Can a ventricular septal defect heal on its own?

Small defects may sometimes shrink or close on their own during early life, but most need follow-up echocardiography for assessment. Schedule regular monitoring as recommended by your vet.

Will a ventricular septal defect affect my pet's lifespan?

The impact depends on the size of the defect and whether it causes heart failure or lung complications. Mild cases may remain stable long term, while more serious cases need specialist assessment and regular follow-up.

What tests are needed to confirm the diagnosis?

Common tests include chest X-rays, echocardiography and blood tests; CT or specialist assessment may be arranged depending on the situation. Ask your vet which tests are appropriate.

What treatment options are available?

Treatment depends on the condition and may include medication, interventional closure or surgical repair. A vet or veterinary cardiologist should assess the most suitable plan, with follow-up as directed.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Ventricular Septal Defect in Dogs and Cats: Rapid Breathing, Heart Murmurs, Tests & Care [2025]

A congenital heart disease where there is a defect between the left and right ventricles; small defects may be monitored, while large defects can lead to heart failure

Take 1 minute to check the symptoms first

Last updated: 2026/01/06

Pethealthmap Editorial Team

Sources: ACVIM, AAHA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek immediate veterinary care (emergency)

•Persistent open-mouth breathing or obvious labored breathing with no clear improvement
•Repeated fainting or brief loss of consciousness with difficulty waking
•Purple gums or lips, pale coloration, and rapid breathing

Schedule a veterinary visit as soon as possible (within 24-72 hours)

•Marked rapid breathing or reduced stamina after exercise or excitement
•Persistent or recurrent coughing that affects rest or eating
•Reduced activity tolerance, easy fatigue, or lethargy

01What symptoms suggest something is wrong?

A ventricular septal defect often increases strain on the heart and lungs and changes blood flow. Dogs and cats may show changes in breathing, heart function and general activity, and some cases have emergency warning signs that need immediate veterinary care.

Persistent or intermittent coughing, panting, or faster breathing
Noticeable shortness of breath and reduced stamina after exercise or excitement
Activity changes linked to a fast heartbeat or irregular heart rhythm
Regurgitating milk, difficulty swallowing, or occasional food reflux
Sudden fainting or brief episodes of loss of consciousness
A heart murmur or abnormal heart sounds may be found on auscultation

Seek emergency care immediately if you notice the following symptoms:

⚠️ Difficulty breathing: open-mouth breathing or laboured breathing
⚠️ Fainting or repeated brief loss of consciousness
⚠️ Blue-tinged gums or lips, or pale colour

02How can you assess an abnormal sign? Home observation points and emergency criteria

At home, recording specific changes and videos can help your vet assess the condition more quickly and prioritise the right tests.

Record how often coughing occurs, when episodes happen and what triggers them
Watch the breathing rate and effort level both at rest and during activity
Track changes in mood, activity level and exercise tolerance
Note appetite, nausea, regurgitation or difficulty swallowing
Use your phone to record videos of coughing, panting or fainting episodes
If signs worsen or any emergency warning signs appear, seek veterinary care promptly

03How will a vet make the diagnosis? Common tests

At the clinic, the vet will mainly use a physical examination and imaging to confirm the defect location, heart workload, and whether there are lung or whole-body complications.

Physical examination

listening to the heart and lungs, checking mucous membrane colour and temperature

Chest X-rays

assessing heart size and any pulmonary oedema or congestion

Echocardiography

confirming the location and size of the defect and the direction of blood flow

Blood tests and biochemistry

assessing overall health and organ function

CT or advanced imaging may be performed if needed for surgical assessment

An examination at a specialist hospital with echocardiography equipment is recommended

04How is it treated and cared for after diagnosis? Medication, diet adjustments and care guide

Treatment and follow-up depend on the severity of the condition. Management may involve medication, interventional procedures or surgery, and both post-operative and conservative care require regular rechecks and imaging follow-up.

Medication may be used to control heart failure or reduce symptoms, with regular rechecks and dose adjustments
Interventional or surgical repair may be considered in some cases after specialist assessment
Diet control and weight management can help reduce strain on the heart
Continue monitoring breathing, activity level and appetite changes at home
Follow-up echocardiography or chest X-rays should be done on schedule to assess response to treatment
Referral to a veterinary cardiologist and regular follow-up visits may be needed

05What should you prepare before seeing the vet? Key details that help the vet clarify the cause quickly

List when the symptoms started and specific records of how they have changed

Prepare videos of coughing, panting or fainting for the vet to review

Record recent changes in eating, toileting and activity level

Bring a list of current medications or supplements

Bring previous imaging or test reports, if available, for comparison

Use a secure carrier and book a cardiology appointment in advance

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.