Heartworm in your pet? See a cardiologist!

April is heartworm awareness month! At BBVSH, our board-certified cardiologists are specially trained to treat heartworm disease. Our cardiology resident, Dr. Jennifer Gamracy, shared what pet owners should look for and how a cardiologist treats heartworm disease.

Microfilaria (baby heartworms) in a blood sample from a heartworm positive patient.

 What is heartworm disease, and can my pet get it?

Heartworm disease is primarily found in dogs but can also be found in cats and even ferrets! It is most commonly found in the Southern USA, Mexico, and other “tropical” climates, but can also found in the Okanagan region of BC and southern Ontario, Quebec, and Manitoba. For heartworm, the old saying “an ounce of prevention is worth a pound of cure” is very appropriate. Infection can be easily prevented with several over-the-counter products but once the parasite enters the bloodstream, it is not easy to cure.

Infection starts when a pet is bitten by a mosquito carrying the larval form of the disease. Then it takes about 6 months for the larvae to develop into adult worms. These adult worms can be up to a foot long and live in the blood vessels inside an animal’s lungs. They can live for 5-7 years in dogs and will produce “baby worms” called microfilariae. The microfilariae travel through the bloodstream which can be ingested by mosquitos and passed onto another animal



What are the signs of heartworm infection?

Irritation of the blood vessels in the lungs from the worms can cause coughing, exercise intolerance, decreased appetite, and weight loss. In more severe infections, signs like abdominal effusion or collapse from heart failure may be seen.

My pet has heartworm – should I see a cardiologist?

In BC, where heartworm is less common, infected dogs are often referred to a cardiologist or internal medicine specialist. In places where heartworm is common, treatment is often done by general practice veterinarians..

What will the cardiologist do?

Adult heartworms removed from a 12 lb dog.

When your pet sees a cardiologist, they will do a scan called an echocardiogram (ultrasound of the heart) to determine if there are any heartworms within the heart itself. If this occurs, it can cause a life-threatening condition called caval syndrome. The only treatment at this stage is surgical removal of the worms.

If the worms have not yet invaded the heart, your pet will be treated with a medical protocol laid out by the American Heartworm Society. There are several stages to treatment: first, we weaken the worms with oral antibiotics, then kill them with three separate injections. During the whole procedure (at least five months), your pet will be under extremely strict rest. If they move or run around too much, there is a risk of a dead worm blocking off a blood vessel causing severe complications. The protocol takes a long time, but is worth it – over 98% of dogs will be heartworm negative after going through the protocol, and the cardiology team will be with you every step of the way!

Where can pet owners go for more information?

The American Heartworm Society website has many resources for vets and pet parents – www.heartwormsociety.org

How do I find out more about BBVSH cardiology services?

Please visit our cardiology service page. Owners can also request a referral.


What can we help you find?