Right ventricular enlargement in heartworm disease.

Area of Science:

• Veterinary Cardiology
• Parasitology
• Canine Cardiology

Background:

• Dirofilaris immitis (heartworm) is a significant parasitic threat to canine health.
• Cardiac remodeling, particularly right ventricular changes, is a known complication of heartworm disease.
• The sequence of cardiac adaptation, specifically dilation versus hypertrophy, requires further elucidation.

Purpose of the Study:

• To evaluate the size of the right ventricle in dogs naturally infected with Dirofilaris immitis.
• To determine whether right ventricular dilation or hypertrophy is the initial cardiac response to heartworm infestation.
• To compare diagnostic modalities for assessing right ventricular size in this context.

Main Methods:

• Thoracic radiography was employed to assess right ventricular size.
• Electrocardiography was used to detect signs of cardiac abnormality.
• Right ventricular free wall weights were measured post-mortem.

Main Results:

• Radiographic evaluation indicated that 13 out of 15 dogs exhibited enlarged right ventricles.
• Electrocardiography and right ventricular free wall weights did not reveal evidence of right ventricular hypertrophy in any of the dogs.
• Findings suggest right ventricular dilation occurs independently of hypertrophy in response to Dirofilaris immitis.

Conclusions:

• Canine Dirofilaris immitis infestation leads to right ventricular dilation.
• This dilation appears to precede the development of right ventricular hypertrophy.
• Radiography is a sensitive tool for detecting early right ventricular enlargement in heartworm disease.