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
Other less common causes include
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.
Symptoms
There may be few symptoms of cor pulmonale until the disorder is quite advanced. When symptoms do occur, people describe
Symptoms of heart failure, such as swelling (edema) in the legs and progressively worse shortness of breath, also develop.
Diagnosis
A number of tests are available to help doctors diagnose cor pulmonale, but the diagnosis is often suspected on the basis of the physical examination. For example, by listening through a stethoscope, doctors can hear certain characteristic heart sounds that occur when the right ventricle becomes strained. The legs also become swollen, and veins in the neck enlarge.
Chest x-rays can show the enlarged right ventricle and pulmonary arteries.
Doctors evaluate the function of the left and right ventricles with echocardiography, radionuclide studies, and cardiac catheterization (to measure pressures in the heart chambers and lung arteries).
