Cor pulmonale is a change in structure and function of the right ventricle of the heart as a result of a respiratory abnormality. Right ventricular hypertrophy (RVH) is the major change in chronic cor pulmonale although in acute cases dilation dominates. Dilation is stretching of the ventricle, the immediate result of increasing the pressure inside any elastic container. Ventricular hypertrophy is a response to a long-term increase in pressure in which additional muscle grows to allow for the increased contractile force required to move the blood against greater resistance. Both hypertrophy and dilation are the result of increased right ventricular pressure.
To be classified as cor pulmonale, the cause must originate in the pulmonary (lung) circulation system. Two major causes are vascular changes as a result of tissue damage (e.g. disease, low oxygen, chemical agents etc.), and chronic hypoxic pulmonary vasoconstriction*.
Left untreated, cor pulmonale can lead to right-heart failure and death.
* Hypoxic pulmonary vasoconstriction is a physiological phenomenon in which pulmonary arteries constrict in the presence of low oxygen levels without high carbon dioxide levels, redirecting blood flow to alveoli with higher oxygen tension. The process might at first seem illogical, since low oxygen levels should theoretically lead to increased blood flow to the lungs to receive increased gaseous exchange. However, constriction leads to increased bloodflow to better-aerated areas of the lung, which increases the total area involved in gaseous exchange.