Does coughing or rapid breathing always mean my cat has heartworm?

Not necessarily. Coughing or rapid breathing can come from many respiratory or heart conditions. A vet will need to assess your cat with chest imaging, blood tests, ultrasound and other tests to clarify the cause, so prompt veterinary assessment is recommended.

What information or videos should I bring to the appointment?

Bring symptom videos, ideally close-up side views, records of when the problem started, vomiting frequency and a medication list. If you have previous chest X-rays or ultrasound reports, bring those too, as they can speed up diagnosis and treatment decisions.

Can feline heartworm infection be prevented?

Prevention mainly involves reducing mosquito bites and speaking with your vet regularly. Preventive medication or mosquito-control measures may be available in some regions. Follow your vet's advice on the right option and dosing frequency.

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

Feline Heartworm Disease in Cats: Breathing and Vomiting Signs, Diagnosis, Treatment and Care [2025]

Feline heartworm disease is spread by mosquito bites and can cause breathing difficulty and heart-related problems. Treatment options in cats are limited and focus mainly on supportive care, so prevention is better than treatment.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: AHS, ACVIM, National Taiwan University Veterinary Hospital

When to See a Vet

Seek Emergency Care Immediately

•Severely labored breathing that does not improve on its own
•Persistent open-mouth breathing or continuous audible groaning
•Repeated collapse or frequent brief loss of consciousness

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

•Repeated vomiting with significantly reduced appetite lasting more than one day
•Frequent dry coughing or occasional cough with rapid breathing
•Noticeably decreased activity level and easy fatigue

01What symptoms suggest something is wrong?

When cats are infected with heartworm, signs are usually related to the airways and heart, and they are often non-specific.

Repeated vomiting or a clear drop in appetite, which may come and go
Persistent or intermittent dry coughing, coughing up mucus or bringing up white foam
Faster breathing, wheezing or open-mouth breathing
Weakness, reduced activity or poorer exercise tolerance
An irregular heart rhythm may occur, or a heart murmur may be heard during auscultation

Seek emergency care immediately if you notice the following symptoms:

⚠️ Rapid breathing, open-mouth breathing or difficulty breathing
⚠️ Repeated fainting or brief loss of consciousness
⚠️ Severe lethargy or inability to eat normally

02How can I assess the problem at home? Key observations and when it is an emergency

Observing and recording key details at home can help your vet assess the condition and plan tests more quickly.

Record how often your cat vomits, what the vomit looks like and when it happens
Take videos of coughing and breathing, from the side and close up, to show your vet
Measure and record the resting respiratory rate and whether open-mouth breathing occurs
Note when changes in energy, activity and appetite started and how they have progressed
Watch for changes in urination or defecation, and whether there has been any fainting or lameness
Bring the videos and observation notes to the specialist appointment for your vet to review

03How will the vet make a diagnosis? Common tests

After arrival at the clinic, your vet will start with a physical examination and combine it with imaging and laboratory tests to assess the heart, lungs and overall health.

Full physical examination

listening to the heart and lungs and assessing breathing and circulation

Blood tests and biochemistry

assessing organ function and inflammatory response

Chest X-rays

checking for lung changes and changes in heart size

Echocardiography, also called cardiac ultrasound

assessing heart structure and function

CT scan or further imaging may be arranged if needed

A hospital with cardiology expertise or comprehensive imaging equipment is recommended

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

Treatment includes acute supportive care and long-term monitoring. At-home care and regular rechecks are important for the prognosis.

During the acute stage, fluids, oxygen and other supportive care may be needed to stabilise your cat
Your vet will assess the case and arrange suitable medication or procedures
Dietary management and restricted activity can reduce the workload on the heart and lungs
Regular rechecks are needed to monitor cardiac ultrasound and blood test results
At-home care should include ongoing monitoring of breathing, energy level and appetite
Referral to a cardiology hospital may be needed for advanced follow-up

05What should I prepare before seeing the vet? Key details that help your vet identify the cause quickly

Record videos of the symptoms and note the filming time and how often they occur

Record when the problem started, how the symptoms fluctuate and any possible triggers

Measure and record the resting respiratory rate and whether open-mouth breathing occurs

If your cat has fainted, describe the number of episodes, how long they lasted and the situation when they happened

Bring a list of current medications and any previous test results or imaging reports

When visiting a clinic, prioritise a hospital with cardiac diagnostic capabilities

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.