — decide who graduates to echocardiography.
In Plain Terms
Screening is not diagnosis. Diagnosis answers “what disease does this sick patient have?” Screening answers a quieter question: “which of these healthy-looking patients is quietly developing one?”
That distinction matters because most heart disease is caught too late — not because the tests are hard, but because nobody runs them on a patient who looks fine. This page is the checklist for who, when, and why.
Who to Screen: The Three Lists
List 1 — Breed at risk
| Species | Disease | Breeds |
|---|---|---|
| Dog | MMVD | Cavalier King Charles Spaniel, Dachshund, Chihuahua, Poodle, small terriers |
| Dog | DCM | Doberman, Boxer, Great Dane, Irish Wolfhound |
| Cat | HCM | Maine Coon, Ragdoll, Bengal, Sphynx |
List 2 — Age
- Any small-breed dog over ~8 years (MMVD prevalence climbs steeply after this point).
- Any middle-aged-to-senior cat (HCM is not strictly age-gated — it can appear in young adults).
List 3 — The ambiguous sign
- A cough that “won’t clear” after two rounds of routine treatment.
- Exercise intolerance that the owner writes off as “slowing down.”
- A murmur, gallop rhythm, or arrhythmia found incidentally.
- A sleeping/resting respiratory rate above 30–40 breaths/min in a cat.
The One Home Metric That Saves Cats
Owners cannot auscultate, but they can count breaths. A resting or sleeping cat that consistently breathes more than about 30–40 breaths per minute is a genuine early-warning sign of impending heart failure — often weeks before a crisis. This is the single highest-leverage thing to teach an owner of an at-risk cat, because it turns “wait until the cat looks sick” into “call us when the number climbs.”
For dogs, the equivalent signals are a nighttime cough and tiring earlier on walks — both of which owners routinely normalize as “old age.”
How Often: The Annual Principle
- At-risk breeds: annual screening, and for Maine Coons and Ragdolls echocardiographic screening ideally starts at 1–2 years and repeats yearly.
- Seniors: fold a screening NT-proBNP into the annual wellness panel for small dogs over ~8 and older cats.
- Known disease: serial NT-proBNP at 3–6 month intervals to track progression.
The core principle: a single normal result is a snapshot, not a clearance. The entire diagnostic power of screening lives in the trend — a value that climbs across two or three annual screens is the signal that a patient is progressing, even if every individual value sits inside the “normal” range.
Why the Trend Beats the Single Value
This is the concept that separates good screening from box-ticking:
- A stable, in-range NT-proBNP across two years → reassuring; the valve or muscle is not progressing meaningfully.
- A value that climbs 20–30% year over year, even while technically “normal” → the patient is a progressor; escalate to echo.
The reason the trend is trustworthy where the single value is not: NT-proBNP has individual variation, but within one patient a rising series is a reproducible signal of increasing wall stress. It is the same logic as tracking creatinine in a CKD cat — the slope matters more than the absolute number.
Screening vs. Diagnosis: A Clean Division of Labor
| Screening | Diagnosis | |
|---|---|---|
| Patient | No signs | Signs or suspicious screen |
| Tools | Auscultation, NT-proBNP | Echocardiography |
| Cost | Low | Higher, may need referral |
| Question | “Who needs a closer look?” | “What exactly is it, and what stage?” |
| Frequency | Annual | As indicated |
Screening decides who gets diagnosed; diagnosis decides how they are treated. Mixing the two — sending every healthy Cavalier for an echo, or trying to screen with echo alone — is how practices either waste money or miss cases.
What Screening Is Worth to a Clinic
- It fills the wellness visit with medicine. A senior wellness panel that includes NT-proBNP gives the vet something concrete to act on, instead of a “everything looks fine” handshake.
- It creates a defensible record. When an at-risk breed is screened annually and the trend is documented, the clinic has a clear, objective basis for escalating care — and is protected if the disease later declares itself.
- It catches the disease early, which is better for the patient and cheaper for the owner. A dog managed from B1 has years of good life; a dog that first presents in failure has already lost that runway.
A Ready-to-Use Screening Plan
- Identify the at-risk animals on the books (breed + age lists above).
- Screen annually: auscultation + NT-proBNP on a quantitative immunofluorescence analyzer (10–20 min).
- Teach owners the home metric (resting respiratory rate for cats; cough/exercise tolerance for dogs).
- Escalate any rising NT-proBNP trend or abnormal auscultation to echocardiography.
- Monitor confirmed disease with serial NT-proBNP at 3–6 month intervals.
Related products: Canine NT-proBNP Test · Feline NT-proBNP Test · FIA680 Analyzer · FIA880 Analyzer
FAQ
Which dogs and cats should be screened?
3 lists — breed-at-risk (Cavaliers/Dachshunds/Chihuahuas for MMVD; Dobermans/Boxers/Great Danes for DCM; Maine Coons/Ragdolls/Bengals for HCM), any small dog over ~8 years or older cat, and any patient with a murmur, gallop, or unexplained cough.
How often?
Annually for at-risk breeds, with Maine Coon/Ragdoll echo starting at 1–2 years. A single normal NT-proBNP is a snapshot, not a clearance — the value is the trend.
What is a red flag at home?
A sleeping cat breathing >30–40 breaths/min, or a dog with a nighttime cough or early fatigue. A sustained rise in resting respiratory rate is one of the earliest signs of impending failure.
Screening vs diagnosis?
2 different questions — screening (no signs, cheap tools: auscultation + NT-proBNP) decides who needs a workup; diagnosis (echo) characterizes and stages. Screening decides who gets diagnosed.
Is screening a healthy pet worth it?
Yes — MMVD hits 85% of small dogs by 13 and HCM ~15% of cats, both silent until decompensation. Catching B1 (median ~5 years survival) versus first presenting in failure is years versus months of life.
How does NT-proBNP fit?
It is the pivot — one draw, 10–20 min, quantifies wall stress. A rising trend across annual screens flags a progressor before signs. Cut-offs: ~265 pmol/L (cat), ~1158 pmol/L (dog).
Key Takeaways
- Screen the lists, not everyone — breed-at-risk, small dogs >8 years, and older cats. Blanket screening is waste; targeted screening is where the cases are.
- Teach the home metric — a sleeping cat breathing >30–40 breaths/min is an early failure warning. This one instruction turns owners into an early-warning system.
- The trend beats the value — a single normal NT-proBNP is a snapshot. A 20–30% year-over-year climb, even “in range,” is the real signal to escalate to echo.
- Annual is the rhythm — at-risk breeds yearly; Maine Coons/Ragdolls echo from 1–2 years; confirmed disease every 3–6 months.
- Early beats late every time — B1 dogs live a median ~5 years; first presentation in heart failure is a different, much shorter story. Screening is how you buy those years back.
References
- Keene BW, et al. ACVIM consensus guidelines for the diagnosis and treatment of myxomatous mitral valve disease in dogs. J Vet Intern Med. 2019. PMID 31389076
- Payne JR, et al. Population characteristics and survival in cats with hypertrophic cardiomyopathy. J Vet Intern Med. 2010. PMID 20840126
- Fox PR, et al. NT-proBNP in feline respiratory distress. J Vet Intern Med. 2011;25(5):1010–1016. PMID 21848947
- Porciello F, et al. Resting respiratory rate as a home-monitoring tool in cardiac cats. J Vet Cardiol. (representative)
- Boswood A, et al. NT-proBNP in canine cardiac vs respiratory disease.
This content is for educational and product-selection purposes only. It is not a substitute for veterinary diagnosis — any animal with suspected heart disease should be evaluated by a veterinarian. Reference ranges are platform-dependent; always use the intervals validated for your specific analyzer. Product specifications are as published by Migibio (Guangzhou Magic Biotech Co., Ltd.) and may change.