Chronic cor pulmonale

Pathophysiology of chronic cor pulmonale:

The Pathophysiology varies with the cause. COPD is discussed here.

• Pulmonary vascular resistance (PVR) is increased because of loss of pulmonary vascular tissue and because of pulmonary vasoconstriction caused by hypoxia and acidosis.
• The increased PVR leads to pulmonary HT
• The pulmonary HT becomes chronic and progressively more severe
• Right ventricular function is progressively compromised because of the increased pressure load
• Hypoxia further impairs right ventricular function and, as it develops, left ventricular function is also depressed

Clinical features:

Symptoms:

• Chest pain
• Exertional dyspnoea
• Syncope
• Fatigue
• Sudden death

On examination:

• Right ventricular (parasternal) heave
• Loud pulmonary component to the second heart sound
• Mid-systolic ejection murmur
• Early diastolic murmur (due to pulmonary regurgitation)
• Pansystolic murmur (if tricuspid regurgitation develops)

Investigations:

CXR:

• May show right ventricular enlargement and right atrial dilatation
• Prominent pulmonary artery

ECG:

• Right axis deviation (indicating right ventricular hypertrophy)
• Tall peaked T waves in lead II (P pulmonale)

Echocardiography:

• Will usually demonstrate right ventricular dilatation and/or hypertrophy
• May also reveal the cause of the pulmonary hypertension
• If no other cause is found, then the diagnosis of primary pulmonary hypertension is made. This disease typically affects young females (20-35 years)

Treatment:

Treatment is determined by the underlying condition

Diuretic therapy in right ventricular failure:

• Use with care as excessive fluid depletion will result in a reduced output from the impaired ventricle

Oxygen therapy

Primary pulmonary hypertension:

• Treated with anticoagulation (because the possibility of recurrent thromboembolism can seldom by fully excluded)
• Vasodilators (e.g. verapamil) are sometimes of symptomatic benefit
• Usually there is a progressive downhill course. Heart and lung transplantation is recommended for young patients