Content continues after advertisement

When Heartworms Migrate to the Heart in Dogs

Andrew R. Moorhead, DVM, MS, PhD, DACVM (Parasitology), University of Georgia

Parasitology

|
November/December 2021

Sign in to Print/View PDF

In the Literature

Romano AE, Saunders AB, Gordon SG, Wesselowski S. Intracardiac heartworms in dogs: clinical and echocardiographic characteristics in 72 cases (2010-2019). J Vet Intern Med. 2021;35(1):88-97.


FROM THE PAGE …

Intracardiac heartworms in dogs have been associated with caval syndrome. Further exploration is needed to, however, determine the exact percentage of cases that progress to caval syndrome, associated clinical signs, and echocardiographic parameters. Not all dogs with intracardiac heartworms have clinical signs, including hemoglobinuria, which is one of the hallmark signs of caval syndrome.

The aim of this retrospective study was to determine clinical and echocardiographic characteristics of intracardiac heartworm cases. Records from a veterinary teaching hospital from May 2010 to September 2019 were searched to identify dogs that were referred for caval syndrome, underwent heartworm extraction, or showed intracardiac heartworms on echocardiography.

Seventy-two dogs were included in the study and were divided into cases with low worm burden (a few worms; estimated, <5) and high worm burden (more than a few worms and filling the right atrium). A majority of cases (81%) had high worm burden; of these patients, 75% were small-breed dogs. This bias could be due to breed popularity, specifically Chihuahuas, but the authors postulated it could represent a clinically relevant phenomenon. 

Pulmonary hypertension, assessed via echocardiography, was likely in 93% of cases, possibly secondary to vessel blockage, and pigmenturia was detected in 43% of the likely pulmonary hypertension cases. Pigmenturia, anemia, and bilirubinuria were significantly more common in dogs with a high worm burden. Although only 25% of dogs met the criteria for caval syndrome, extraction of worms was performed in 65% of cases. This study emphasizes the importance of echocardiography for identifying intracardiac heartworms and determining worm burden, especially in small-breed dogs. If worm burden is high, regardless of whether the patient has caval syndrome, extraction of worms may be advantageous.


… TO YOUR PATIENTS

Key pearls to put into practice:

1

Echocardiography is key for diagnosing intracardiac heartworms and determining worm burden, especially in small-breed dogs.

2

Dogs with intracardiac heartworms have a high likelihood of pulmonary hypertension, although diagnosis can be confounded by the presence of a large number of worms.

 

3

Presence of intracardiac heartworms does not necessarily indicate caval syndrome; however, the patient may still benefit from extraction of worms.

Suggested Reading

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Clinician's Brief may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.

Podcasts

Clinician's Brief:
The Podcast
Listen as host Alyssa Watson, DVM, talks with the authors of your favorite Clinician’s Brief articles. Dig deeper and explore the conversations behind the content here.
Clinician's Brief provides relevant diagnostic and treatment information for small animal practitioners. It has been ranked the #1 most essential publication by small animal veterinarians for 9 years.*

*2007-2017 PERQ and Essential Media Studies

© Educational Concepts, L.L.C. dba Brief Media ™ All Rights Reserved. Terms & Conditions | Privacy Policy | Acceptable Use Policy