Bull Terrier Health, Heart Screening & Breed Research
Hidden Heart Disease in Bull Terriers: What the Studies Actually Show
Bull Terrier heart disease can be hidden behind a strong body. A dog may look powerful, athletic, muscular, and full of life, while still carrying a murmur, valve abnormality, outflow tract problem, or early cardiac remodeling that is not obvious from the outside.
That is one of the most important lessons from the Bull Terrier cardiac literature. This is not a generic dog-health article. Bull Terriers have appeared in serious veterinary studies focused on heart disease, valve abnormalities, vascular lesions, echocardiographic findings, pathology, and cardiac biomarkers.
The message from the research is not panic. The message is responsibility.
A normal-looking Bull Terrier is not automatically a heart-clear Bull Terrier. A dog without obvious weakness, coughing, collapse, or exercise intolerance may still have a murmur, valve abnormality, outflow tract problem, or early cardiac remodeling.
Bull Terrier heart disease deserves serious screening because studies have reported mitral valve abnormalities, aortic stenosis, murmurs, left-sided cardiac remodeling, vascular and conduction tissue changes, and biomarker findings in the breed. Owners should not rely only on appearance or energy. Murmurs, breeding plans, heavy sport, collapse, coughing, poor recovery, or family history should lead to proper veterinary cardiac assessment, often including echocardiography.
Important health note: This article is educational and breed-specific, but it is not a diagnosis. If your Bull Terrier has a murmur, collapse episode, coughing, exercise intolerance, abnormal breathing, or a family history of heart disease, speak with your veterinarian and ask whether referral to a veterinary cardiologist is appropriate.
Why Bull Terrier Heart Disease Deserves Its Own Case Study
In many dog breeds, heart disease is discussed in broad terms: older dogs get murmurs, small breeds get mitral valve disease, or large breeds get cardiomyopathy. But Bull Terriers deserve a more specific conversation.
The available studies repeatedly point toward a complex cardiac picture in the breed, especially involving mitral valve abnormalities, mitral regurgitation, mitral stenosis or increased transmitral gradient, aortic stenosis, left-sided cardiac remodeling, murmurs that may underestimate the true picture, vascular and conduction tissue changes seen on pathology, and the need for echocardiography rather than relying only on outward appearance.
This matters because Bull Terriers are often judged by strength. Owners see a strong dog and assume the heart must be strong too. But structure, muscle, drive, and heart health are not the same thing.
A Bull Terrier can be strong in the body and still need cardiac investigation.
The 2022 Study: Heart Disease in 101 English Bull Terriers
One of the strongest breed-specific papers is the 2022 study “Epidemiology of heart disease in English Bull Terriers and echocardiographic characteristics of mitral valve abnormalities.”
This study retrospectively included 101 English Bull Terriers to evaluate the prevalence and distribution of heart disease in the breed. The researchers found heart disease in 65% of the English Bull Terriers studied. The two most common findings were mitral valve abnormalities, found in 47%, and aortic stenosis, found in 29%.
The study also compared mitral valve measurements in several groups, including healthy English Bull Terriers, English Bull Terriers with mitral valve abnormalities, and a control group from other breeds. The researchers found that healthy English Bull Terriers had a smaller mitral valve area and mitral annulus diameter compared with dogs of similar body surface area.
The clinical message was clear: the authors suggested that mitral valve area, mitral annulus diameter, and mean transmitral gradient should be included in echocardiographic protocols for English Bull Terriers.
The 2009 Pathology Study: What Necropsy Revealed
Another important Bull Terrier paper is the 2009 study “Cardiac valvular and vascular disease in Bull Terriers.”
This study examined the hearts of 27 Bull Terriers and 6 control dogs. Heart murmurs were heard in 14 of the 27 Bull Terriers, which means 52% had murmurs on auscultation.
But the deeper findings were even more important. At necropsy, 25 of the 27 Bull Terriers, or 93%, had either myxomatous degeneration of the mitral valve or abnormalities of the left ventricular outflow tract.
The study also reported that small-vessel arteriosclerosis in the myocardium and fibrosis of cardiac conduction tissue were common histological findings in Bull Terriers with clinical cardiac disease. Importantly, some of these lesions were also found in dogs without clear clinical evidence of heart disease and in dogs with only mild murmurs or mild structural valvular disease.
That is a major point: the visible clinical picture may not always reveal the full cardiac picture.
A Bull Terrier can look active, muscular, and full of drive while still needing a proper heart check. If a murmur, family history, collapse episode, poor recovery, or breeding decision is involved, move from guessing to veterinary screening.
The 2025 Biomarker Study: What Blood Tests Can and Cannot Tell Us
A 2025 paper looked at cardiac biomarkers in English Bull Terriers: “Cardiac biomarkers N-terminal fragment of the prohormone B-type natriuretic peptide and cardiac troponin I for characterization of the cardiac disease phenotype of the English Bull Terrier.”
This prospective case-control study included 15 healthy Bull Terriers and 50 Bull Terriers with various heart disease presentations. The main disease presentations included mitral valve disease and mitral stenosis. The researchers measured NT-proBNP and cardiac troponin I, two biomarkers commonly used to help assess cardiac load, function, and myocardial injury.
The study found that NT-proBNP and cTnI were useful for assessing the degree of severity in known cardiac disease, especially when cardiac remodeling was present. Both biomarkers could help discriminate Bull Terriers with advanced remodeling from those without advanced remodeling.
But the study also made an important caution: the Bull Terrier cardiac phenotype was not associated with a unique cardiac biomarker profile. Instead, biomarker levels were similar to those reported in other breeds with valvular heart disease.
The correct interpretation is that cardiac biomarkers can support the assessment of known disease severity, but they are not a complete screening replacement for a proper cardiac examination and echocardiogram.
Why Murmurs Matter — But Are Not Enough
Many owners only become concerned when a vet hears a murmur. That is understandable. A murmur is often the first sign that something may be wrong.
But the Bull Terrier studies show why relying only on obvious clinical signs is not enough. A murmur may be mild while the underlying issue is more complex. A dog may have structural changes before the owner notices symptoms. Some dogs may appear normal until the disease is more advanced.
This is especially important in Bull Terriers because they are often active, stoic, and physically expressive dogs. They may continue to play, pull, jump, train, and act full of energy even when something is developing internally.
A strong dog does not always advertise weakness early. That is why responsible owners should not wait for collapse, coughing, exercise intolerance, fainting, or visible distress before taking heart findings seriously.
Mitral Valve Abnormalities in Bull Terriers
The mitral valve sits between the left atrium and left ventricle of the heart. If the valve does not function properly, blood flow can become abnormal.
In Bull Terriers, the studies point repeatedly toward mitral valve involvement. Mitral valve abnormalities may include regurgitation, stenosis, altered valve structure, increased transmitral gradient, or changes that contribute to volume overload and remodeling.
This matters because the left side of the heart is responsible for pumping oxygenated blood to the body. When the mitral valve is abnormal, the heart may compensate for a time, but compensation is not the same as health.
For Bull Terriers, a proper cardiac assessment should not only ask whether there is a murmur. It should also ask what the mitral valve is doing, whether there is regurgitation or stenosis, whether the transmitral gradient is increased, and whether the left atrium or left ventricle is remodeling.
Aortic Stenosis and Outflow Tract Problems
The 2022 study found aortic stenosis in 29% of the English Bull Terriers studied. Aortic stenosis means there is narrowing that affects blood leaving the left ventricle through the aortic outflow tract.
Depending on severity, this can increase the workload on the heart and may carry risk for exercise intolerance, arrhythmias, collapse, or sudden death in serious cases.
The 2009 pathology study also reported abnormalities of the left ventricular outflow tract in Bull Terriers. When different studies point toward left-sided valve and outflow tract issues, the breed conversation should become more careful.
Running fine today does not prove the absence of cardiac risk. Performance is not the same as screening.
Cardiac Remodeling: The Stage Owners Often Cannot See
Cardiac remodeling means the heart has started changing in size, shape, or structure in response to disease or increased workload.
Owners usually cannot see remodeling. A dog may still look fit. The chest may still look strong. The dog may still want to work, play, and train. But inside, the heart may be adapting.
The 2025 biomarker study showed that NT-proBNP and cTnI were more useful when interpreted in relation to remodeling severity. Bull Terriers with increased left atrial and left ventricular volumes had higher biomarker concentrations than healthy dogs or dogs without advanced remodeling.
This gives owners a very important lesson: the question is not only whether the dog has heart disease. The question is whether the disease is already changing the heart.
What Bull Terrier Owners Should Watch For
Heart disease can be silent, but owners should still watch for warning signs.
A murmur may be the first clue, but it should not be the final assessment.
A normally active Bull Terrier who slows down deserves attention.
Coughing after exercise or at rest should be discussed with a veterinarian.
Collapse is a serious sign and should never be dismissed as tiredness.
Difficulty settling after activity or unusually fast breathing at rest may matter.
Related dogs with murmurs, cardiac medication, collapse, or sudden death should influence screening decisions.
No symptoms does not always mean no disease. Some dogs are diagnosed because a murmur is heard during a routine exam. Others are found during breeder screening. Some may show no obvious problem until disease has progressed.
Why This Matters for Breeders
This article is not written to scare owners. It is written because Bull Terrier breeding must be honest.
If a breed has documented heart-risk patterns, then breeders should not rely on appearance, confidence, movement, muscle, or temperament alone. A breeding dog should be evaluated as a whole animal.
That includes temperament, structure, movement, skin, kidneys, hearing, mouth and bite, and heart.
For heart health, serious breeders should consider cardiac screening, veterinary cardiology input when possible, and honest record-keeping across lines. If related dogs show murmurs, mitral valve abnormalities, aortic stenosis, sudden death, exercise collapse, or cardiac medication history, that information should matter.
Why This Matters for Working and Active Bull Terriers
Working and active Bull Terriers are often assumed to be healthy because they perform. But performance is not a diagnostic test.
A dog can have drive and disease at the same time. A Bull Terrier may continue to jump, pull, run, bite, tug, climb, and train while the heart is compensating. The dog’s desire to work may hide early decline because the animal pushes through discomfort or fatigue.
That does not mean active dogs should be treated like fragile dogs. It means active dogs deserve proper checks. The more physical demands we place on a dog, the more responsible we must be about knowing what is happening inside the dog.
What This Study Set Does Not Mean
The studies do not mean every Bull Terrier has heart disease. They do not mean every murmur is catastrophic. They do not mean every Bull Terrier should be removed from breeding because of suspicion. They do not mean owners should panic if a vet hears a mild murmur.
They also do not mean blood biomarkers can diagnose everything, or that internet advice can replace veterinary cardiology.
The correct message is more balanced: Bull Terriers have enough breed-specific cardiac evidence that heart screening should be taken seriously, especially in breeding dogs, symptomatic dogs, dogs with murmurs, and active dogs expected to perform physically.
Practical Takeaways for Bull Terrier Owners
If you own a Bull Terrier, the most useful steps are simple.
- Ask your vet to listen carefully for murmurs during routine exams.
- Do not ignore even a mild murmur.
- Consider echocardiography, especially if the dog is used for breeding, heavy sport, or intense training.
- Watch resting breathing rate and recovery after exercise.
- Keep records of murmur grade, echo result, medication, collapse episodes, or family history.
- Do not use normal energy as proof that the heart is normal.
- If biomarkers are used, understand that they support assessment but do not replace imaging.
- For breeding decisions, think in families and patterns, not only individual dogs.
The serious Bull Terrier owner does not separate strength from screening. Heart checks, honest records, veterinary advice, and responsible breeding decisions protect the dog in front of us and the future of the breed.
The WBT Interpretation: The Strong Dog Still Needs Screening
At Working Bull Terriers, we love strength. We respect strong dogs, functional dogs, driven dogs, athletic dogs, and dogs that can actually use their body.
But real strength is not just what we see from the outside. A Bull Terrier is not only muscle, head, bone, grip, and attitude. The heart matters.
The studies show that Bull Terrier cardiac disease can be present in serious numbers within studied groups, that murmurs may not tell the whole story, that valve and outflow tract abnormalities deserve attention, and that modern tools like echocardiography and biomarkers can help us understand severity.
A responsible Bull Terrier owner does not look at a strong dog and say, “He looks fine, so he must be fine.”
A responsible owner says, “He looks strong. Now let’s make sure the inside supports the outside.”
That is the standard the breed deserves.
References and Study Links
- Chompoosan C, Schrøder AS, Höllmer M, Bach MBT, Møgelvang R, Willesen JL, Langhorn R, Koch J. Epidemiology of heart disease in English Bull Terriers and echocardiographic characteristics of mitral valve abnormalities. Journal of Small Animal Practice. 2022;63(5):372–380. doi: 10.1111/jsap.13472. PubMed
- O’Leary CA, Wilkie I. Cardiac valvular and vascular disease in Bull Terriers. Veterinary Pathology. 2009;46(6):1149–1155. doi: 10.1354/vp.06-VP-0230-O-FL. PubMed
- Chompoosan C, Koch J, Schrøder AS, Bach MBT, Willesen JL, Langhorn R. Cardiac biomarkers N-terminal fragment of the prohormone B-type natriuretic peptide and cardiac troponin I for characterization of the cardiac disease phenotype of the English Bull Terrier. Research in Veterinary Science. 2025;191:105686. doi: 10.1016/j.rvsc.2025.105686. PubMed
- Additional PubMed link provided for cardiac research review: PubMed
- Additional PubMed link provided for cardiac research review: PubMed
- Additional PubMed link provided for cardiac research review: PubMed
Frequently Asked Questions About Bull Terrier Heart Disease
Yes. A Bull Terrier can look strong, active, and muscular while still having a murmur, valve abnormality, outflow tract problem, or early cardiac remodeling. Appearance and energy do not replace screening.
Studies have reported mitral valve abnormalities, mitral regurgitation, mitral stenosis or increased transmitral gradient, aortic stenosis, left-sided remodeling, murmurs, and vascular or conduction tissue changes.
No. A murmur check is useful, but it does not show the full internal picture. Echocardiography can evaluate valve structure, blood flow, chamber size, remodeling, and outflow tract abnormalities.
Serious breeders should consider cardiac screening and veterinary cardiology input when possible, especially when there are murmurs, family history, sudden death, exercise collapse, or known valve disease in related dogs.
No. Biomarkers such as NT-proBNP and cardiac troponin I can support assessment of known disease severity, especially when remodeling is present, but they do not replace proper cardiac examination and echocardiography.
Watch for a murmur, reduced stamina, coughing, collapse, fainting, poor recovery after activity, fast breathing at rest, blue or pale gums, sudden slowing down, or family history of heart disease. No symptoms does not always mean no disease.