What are the common early signs of canine dilated cardiomyopathy?

Early signs may include a slight drop in energy, poorer exercise tolerance, or reduced appetite. Some dogs may also cough or breathe faster while sleeping. If signs persist or worsen, consult your vet.

What tests will the vet do to confirm a heart problem?

Common tests include a physical examination with auscultation, chest X-rays, echocardiography, and blood biochemistry. These help assess heart size, heart function, and whether lung problems are also present.

How often will my dog need follow-up visits after diagnosis?

Follow-up timing depends on the severity of the condition. Stable cases may be reviewed every 3-6 months; if symptoms change or medication is being adjusted, your vet may recommend more frequent visits.

What information should I bring to the vet appointment?

Bring videos of the symptoms, records of when signs started, breaths per minute, previous test reports, and a current medication list. This helps your vet assess your dog more quickly.

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

Canine Dilated Cardiomyopathy in Dogs: Breathing Changes, Heart Tests & Care [2025]

Canine dilated cardiomyopathy is more common in large-breed dogs and requires echocardiography and blood tests for diagnosis. Early detection and ongoing medication can help slow disease progression.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: ACVIM, WSAVA, Taiwan Veterinary Internal Medicine Society

When to See a Vet

Seek Emergency Care Immediately

•Persistent open-mouth breathing or severe rapid breathing
•Repeated fainting or frequent episodes of brief loss of consciousness
•Blue or pale discoloration of the lips or gums

Schedule a Clinic Visit Soon (within 24–72 hours)

•Persistent lethargy and decreased activity level
•Noticeably faster breathing at rest compared to normal
•Frequent or ongoing coughing episodes

01What symptoms suggest something is wrong?

Canine dilated cardiomyopathy commonly causes reduced energy, appetite changes, and abnormal breathing. Early on, signs may be limited to mild tiredness; as it progresses, coughing, faster breathing, or fainting may occur.

Low energy or a clear drop in activity
Ongoing poor appetite or weight loss
Occasional or persistent coughing, especially worse at night or when lying down
Faster breathing at rest or panting
Reduced exercise tolerance, tiring easily or playing less

Seek emergency care immediately if you notice the following symptoms:

⚠️ Difficulty breathing or open-mouth panting
⚠️ Fainting or briefly losing consciousness
⚠️ Gums or lips turning blue, purple, or very pale

02How can I assess changes at home? Key observations and when it may be urgent

Careful home observation and records help your vet assess urgency and plan the right tests more quickly.

Record when changes in mood and activity level first appeared
Monitor and measure daily appetite and food intake
Weigh your dog at the same time each day and record the trend
Track coughing frequency, when episodes happen, and how long they last
Count breaths per minute while your dog is resting quietly and note the situation
If you notice anything abnormal, take videos of activity and breathing to bring to the appointment

03How will the vet diagnose it? Common tests

At the clinic, your vet will start with a physical examination and may use imaging and blood tests to assess heart and lung function.

Physical examination

listening to the heart and lungs and assessing circulation

Chest X-rays

checking heart size and lung changes, such as fluid leakage or pulmonary oedema

Echocardiography

assessing heart muscle thickness, chamber size, and pumping function

Blood tests and biochemistry

checking organ function and possible metabolic abnormalities

Urinalysis or, when needed, advanced imaging such as CT to rule out other problems

04How is it treated and managed after diagnosis? Medication, diet changes, and care

Treatment aims to stabilise clinical signs and slow worsening of the disease. Long-term medication and regular monitoring are usually needed.

Closely monitor breathing and energy over the short term, with hospitalisation if needed
Hospital care may include oxygen support and treatment to stabilise circulation
Give medications consistently as directed by your vet and attend follow-up visits on schedule
Manage diet and body weight to reduce strain on the heart
Arrange regular echocardiograms and blood tests to track disease progression
Referral to, or follow-up with, a specialist hospital with cardiac testing capability may be recommended

05What should I prepare before seeing the vet? Key information that helps identify the cause

Record videos showing activity and breathing, from the side and close up

Write down when symptoms first appeared and how their frequency has changed

Measure and record breaths per minute while your dog is resting quietly

Note any fainting or loss of consciousness, including the time it happened

Bring previous test reports, imaging, and a current medication list

Book a specialist appointment that can perform echocardiography if needed

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.