Newfoundland and subaortic stenosis: what 14 years of French screening changed
Subaortic stenosis is the signature heart condition of the Newfoundland, to the point where it has become a reason for suspicion among buyers. A recent French publication finally lets us put an up-to-date figure on that risk — and it is far lower than expected. Our piece on Newfoundland health: heart, stones and hips covers the breed's watch points; this one focuses on the heart and on screening.
What the condition is
It is a fibrous narrowing sitting just below the aortic valve, forcing the left ventricle to work against an obstacle. On auscultation it produces a systolic murmur heard at the left heart base. Mild forms go unnoticed for life; severe ones bring exercise intolerance, fainting, endocarditis and sudden death in young adults.
An inherited condition proven back in 1976
The hereditary nature is not guesswork: breeding experiments by G. Pyle, D. Patterson and C. Chacko, published in 1976 in the American Heart Journal, established that discrete subaortic stenosis in the Newfoundland is an inherited trait (study on Google Scholar). That work also describes the full severity spectrum, from a subclinical forme fruste to a form fatal before maturity, with foci of necrosis and fibrosis in the left ventricular myocardium in the worst-affected dogs.
What the French screening programme found
This is the new data. The study by V. Chetboul, C. Fauveau, P. Passavin and colleagues, published in 2025 in PLOS ONE, reports fourteen years of a French cardiovascular screening programme for the breed: 921 dogs examined between 2010 and 2023, median age 1.9 years, with clinical examination, full M-mode, two-dimensional and Doppler echocardiography and an ECG, all reviewed by a board-certified cardiologist (study on Google Scholar). Aortic stenosis prevalence came out at 0.9%, pulmonic stenosis at 0.2%. More striking still: no case of either was detected during the last three years of the programme, the most recent aortic stenosis case dating from 2019. In Newfoundlands from screened French lines, subaortic stenosis is now rare.
What that changes when buying a puppy
The good news is conditional: it describes a screened population. So ask the breeder for both parents' dated cardiac screening certificates, specifying Doppler echocardiography and not just auscultation — a faint murmur can escape the ear, and conversely many puppies have an innocent physiological murmur that fades. A murmur in a puppy therefore does not mean disease: it means an echocardiogram is needed, not panic. The rest of the breed's profile is on the Newfoundland breed profile and in our dog care and grooming section.
On the budget side
Follow-up echocardiograms, cardiology consultations and a possible lifelong beta-blocker make a lasting expense line — and a heart condition already diagnosed is never covered afterwards. In a giant breed where every procedure is billed by size, signing up before the first abnormal examination makes all the difference: see insuring a Newfoundland.
Frequently asked questions
Does a Newfoundland with a murmur need surgery?
Surgery is only considered in rare severe forms. Management rests mainly on echocardiographic follow-up and, if needed, medical treatment.
At what age should screening be done?
Breeding examinations are performed in young adults, generally from twelve months, when the lesion is established and physiological murmurs have gone.
Can an affected dog live normally?
Mild forms allow a normal life with an annual check. Moderate to severe forms mean limiting intense exercise.
This guide is part of Planète Pets’s Dogs universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.