I need to be honest about something. Writing about Cavalier King Charles Spaniels and heart disease isn’t a fun topic. But it’s one of the most important things any current or prospective Cavalier owner needs to understand — because this isn’t a “might happen” situation. It’s a “when” situation.
A close friend of mine has had Cavaliers for over a decade. I’ve watched her navigate vet appointments, medications, and the emotional weight of knowing her dogs carry a genetic time bomb. She’s also one of the most informed dog owners I know, and her experience has shaped a lot of what I’m sharing here.
If you’re considering bringing a Cavalier into your life, or you already have one curled up next to you on the couch, this guide covers everything from the science behind their heart problems to practical steps you can take right now.
Why Heart Disease Defines This Breed
I don’t say this to be dramatic. Heart disease doesn’t just affect Cavalier King Charles Spaniels — it defines the breed’s health profile in a way that no other condition defines any other breed. That’s not an exaggeration.
Mitral Valve Disease (MVD) Prevalence in Cavaliers
Here’s the number that stops people in their tracks: nearly 100% of Cavalier King Charles Spaniels will develop mitral valve disease by age 10. Around 50% already have it by age 5. No other breed comes close to these numbers.
For context, MVD affects plenty of small breeds as they age — Dachshunds, Miniature Poodles, Chihuahuas. But in those breeds, it typically shows up in senior dogs, around 10-12 years old. Cavaliers develop it years earlier, progress faster, and are far more likely to die from it. The Cavalier Health Foundation has been tracking this for decades, and the data is consistent and sobering.
The cavalier king charles spaniel heart problems aren’t a recent discovery either. Researchers identified the breed’s predisposition back in the 1980s, and despite decades of awareness, the prevalence hasn’t meaningfully declined. That tells you something about how deeply embedded this is in the breed’s genetics.
Syringomyelia — The Other Major Concern
I want to briefly mention syringomyelia (SM) because it’s the other major health issue in this breed, and it sometimes overlaps with heart disease management. SM is a condition where the skull is too small for the brain, forcing cerebrospinal fluid into the spinal cord. It causes pain, scratching at the air, and neurological symptoms.
Why mention it here? Because when you’re managing a Cavalier’s health, you’re often juggling multiple conditions simultaneously. A dog on heart medications may also need pain management for SM. It complicates things. And it’s another reason why choosing your breeder carefully matters so much — but we’ll get to that.
Understanding Mitral Valve Disease
What Happens Inside the Heart
The mitral valve sits between the left atrium and left ventricle. Think of it as a one-way door. Blood flows through from the atrium to the ventricle, the valve snaps shut, and the ventricle pumps blood out to the body.
In MVD, the valve’s leaflets thicken and degenerate over time. They stop closing properly. Blood leaks backward — that’s called regurgitation — and you get a heart murmur. That whooshing sound your vet hears? It’s blood going the wrong direction.
At first, the heart compensates. It works harder. The chambers enlarge to handle the extra volume. Your dog seems perfectly fine. But the heart can only compensate for so long. Eventually, the left atrium stretches so much that the heart can’t keep up, fluid backs into the lungs, and you’re looking at congestive heart failure.
The scary part is how long your dog can seem completely normal. My friend’s Cavalier, Biscuit, had a Grade 3 murmur for almost two years before showing any outward symptoms. He was running around the yard, eating well, being his usual velcro-dog self. Inside, his heart was slowly losing the battle.
Stages of MVD (ACVIM Stages A Through D)
The American College of Veterinary Internal Medicine (ACVIM) created a staging system that every Cavalier owner should understand. It guides treatment decisions and gives you a framework for what’s happening.
| Stage | What It Means | What You’ll Notice | Typical Action |
|---|---|---|---|
| A | At risk, no murmur detected | Nothing — dog is clinically normal | Annual heart checks |
| B1 | Murmur present, no heart enlargement | Nothing visible — detected by vet only | Monitor every 6-12 months |
| B2 | Murmur with confirmed heart enlargement | Usually still no symptoms | Start pimobendan — this is the critical window |
| C | Congestive heart failure (current or past) | Coughing, labored breathing, fatigue, reduced appetite | Multiple medications, activity restriction |
| D | End-stage, refractory to treatment | Severe symptoms despite maximum medication | Palliative care, consider surgical referral |
The jump from B1 to B2 is the one that matters most for treatment. And the only way to tell the difference? An echocardiogram. A stethoscope alone can’t determine heart size.
Early Detection and Screening
When to Start Heart Checks
Don’t wait until your Cavalier is middle-aged. Start annual cardiac exams at age 1. Yes, one year old.
I know that sounds aggressive for a puppy that’s bouncing off the walls. But cavalier spaniel mitral valve disease can develop early, and catching it sooner gives you more options. Some cardiologists even recommend a baseline echocardiogram at 1-2 years old, so you have a comparison point for later scans.
After age 5, bump it to every 6 months if your vet or cardiologist recommends it. Once a murmur is detected, frequency should increase based on your cardiologist’s guidance.
Echocardiogram vs Stethoscope Exam
This is where I get a little frustrated with general practice veterinary care. A regular vet check where they listen with a stethoscope is a good starting point. It can detect a murmur and roughly grade its severity (1-6 scale). But it cannot tell you:
- Whether the heart chambers have enlarged
- The direction and severity of blood regurgitation
- Whether your dog has crossed from B1 to B2
- How well the heart muscle is actually functioning
An echocardiogram can. It’s an ultrasound of the heart, ideally performed by a board-certified veterinary cardiologist. It measures chamber sizes, valve function, and blood flow in real time.
The cost difference matters — a stethoscope exam is part of a regular checkup, while an echocardiogram runs $300-$600 depending on your location. But for Cavaliers specifically, echocardiograms aren’t optional. They’re the difference between catching the disease at B2 (when medication can buy 15+ months) and missing it until your dog is in heart failure.
The MVD Breeding Protocol Explained
The MVD breeding protocol is the best tool we have for reducing heart disease in the breed. It’s straightforward:
- Both parents must have clear cardiac exams at age 5 or older
- All four grandparents should ideally have been clear at age 5+
- Clearances must come from a board-certified cardiologist (not a general practice vet)
- Dogs with early-onset murmurs should be removed from breeding programs entirely
That’s it. Simple in theory. Hard in practice — because it means waiting until dogs are 5 before breeding them, which requires patience and financial commitment from breeders.
Does it work? The research says yes. Dogs from parents who were clear at older ages develop MVD significantly later than dogs from unscreened parents. It won’t eliminate the disease, but it can push the onset from age 4-5 to age 8-10. That’s a huge difference in quality of life.
Symptoms to Watch For at Each Stage
The tricky thing about CKCS heart murmur progression is how silent the early stages are. Here’s what to watch for as the disease advances:
Stages A and B1 — Honestly, nothing. Your dog will act completely normal. This is why screening matters so much. You cannot detect these stages at home.
Stage B2 — Still often asymptomatic, but some owners notice:
– Slightly reduced stamina on long walks
– Occasional restlessness at night
– A subtle increase in breathing rate during sleep (count the breaths — more than 30 per minute while sleeping is a red flag)
Stage C — This is when most owners first realize something is wrong:
– Persistent cough, especially at night or after excitement
– Heavy or rapid breathing
– Reluctance to exercise or play
– Loss of appetite or weight loss
– Fainting episodes (syncope)
– Swollen belly from fluid retention
Stage D — Everything above, but worse and not responding well to medications. Breathing difficulties become constant. Quality of life deteriorates significantly.
One practical tip: learn to count your dog’s sleeping respiratory rate. When they’re resting peacefully, count chest movements for 30 seconds and multiply by two. Write it down weekly. A normal sleeping rate is under 30 breaths per minute. A consistent increase above that — even before you notice coughing — is often the first measurable sign of trouble. There are even smartphone apps designed for this (Cardalis is one).
Treatment Options and Management
Medications That Extend Life
The landmark EPIC trial changed everything for Cavalier heart health screening and treatment. Published in 2016, it showed that pimobendan (Vetmedin) delays the onset of heart failure by a median of 15 months when started at Stage B2.
Fifteen months. For a breed with a median lifespan of 9-14 years, that’s significant. It’s the single most impactful medical intervention available.
Here’s the typical medication progression:
Stage B2:
– Pimobendan (Vetmedin) — the game-changer. Strengthens heart contractions and opens blood vessels.
Stage C:
– Pimobendan continues
– Furosemide (Lasix) — a diuretic that pulls fluid from the lungs
– An ACE inhibitor (enalapril or benazepril) — reduces strain on the heart
– Spironolactone — another diuretic that works differently, often added for additional benefit
Stage D:
– Higher doses of the above
– Additional diuretics (torsemide may replace furosemide)
– Possibly sildenafil for pulmonary hypertension
– Anti-arrhythmics if heart rhythm problems develop
The medication costs add up. My friend spends about $150-200 per month on Biscuit’s heart medications at Stage C. That’s before regular cardiology visits. It’s not cheap, but pimobendan is available as a generic now, which helps.
Diet and Exercise Modifications
This is an area where you’ll find conflicting advice. Here’s what the current evidence supports:
Diet: Sodium restriction was once standard advice for all heart disease dogs. Current thinking is more nuanced. Mild sodium restriction makes sense at Stage C and beyond, but severe restriction isn’t recommended and can actually be counterproductive. Your dog still needs a complete, balanced diet. Don’t go buying “cardiac” dog food without consulting your cardiologist.
Omega-3 fatty acids (fish oil) may help reduce inflammation. Some cardiologists recommend them. The doses are higher than what’s in standard dog food — ask your vet about therapeutic dosing.
Exercise: This depends entirely on the stage.
– Stages A through B2: Normal activity. Let your dog be a dog. Regular walks, play sessions, all good.
– Stage C: Moderate activity is usually fine and even beneficial, but avoid intense exercise. No long runs or rough play sessions that leave your dog panting hard. Short, gentle walks. Let your dog set the pace.
– Stage D: Very limited activity. Short bathroom walks. Keep your dog comfortable.
Weight management is arguably the most important lifestyle factor. An overweight Cavalier’s heart is working harder than it needs to. Keep your dog lean. I know those puppy eyes are hard to resist, but carrying extra weight accelerates heart disease progression.
When Surgery Becomes an Option
Mitral valve repair surgery exists, and for the right candidate, the results are remarkable. A handful of specialized centers — notably in Japan, France, the UK, and a few locations in the US — perform open-heart surgery to repair the damaged valve.
The numbers: success rates above 90% in experienced centers, with many dogs returning to essentially normal heart function. Dogs that were in Stage C, on multiple medications, running around like puppies again.
The catch: it costs $20,000 to $40,000. The waiting lists can be long. Not every dog is a candidate — the surgery works best for dogs in early-to-mid Stage C who are otherwise healthy. And there are real surgical risks, including a small percentage that don’t survive the procedure.
Is it worth it? For some families, absolutely. I’ve seen owners fundraise, take out loans, and drive across the country for this surgery. When it works — and it usually does — it can give a dog years of healthy, medication-free life. But it’s not realistic for everyone, and there’s no shame in managing the disease medically.
Choosing a Breeder Who Tests for MVD
If you haven’t bought your Cavalier yet, this section might be the most important one in this entire guide.
Questions to Ask About Heart Clearances
Here’s exactly what to ask any breeder, and the answers you should hear:
-
“Have both parents had cardiac clearances by a board-certified cardiologist?” — The answer should be yes, with documentation you can verify. OFA (Orthopedic Foundation for Animals) records are searchable online.
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“At what ages were the parents cleared?” — You want to hear age 5 or older. A clearance at age 2 means almost nothing for MVD screening. The whole point is proving the dog hasn’t developed early-onset disease.
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“What’s the heart history of the grandparents?” — A great breeder knows this. They should be able to tell you the grandparents’ cardiac status and ages at last clearance.
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“Have any offspring from previous litters developed early murmurs?” — An honest breeder will tell you. Every breeding program has some affected dogs. Transparency matters more than perfection.
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“Do you follow the MVD breeding protocol?” — If they don’t know what this is, walk away.
Red flags to watch for:
– “My vet said the hearts are fine” — Not the same as a cardiologist clearance
– Breeding dogs under age 3 with no older relatives tested
– Inability to provide OFA numbers or cardiology reports
– Getting defensive about health questions
– “None of my puppies have ever had problems” — Statistically impossible in this breed if they’ve been breeding for any length of time
I’ll be blunt: a well-bred Cavalier from health-tested parents will cost $2,500-$4,000+. A puppy from a breeder who cuts corners on health testing will cost less upfront and potentially tens of thousands more in veterinary bills. The cavalier king charles spaniel heart problems in this breed are serious enough that genetic screening isn’t optional — it’s the minimum standard.
Living with a Cavalier with Heart Disease
Here’s what my friend would want you to know after years of managing Biscuit’s MVD:
It’s not a death sentence. Many Cavaliers live good, happy lives for years after a murmur diagnosis. The disease is manageable. It requires vigilance, yes, and medication, and regular vet visits. But your dog doesn’t know they have heart disease. They still want belly rubs and to follow you from room to room and steal your spot on the couch the second you stand up.
Build a relationship with a veterinary cardiologist. Don’t rely solely on your general practice vet for cardiac care. A cardiologist will catch changes earlier, adjust medications more precisely, and give you a clearer picture of where your dog stands.
Track the sleeping respiratory rate. I mentioned this earlier, but it’s the single best at-home monitoring tool. Do it consistently. Write it down or use an app. A rising trend is your earliest warning sign that something is changing.
Plan financially. Between cardiologist visits ($300-600 each), echocardiograms, medications ($100-200/month), and potential emergencies, cavalier heart health screening and treatment adds up. Pet insurance purchased before any diagnosis can help enormously — but read the fine print on pre-existing condition exclusions.
Give yourself grace. Loving a breed with a known health issue is emotional. You’ll second-guess decisions, worry about every cough, and feel guilty about things beyond your control. That’s normal. Join a Cavalier health community — the Cavalier Health website and breed-specific Facebook groups have thousands of owners navigating the same path.
And despite all of it? Every single Cavalier owner I know says they’d do it again. There’s something about this breed — their gentleness, their devotion, the way they tuck themselves into the crook of your arm — that makes people come back. Just go in with your eyes open.
Frequently Asked Questions
At what age should I start screening my Cavalier for heart disease?
Start at age 1 with annual cardiac exams by your regular vet. Get a baseline echocardiogram by a board-certified cardiologist between ages 1-2. After age 5, or anytime a murmur is detected, increase to every 6 months. Early detection directly impacts treatment options and outcomes.
Can cavalier king charles spaniel heart problems be prevented?
Not entirely — the genetic predisposition is deeply embedded in the breed. However, buying from breeders who follow the MVD breeding protocol (both parents cardiac-clear at 5+) significantly delays onset. Once your dog has the disease, keeping them at a healthy weight and starting pimobendan at Stage B2 are the best ways to slow progression.
How long can a Cavalier live with a heart murmur?
It depends heavily on the stage at diagnosis and how well the disease is managed. A dog diagnosed with a mild murmur at B1 may live 3-5+ years before progressing to heart failure — sometimes longer. With treatment at Stage C, many dogs live 1-3 additional years with good quality of life. The EPIC trial showed pimobendan adds roughly 15 months before the onset of heart failure when started at B2.
How much does it cost to manage heart disease in a Cavalier?
Budget for $300-600 per cardiologist visit (usually 2-4 times per year), $100-200 per month in medications at Stage C, plus potential emergency visits ($1,000-3,000+). If considering mitral valve repair surgery, that’s $20,000-$40,000. Pet insurance purchased before any diagnosis can offset many of these costs.
Is mitral valve repair surgery worth it for my Cavalier?
For the right candidate — a Stage C dog at an experienced surgical center — success rates exceed 90%, and many dogs return to normal heart function without daily medications. The cost ($20K-40K) and limited availability are the main barriers. Discuss candidacy with your cardiologist; not every dog is a good surgical candidate, and medical management remains effective for most.
Should I get a Cavalier knowing about these heart issues?
That’s a deeply personal decision. The breed’s temperament is extraordinary — they’re among the most loving, gentle companions you’ll find. But you need to go in informed. Choose a breeder who health-tests rigorously, set aside a veterinary fund, and commit to regular cardiac screening. If you can do those things, most Cavalier owners will tell you the love is absolutely worth it.
Heart disease in Cavalier King Charles Spaniels isn’t going away anytime soon. The genetics are too entrenched, and the breed’s popularity means plenty of breeders still aren’t following best practices. But the tools for managing it — early screening, pimobendan, improved surgical techniques — are better than they’ve ever been. Your Cavalier deserves an owner who understands what they’re facing and is prepared to act on it. That you’re reading this guide tells me your dog is in good hands.
Featured Image Source: Pexels
