Cor pulmonale

Cor pulmonale is a serious condition in which the lower right chamber of the heart (the right ventricle) becomes enlarged and eventually fails as a result of chronic lung disease.

Normally, little effort is necessary to pump blood from the right ventricle to the lungs, as compared with the force necessary to pump blood from the left ventricle to the remainder of the body. As a result, the heart muscle of the right ventricle is comparatively weaker than that of the left ventricle.

When lung function is impaired, as a result of lung disease, the right ventricle must work harder to overcome increased resistance to blood flow from the heart through the branches of the pulmonary artery (pulmonary hypertension). Because it is harder to pump blood to the lungs, blood flow from the right ventricle is slowed down, leading to an accumulation of blood within the right ventricle. Though the heart muscle becomes enlarged (hypertrophied) in an attempt to compensate, it eventually fails (right-sided heart failure).

Acute cor pulmonale is an emergency situation arising from a blood clot in the lungs (pulmonary embolism). With prompt medical attention, it is usually reversible.

Chronic cor pulmonale develops gradually. It is associated with chronic obstructive lung diseases such as emphysema, silicosis, and pulmonary fibrosis (replacement of normal lung tissue with fibrous scar tissue) following a prolonged infection.

History: Symptoms include shortness of breath with exercise, chronic cough that produces sputum, blue tinge around the mouth and fingernails (cyanosis), wheezing, weakness, tiring easily, and swelling of the lower extremities (edema).

Physical exam may reveal distended veins in the neck, enlarged and tender liver, swelling of lower extremities (edema), and abdominal swelling and discomfort due to fluid collection in the abdominal cavity (ascites).

Tests to evaluate heart function may include chest x-ray to detect an enlarged right ventricle and pulmonary artery, echocardiogram (a technique in which ultrasound is used to visualize dimensions of the ventricles and exclude left ventricle dysfunction), and electrocardiogram (to record the electrical activity of the heart, identifying right ventricle enlargement).

Pulmonary function tests usually confirm the underlying lung disease. Pulmonary angiography (x-ray of blood vessels in the lungs after injection with a contrast medium) can be used to detect pulmonary embolism (blood clot in the lungs), but carries increased risk when performed on individuals with pulmonary hypertension.

Treatment is directed at relieving the underlying lung or cardiac disorder that caused the condition. When due to pulmonary embolism, small clots may be dissolved with the use of thrombolytic drugs. Emergency surgery may need to be performed to remove a large embolus.

Chronic obstructive lung disease is usually treated by use of bronchodilators to widen airways of the lungs and aid in breathing. Oxygen therapy may also be necessary.

In severe cases, the use of a mechanical ventilator may be required to reduce breathing difficulties and ensure adequate oxygen for the body's needs. In addition, treatment may include diuretics (to increase urine production and reduce excess body fluids), salt and fluid restriction, and adequate rest.

Unless atrial fibrillation is present, digitalis (a drug that increases the force of the heart's muscle contraction, enabling the heart to pump more blood) is not indicated.