Cor pulmonale

[Lanell]

Cor pulmonale is enlargement and thickening of the ventricle on the right side of the heart resulting from an underlying lung disorder that causes pulmonary hypertension (high pressures in the lungs). The enlargement and thickening of the right ventricle result in heart failure.
Pulmonary hypertension is a condition in which blood pressure in the arteries of the lungs (the pulmonary arteries) is abnormally high. Lung disorders can cause pulmonary hypertension in several ways.
When oxygen levels are low for a long time, pulmonary arteries constrict and their walls become thickened. This constriction and thickening increase the pressure in the pulmonary arteries. Lung disorders that damage or decrease the amount of lung tissue (for example, emphysema) also decrease the number of blood vessels in the lungs. The decreased number of blood vessels increases pressure in the remaining vessels.
The most common cause of cor pulmonale is

Chronic obstructive pulmonary disease (COPD)

Other less common causes include

Pulmonary embolism
Connective tissue diseases
Pulmonary interstitial fibrosis
Obesity with reduced ability to breathe

Once pulmonary hypertension develops, the right side of the heart has to work harder to pump blood through the lungs. The increased effort causes the heart muscle to become enlarged and thickened. If pulmonary hypertension continues long enough, the right side of the heart can no longer compensate by enlarging and thickening, and right-sided heart failure develops.
The failing right ventricle places a person at risk of pulmonary embolism because blood flow is abnormally low, so blood tends to pool in the legs. If clots form in the pooled blood, they may eventually travel to and lodge in the lungs, with dangerous consequences.