Overview

PS is congenital narrowing at the pulmonary valve in the right ventricular outflow tract. Abnormal valve formation is most common, though narrowing can also occur below or above the valve.

The right ventricle must generate greater pressure to pump through the narrowed passage. Its wall gradually thickens. Greater narrowing creates more load and can eventually cause right-sided heart failure, ascites or exercise-related fainting.

Many mild cases remain largely symptom-free throughout life. Accurately identifying mild, moderate or severe narrowing on imaging is the starting point for management.

Predisposed breeds

PS is reported more frequently in:

English Bulldog, French Bulldog and Boston Terrier
Beagle and Miniature Schnauzer
West Highland White Terrier and Cocker Spaniel
Chihuahua, Samoyed and Mastiff breeds

Even outside these breeds, a systolic murmur over the upper left chest in a puppy warrants assessment for congenital disease, including PS.

What signs should I watch for?

Mild PS may be found only on auscultation without an activity change. Severe disease or concurrent conditions may cause:

A relatively loud systolic murmur over the upper left chest, often first detected in a puppy examination
Slow recovery and prolonged panting after gentle walks or stairs compared with peers
Sudden fainting during excitement or exercise, especially concerning in severe disease
Repeated increases above the usual sleeping respiratory rate
Abdominal swelling from ascites or reduced appetite with advanced right-sided heart failure
Pale or bluish gums

Severe PS can cause exercise-related fainting in young dogs

Even an otherwise active puppy with only a murmur can briefly lose consciousness during a walk or excitement. Do not dismiss a single episode; imaging to establish severity is safer.

Diagnostic steps

Diagnosis centers on objectively measuring the severity of narrowing, using the following information.

Auscultation

Assess murmur intensity and location over the upper left chest. A loud murmur may suggest significant narrowing, but loudness alone does not determine severity.
Chest X-rays

Assess right ventricular enlargement, post-stenotic pulmonary artery dilation and changes associated with advanced right-sided heart failure.
Echocardiography

Identify the location and form of narrowing and measure the pressure gradient with Doppler. This core test grades severity and informs intervention eligibility.
ECG

Assess right ventricular enlargement patterns and arrhythmias. Rhythm assessment is especially important after fainting.
Blood tests + NT-proBNP

Assess kidney and liver function and electrolytes. NT-proBNP can support assessment of right ventricular strain and provide pre-anesthetic baseline information.

Severity grading

PS is generally classified as mild, moderate or severe using the Doppler pressure gradient. Recommended care varies by grade.

Severity	Condition	Management approach
Mild	Low gradient and mild right ventricular thickening; activity often resembles that of peers	Usually annual imaging and activity observation without intervention
Moderate	Intermediate gradient and clear ventricular thickening; slow exercise recovery may occur	Follow-up every 6–12 months according to symptoms and imaging, with assessment of intervention eligibility
Severe	High gradient and marked ventricular thickening, with increased fainting and right-sided heart failure risk	Assess balloon valvuloplasty eligibility and refer, alongside medication and daily care

These categories illustrate a general framework. Individual ultrasound and clinical findings determine grading and intervention eligibility.

Treatment and care by stage

The intensity of care varies substantially with severity. Our approach includes:

Severe PS — Referral for intervention

After assessing eligibility, we refer severe PS to a cooperating center offering balloon valvuloplasty. We provide ultrasound follow-up, medication management and pre-anesthetic assessment around the procedure.

Medication when indicated

Severe disease, arrhythmias or right-sided heart failure may require combinations to reduce ventricular load and control rhythm. Kidney function, electrolytes and blood pressure guide dose adjustments.

Exercise intensity and daily care

Activity recommendations depend on severity. Mild cases generally maintain ordinary walks; severe cases should avoid vigorous play, running and stairs. Adjust walks in hot or humid weather.

Home monitoring and follow-up

Record SRR once or twice a week, along with exercise recovery time and any fainting or unsteadiness. Imaging is repeated every 6–12 months or sooner depending on severity.

Frequently asked questions

Does a loud murmur mean severe narrowing?

Not always. Murmur intensity is a starting clue, while Doppler pressure gradients and clinical findings establish severity.

Do you perform the procedure at your clinic?

We offer outpatient care and daytime hospitalization. Balloon valvuloplasty is performed at a cooperating center. We provide imaging, ECG, blood testing and pre-anesthetic assessment, then medication management and imaging follow-up.

Can a dog with mild PS go for walks?

Comfortable ordinary walks are generally recommended. Avoid excessive exercise in heat or humidity and highly exciting play; regular imaging checks for severity changes.

Does severe PS always require an intervention?

Assessment for balloon valvuloplasty is generally recommended because it may reduce ventricular load, fainting and right-sided heart failure risk. The referral center determines eligibility and timing using imaging and clinical status.

Can my puppy be neutered first?

For suspected or confirmed PS, assess severity and right ventricular load before other surgery requiring anesthesia. Findings may guide safer surgical timing or accompanying medication.

My dog fainted once. Is that okay?

Exercise-related fainting in PS should not be dismissed. Arrange ultrasound and ECG promptly rather than waiting for the next routine visit.

References

These external resources explain PS diagnosis, treatment and puppy murmurs. They do not define our services or an individual prescription.

Pulmonary stenosis (PS)