Introduction

The heart becomes diseased as a result of an abnormality in the lungs. Chronic pulmonary disease raises pulmonary resistance and results in right heart enlargement.

Causes include:

  • Primary chronic lung disease E.g. Fibrosis.
  • Thromboembolic obstruction of pulmonary arterioles E.g. metastatic neoplasia, lungworm in dogs.
  • Impairment of repiratory motion E.g thoracic trauma.

Grossly, the right heart is dilated with pulmonary and peripheral oedema.

Pulmonary thromboembolism from neoplasia, heart worm disease, and other factors can cause cor pulmonale by blocking the pulmonary vessels with emboli leading to increased pulmonary arterial pressures and ultimately right sided heart failure.