Shelter Dog Meal Donation Count:

Learn More

What Does A Heart Attack Look Like In Dogs?

Written by: Adri Sandoval
Adri Sandoval is the Special Projects Manager for iHeartDogs and iHeartCats. Her work has deepened her love for animals, fostering a strong passion for rescue and animal advocacy.Read more
| Published on October 23, 2023


Heart attacks in any breed of dog are considered very rare, very dangerous, and should be taken very seriously. When a heart attack occurs the heart is deprived of oxygen and nutrients, and could die. The affected chamber of the heart will no longer effectively pump blood to the body. If your dog has a congenital heart abnormality, heart disease, or genetic predisposition, he’s at a higher risk for a heart attack.

A heart attack requires emergency medical attention and can result in the unfortunate, sudden death of a pet.

Symptoms of Heart Attack in Dogs

A heart attack occurs very suddenly, and with little to no warning. Should your dog show any symptoms at all, it may be some of the following:

– Slight fever (over 103° Fahrenheit/39.4° Celsius)
– Vomiting
– Panting/abnormal breathing
– Increased heart rate (over 100 beats per minute for large breeds) (over 140 beats per minute for small breeds)
– Lethargy
– Head tilt
– Confusion/Anxiety
– Immobility
– Rigidity
– Seizure
– Collapse
– Sudden death

Causes of Heart Attack in Dogs

Any of the following might cause a heart attack:

 – Tumor: Tumor masses growing on or around the heart or blood vessels can block the flow of blood to the heart.
 – Hypothyroidism: Thyroid gland is responsible for converting food to fuel for the body. If it is not producing thyroxine hormone, it can cause a heart attack.
 – Nephrotic Syndrome: Kidney damage results in loss of protein involved in preventing blood clot formation. Blood clots are one cause of canine heart attack.
 – Bacterial infection: Infection in the body can lead to inflammation and blockage of blood flow to the heart muscle.
 – Vasculitis: Blood vessel inflammation as a result of infection, immune-mediated disease, or other injury to blood vessel linings. Results in narrowed vasculature.
 – Atherosclerosis: Plaque builds up in the arteries, restricting blood flow or rupturing arteries. Rare in dogs but has been reported in some breeds.
 – Coronary artery disease: Extremely rare in dogs. Occurs only with severe hypothyroidism and associated high serum cholesterol levels.

Diagnosis of Heart Attack in Dogs

If your dog is showing symptoms of a heart attack, calmly and carefully wrap him in a blanket to keep him tranquil. Keep calm and place your palm on the left side of his chest to feel for his heart rate. Count the number of beats in 15 seconds and multiply by 4 – this is his beats per minute. A normal heart rate for a dog will be 60 – 140 BPM. Get your dog to a vet.

If your dog collapses, don’t take the time to check for BPM, calmly wrap your dog in a blanket and get him straight to your vet.

Don’t attempt to give CPR unless you’ve been trained in pet CPR and know for certain that he needs it, as CPR can cause more harm than good if it’s given unnecessarily. Do not give water or food because there’s a chance he could vomit and asphyxiate. Keep any children away from your dog as pain and panic may cause him to lash out in fear.

Your vet will want to know what let up to the symptoms or collapse. They will listen to your dog’s heart for abnormal murmurs, pulse, or arrhythmia. Lab testing can reveal information about the way your dog’s heart is functioning and other possible causes of his symptoms.

 – Electrocardiography (EKG): Determines cardiac electrical impulses and measures arrhythmias.
 – Complete Blood Cell Count (CBC): Determines red and white blood cell count, can detect possible infection.
 – Biochemistry: Examines kidney and liver function.
 – Urinalysis: Examines kidney and metabolic function.
 – Thyroid: Examines thyroid gland function.
 – Echocardiography: Detects fluid or masses around the heart, heart valve function, heart muscle, and pericardial health.
 – Chest X-ray: Determines size of heart, fluid around heart, possible masses.

A Holter monitor may be suggested to monitor heart health at home. The monitor looks like a sleeve your dog would wear for 24 hours with electrodes taped onto the chest. Heart rhythms are recorded during rest, exercise, and stress and analyzed for abnormal heart activity.

Treatment of Heart Attack in Dogs

Depending on how serious the attack was, initial treatment might be resuscitation and supportive care. The goal is to regain normal heart activity. Medication may be used to thin the blood to make it easier for it to circulate. Your dog may need to be hospitalized to monitor his heart activity until vet staff is confident that your dog is stable.

There are several medications your vet might prescribe for your dog’s heart abnormalities, depending on the cause. There are also pacemaker implants available for dogs predisposed to heart problems. Surgery might be required to remove any mass that causes an obstruction of the blood flow to or from the heart. Thyroid replacement medications may be prescribed should his heart attack have been caused by a thyroid issue. A vet may prescribe medication or a change in diet for dogs with renal disease. Antibiotics can prevent further damage to vessels and heart lining due to infection or inflammation.

The potential for recurrence will depend on the cause of the problem and the severity of the heart attack.

Recovery of Heart Attack in Dogs

Many pets live long, happy lives after heart attacks, especially if they’re diagnosed and treated early. He may require treatment for the remainder of his life, particularly in cases of hypothyroidism, renal or heart disease. Your pet may need regular heart monitoring from his vet to ensure that he’s stabilized.

Your vet may ask you to restrict his activity while he regains normal heart function. You may want to become familiar with what his normal heart rate and breathing is like so that it becomes easier for you to detect issues should they arise again.

Recent Articles

Interested in learning even more about all things dogs? Get your paws on more great content from iHeartDogs!

Read the Blog

Leave a Comment