Cor pulmonale

1. Definition

Cor pulmonale (pulmonary hypertensive heart disease) = right ventricular hypertrophy + dilation (often with right-sided heart failure) caused by pulmonary hypertension arising from a primary disease of the lung parenchyma or pulmonary vasculature. By definition it excludes RV changes secondary to left-sided heart disease or congenital disease — although in practice left-sided HF is the commonest overall cause of right-sided failure.

2. Mechanism

Increased pulmonary resistance / pressure → ↑ RV workload → RV hypertrophy → over time the RV fails → blood backs up in systemic veins → ↑ venous pressure pushes fluid into tissues → peripheral edema, ascites, hepatic congestion.

3. Causes of right-sided failure / cor pulmonale

• Pulmonary hypertension (primary or secondary)
• Pulmonary embolism
• COPD, pulmonary emphysema
• Cystic fibrosis, interstitial pulmonary fibrosis
• Pulmonary edema
• Left-sided HF — most common cause overall: LV output ↓ → blood backs up through LA and lungs to the RV → ↑ pressure damages the right heart.

4. Acute vs chronic

	Trigger	RV change
Acute cor pulmonale	Usually massive pulmonary embolism (> 50% obstruction)	RV dilation only, no hypertrophy
Chronic cor pulmonale	Prolonged pressure overload (emphysema, interstitial fibrosis) in a setting of pulmonary hypertension	RV (and often RA) hypertrophied; dilation if failure supervenes

5. Emphysema → chronic cor pulmonale

Air trapping → ↑ alveolar pressure → septal destruction → coalescence into a large air sac (emphysema) → loss of surrounding capillary bed → ↑ effort to drive blood through the lungs → cor pulmonale chronicum.

6. Clinical features

• Edema of feet/ankles/legs → progressing to ascites and hepatic congestion.
• Dyspnea (nocturnal or on minimal exertion), cough, wheeze.
• Chest pain/discomfort, tachycardia.
• Chronic disease may add hydropericardium, bilateral hydrothorax, and generalized pitting edema (anasarca).

7. Predisposing disorders (by category)

Pulmonary parenchyma	Pulmonary vessels	Chest movement	Inducing arterial constriction
COPD, diffuse interstitial fibrosis, pneumoconiosis, cystic fibrosis, bronchiectasis	Recurrent thromboembolism, primary pulmonary hypertension, extensive pulmonary arteritis (e.g. Wegener), drug/toxin/radiation vascular obstruction, tumor microembolism	Kyphoscoliosis, marked obesity (Pickwickian), neuromuscular disease	Metabolic acidosis, hypoxemia, major airway obstruction, idiopathic alveolar hypoventilation

💡 High-yield: Cor pulmonale = right heart hypertrophy/dilation from a primary lung / pulmonary-vascular cause (excludes left heart & congenital disease). Acute = massive PE → RV dilation only; chronic = COPD/emphysema/interstitial fibrosis → RV hypertrophy. Backward failure → peripheral edema, ascites, hepatic congestion.