What are the common symptoms of hypertrophic cardiomyopathy?

Common signs include persistent or night-time coughing, rapid breathing at rest, reduced exercise tolerance, and occasional fainting. If your dog's lips turn blue or breathing becomes difficult, seek veterinary care as soon as possible.

How do vets diagnose hypertrophic cardiomyopathy?

Diagnosis usually involves chest X-rays and an echocardiogram to assess heart size and wall thickness, along with an ECG and blood tests for a complete evaluation.

How often are follow-up visits needed after diagnosis?

Follow-up frequency depends on the condition. When stable, rechecks are often every 3-6 months; if the condition is unstable or medication has changed, more frequent visits may be needed as directed by your vet.

What records can I keep at home to help the vet?

You can record coughing frequency, resting respiratory rate, videos during activity, and changes in energy, appetite, and water intake, then bring these records to the appointment for your vet to review.

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

Hypertrophic Cardiomyopathy in Dogs: Breathing Changes, Echocardiography & Care [2025]

Canine hypertrophic cardiomyopathy causes thickening of the heart muscle that can affect heart function. Diagnosis requires an echocardiogram, and medication can help relieve symptoms.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: ACVIM, AAHA, Taiwan Veterinary Internal Medicine Association, National Taiwan University Veterinary Hospital

When to See a Vet

Seek emergency care immediately

•Persistent open-mouth breathing with rapid respiration that does not subside
•Repeated or sudden fainting or loss of consciousness
•Noticeably purple or pale gums or lips

Schedule a clinic visit promptly (within 24–72 hours)

•Frequent increased respiratory rate at rest
•Persistent or nightly recurring dry cough with no improvement
•Significantly reduced exercise tolerance, tires easily during walks

01What symptoms suggest something is wrong?

Dogs with hypertrophic cardiomyopathy often show changes in breathing and activity levels. Watch closely for signs of sudden worsening.

Persistent or night-time coughing, sometimes with episodes of breathlessness
Rapid breathing or panting while resting
Bluish lips or gums, which may indicate low oxygen levels
Reduced exercise tolerance, easy fatigue, or occasional fainting
A heart murmur or irregular heartbeat may be detected on auscultation

Seek emergency care immediately if you notice the following symptoms:

⚠️ Ongoing difficulty breathing or open-mouth breathing
⚠️ Repeated or sudden fainting, collapse, or loss of consciousness
⚠️ Gums or lips that are clearly blue, purple, or pale

02How can you assess abnormalities at home? Key observations and when to seek emergency care

Observing and recording changes in breathing, coughing, and activity at home can help your vet understand how the condition is progressing.

Record how often coughing occurs, when episodes happen, and any possible triggers
Measure your dog's resting respiratory rate and save videos for your vet
Take several short videos during walks or activity for reference
Track changes in energy, appetite, and water intake
Arrange a veterinary visit promptly if breathing or alertness worsens

03How will the vet diagnose it? Common tests

At the clinic, diagnosis is based on a physical examination supported by imaging and blood tests to assess heart structure and function.

Physical examination

listening to the heart, and measuring heart rate and respiratory rate

Chest X-rays

assessing heart size and checking the lungs for fluid build-up or pulmonary oedema

Echocardiography (ECHO)

measuring heart wall thickness and heart function

Electrocardiogram (ECG)

checking for arrhythmias or conduction abnormalities

Blood tests and biochemistry

assessing metabolism, kidney function, and effects on other organs

04What treatment and care are needed after diagnosis? Medication, diet changes, and home care

Treatment focuses on supportive care and long-term monitoring, with rechecks needed so management can be adjusted according to test results.

During an acute deterioration, oxygen therapy and hospital supportive care may be needed
Medication may be prescribed based on your vet's assessment, with regular monitoring of response
Manage diet and body weight to reduce strain on the heart
Restrict strenuous activity and adjust exercise gradually according to the condition
Attend regular rechecks and repeat ECHO or X-rays to monitor heart changes
Long-term follow-up at a specialist hospital that manages cardiac disease is recommended

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

Bring several videos of coughing or abnormal breathing for review

Record changes in exercise tolerance and when signs first appeared

If fainting has occurred, write down the situation and frequency

Bring previous test reports or imaging results, if available

List all current medications and supplements

Use a secure carrier or transport crate and book the specialist 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.