Cor pulmonale refers to altered structure and function of the right ventricle due to chronic lung disease-related pulmonary hypertension (group 3). The mechanism involves hypoxic vasoconstriction which leads to permanent changes in the pulmonary vascular bed. Cor pulmonale generally progresses slowly, although acute onset or exacerbation can occur and may be fatal.

Some authors include pulmonary embolism and pulmonary arterial hypertension in the etiology.

Clinical presentation

The condition is under-diagnosed because symptoms occur late:

• dyspnea and hypoxemia are disproportionate to the severity of lung disease

• arterial oxygen decreases rapidly on exercise

• exercise induces chest pain or syncope

• jugular venous pressure is elevated and peripheral edema develops

• there are signs of pulmonary hypertension on auscultation and ECG

• there is disproportion reduction in DLCO relative to severity of lung disease

• main pulmonary enlarges on CT and peripheral arteries become attenuated

ECG

• dominant R wave in lead V1 ¹⁰

  • defined as an R wave height > 7 mm or R/S > 1

  • accompanied by dominant S waves in lead V6

• right axis deviation

• secondary repolarization abnormalities

  • simultaneous involvement of the right precordium (V1-4) and inferior limb leads (II, III, aVF)

  • depressed ST segments with T wave inversion

• right atrial enlargement

Pathology

• The pulmonary vascular resistance, under normal circumstances, is one tenth that of the systemic arteries. Lung parenchymal changes (e.g COPD, fibrosis) resulting in chronic hypoxemia stimulates smooth muscle proliferation within the pulmonary arteries, which in turn increases the pulmonary vascular resistance. This increases the strain on the right ventricle which has to pump against a greater pressure, resulting in its dilatation/hypertrophy.¹¹

Etiology

• chronic obstructive pulmonary disease

• pulmonary manifestations of cystic fibrosis

• interstitial lung disease

• acute respiratory distress syndrome: for acute cor pulmonale

• pulmonary sarcoidosis

• pulmonary embolism

• pulmonary arterial hypertension

Radiographic features

Plain radiograph

• central pulmonary artery enlargement ⁷

• changes consistent with the underlying pulmonary disease as outlined above

CT

• lung disease such as combined pulmonary fibrosis and emphysema

• dilated main pulmonary artery

• hypertrophied RV

• dilated RV and RA

• contrast medium reflux into dilated IVC and hepatic veins

• horizontal blood/contrast medium level in the IVC indicates slow flow

Ultrasound

Echocardiography

May show dilatation of the right ventricular cavity or thickening of the right ventricular free wall ⁶.

Treatment and prognosis

Cor pulmonale generally carries a poor prognosis. Long-term oxygen therapy is often considered the main treatment option.

History and etymology

From the Latin, cor: 'heart', and pulmonale, 'relating to the lungs', ultimately from the Latin pulmo meaning 'lung'. Therefore 'heart secondary/relating to the lungs'.

See also

• right heart failure

• right heart strain