Cor Pulmonale (Pulmonary Heart Disease)

What happens in cor pulmonale

The right side of the heart pumps blood through the lungs at low pressure. Its muscle wall is thin and is not built to push against resistance. When lung disease damages the small blood vessels or keeps oxygen levels low, those vessels narrow (low oxygen makes lung arteries constrict). Pressure in the pulmonary arteries rises, a state called pulmonary hypertension.

The right ventricle responds by thickening (hypertrophy) and then stretching (dilation). Eventually it cannot keep up. Blood backs up into the veins of the body, causing swelling of the legs, a swollen liver and sometimes fluid in the abdomen. The term "cor pulmonale" is reserved for right heart failure caused by lung or breathing problems. Right heart failure caused by left-sided heart failure or valve disease is not cor pulmonale.

Acute vs chronic cor pulmonale

Causes

• COPD: the commonest cause, mainly in people with severe disease and chronically low oxygen.
• Interstitial lung disease and pulmonary fibrosis, which destroy lung tissue and its blood vessels.
• Chronic blood clots in the lungs (chronic thromboembolic pulmonary hypertension).
• Breathing disorders during sleep: severe obstructive sleep apnea and obesity hypoventilation syndrome.
• Chest wall and muscle problems: severe scoliosis, neuromuscular diseases.
• Living at high altitude for long periods.
• Cystic fibrosis, bronchiectasis and other chronic lung infections.

Symptoms

Early symptoms overlap with the underlying lung disease, so cor pulmonale is often missed:

• breathlessness, first on exertion and later at rest
• tiredness and reduced exercise tolerance
• swelling of the ankles and legs that is worse by evening
• chest pressure or discomfort with effort
• light-headedness or fainting on exertion
• a full or aching feeling under the right ribs from a congested liver
• bloating or a swollen belly in advanced cases

A doctor may find raised neck veins, a loud second heart sound, a heave next to the breastbone, an enlarged liver and leg edema. Bluish lips (cyanosis) suggest low oxygen.

Diagnosis

1. Echocardiogram: the key test. It shows an enlarged or weak right ventricle and estimates lung artery pressure.
2. Blood tests: BNP or NT-proBNP (raised when the heart is strained), blood count (thick blood from chronic low oxygen), kidney and liver function.
3. Oxygen and carbon dioxide levels: pulse oximetry and arterial blood gas.
4. ECG: may show right ventricular strain.
5. Chest X-ray and CT: show lung disease and enlarged lung arteries. CT pulmonary angiography or a V/Q scan looks for clots.
6. Lung function tests and an overnight sleep study if sleep apnea is suspected.
7. Right heart catheterization: measures pressures directly and is the gold standard when the diagnosis or treatment plan depends on exact numbers.

Treatment

The goal is to lower the strain on the right heart by improving oxygen and treating the lung problem.

• Long-term oxygen therapy: for people whose oxygen stays low at rest, oxygen used at least 15 hours a day improves survival in COPD. It relaxes the lung arteries.
• Diuretics (water pills): reduce leg swelling and fluid overload. They need careful dosing and blood test monitoring.
• Treating the lung disease: inhalers, pulmonary rehabilitation, stopping smoking, and vaccines against flu, COVID-19 and pneumococcus to prevent flare-ups.
• CPAP or non-invasive ventilation for sleep apnea and hypoventilation.
• Anticoagulants for chronic clots, and surgery or balloon procedures in selected cases.
• Pulmonary hypertension medicines are used only in specific situations, because in most lung-disease patients they can worsen oxygen levels.
• Lung transplant for selected people with end-stage disease.

Limiting salt and weighing yourself daily helps you spot fluid buildup early.

Outlook

The outlook depends on the underlying lung disease and how low oxygen levels are. Once the right heart fails, survival falls, which is why early oxygen treatment, stopping smoking and controlling sleep apnea matter. Treating the cause can stabilize the condition for years, and right heart function may partly recover if the trigger is reversible, as with sleep apnea or a treated clot.

Frequently asked questions

What is cor pulmonale in simple terms?

It is heart strain caused by the lungs. When lung disease raises pressure in the blood vessels of the lungs, the right side of the heart has to work harder, enlarges, and eventually fails, causing breathlessness and leg swelling.

What is the most common cause of cor pulmonale?

Chronic obstructive pulmonary disease (COPD) is the most common cause in adults, particularly when it causes persistently low oxygen levels. Other causes include pulmonary fibrosis, severe sleep apnea, obesity hypoventilation and chronic blood clots in the lungs.

Is cor pulmonale the same as right-sided heart failure?

Cor pulmonale is one type of right-sided heart failure: the type caused by lung disease or low oxygen. Right heart failure that results from left-sided heart failure or heart valve disease is not called cor pulmonale.

Can cor pulmonale be reversed?

Sometimes partly. If the cause is treatable, such as sleep apnea, low oxygen or a blood clot, right heart pressures and function can improve. When it follows advanced, irreversible lung disease, treatment aims to slow progression and ease symptoms.

How long can you live with cor pulmonale?

It varies widely with the cause, oxygen levels and how well treatment works. Many people live for years with good management, including oxygen therapy and stopping smoking. Your lung or heart specialist can give an estimate based on your test results.