Cor pulmonale is hypertrophy, dilation, or malfunction of the right ventricle as a complication of pulmonary hypertension. It is generally classified into acute and chronic cor pulmonale. The chronic presentation is more common and can be caused by chronic obstructive pulmonary disease (COPD), interstitial lung diseases, pulmonary vascular diseases, or obstructive sleep apnea. The acute presentation can be caused by a sudden worsening of these diseases or by pulmonary embolism. In general, cor pulmonale can be caused by most causes of pulmonary hypertension excluding left heart disease (group 2 pulmonary hypertension) or congenital heart disease (part of group 1 pulmonary hypertension).

Symptoms of right heart failure include chest pain, fatigue, syncope, dyspnea on exertion, cough, hypoxemia, hemoptysis, cyanosis, peripheral edema, and other symptoms of congestion. Acute presentations may also present with pallor, diaphoresis, hypotension, and tachycardia due to the decrease in preload to the left ventricle. Chronic presentations are harder to detect and may present with clubbed fingernails, wheezing, crepitations, papilledema, tender hepatomegaly, and ascites.

Treatment and prognosis depend on the causal underlying disease.

Risk factors depend on the underlying disease. For instance, for group 1 idiopathic pulmonary arterial hypertension, risk factors include age and sex (ie, young women) and family history. Other causes of pulmonary hypertension, such as COPD or sleep apnea, may be caused by excessive smoking or obesity, respectively.

The World Health Organization (WHO) classifies pulmonary hypertension into 5 groups:

• Group 1: Pulmonary arterial hypertension
• Group 2: Pulmonary hypertension due to left heart disease
• Group 3: Pulmonary hypertension due to lung disease and/or chronic hypoxia
• Group 4: Pulmonary hypertension due to blood clots in the lungs
• Group 5: Pulmonary hypertension due to blood and other disorders