What is corpulmonale (pulmonary heart disease)?

Cor Pulmonale: Definition and Clinical Significance

Cor pulmonale is defined as right ventricular hypertrophy and/or dilation caused by pulmonary hypertension due to diseases affecting lung function and structure. 1

Definition and Pathophysiology

• Cor pulmonale represents the structural and functional alterations of the right ventricle (RV) resulting from primary disorders of the respiratory system 2
• It is characterized by increased pulmonary vascular resistance leading to right ventricular pressure overload, hypertrophy, and eventually right heart failure 3
• The condition can be classified as acute or chronic based on the speed of onset and subsequent effects on the right ventricle 1

Hemodynamic Basis

• Pulmonary hypertension (PH) is the underlying mechanism of cor pulmonale, defined as a mean pulmonary arterial pressure (mPAP) ≥25 mmHg at rest as measured by right heart catheterization 4
• Recent guidelines have suggested redefining PH with a lower threshold of mPAP >20 mmHg 5
• In cor pulmonale, PH is typically pre-capillary, characterized by mPAP ≥25 mmHg with pulmonary wedge pressure (PWP) ≤15 mmHg and pulmonary vascular resistance (PVR) ≥3 Wood units 4

Etiological Classification

Cor pulmonale can result from various conditions that affect the lungs and pulmonary circulation:

• Group 3 PH (PH due to lung diseases and/or hypoxia) is the most common cause of cor pulmonale, including: 6

  • Chronic obstructive pulmonary disease (COPD)
  • Interstitial lung disease
  • Sleep-disordered breathing
  • Alveolar hypoventilation disorders
  • Chronic exposure to high altitude
  • Developmental lung diseases

• Other causes include: 6

  • Group 4 PH (Chronic thromboembolic pulmonary hypertension)
  • Group 1 PH (Pulmonary arterial hypertension) in some cases
  • Group 5 PH (PH with unclear/multifactorial mechanisms)

Pathophysiological Mechanisms

• In COPD, the most common cause of cor pulmonale, multiple mechanisms contribute to PH development: 7

  • Hypoxic pulmonary vasoconstriction, a direct response to alveolar hypoxia
  • Vascular remodeling affecting all layers of pulmonary arterial walls
  • Destruction of the pulmonary vascular bed due to emphysematous changes
  • Increased effective pulmonary vascular resistance due to erythrocytosis in chronic hypoxemic states

• The right ventricle responds to increased pressure load through: 7

  • Initial compensatory right ventricular hypertrophy
  • Development of isovolumic phases of contraction and relaxation
  • Progressive RV dilation
  • Eventually right ventricular failure

Clinical Presentation

• Symptoms are non-specific and mainly related to progressive right ventricular dysfunction: 6

  • Exertional shortness of breath
  • Fatigue and weakness
  • Angina and syncope
  • Dry cough and exercise-induced nausea/vomiting in some cases
  • Abdominal distension and ankle edema in advanced cases

• Physical examination findings may include: 6

  • Left parasternal lift
  • Accentuated pulmonary component of the second heart sound
  • Right ventricular third heart sound
  • Pansystolic murmur of tricuspid regurgitation
  • Diastolic murmur of pulmonary regurgitation
  • Elevated jugular venous pressure, hepatomegaly, ascites, and peripheral edema in advanced disease

Diagnostic Approach

• Electrocardiogram may show: 6

  • P pulmonale
  • Right axis deviation
  • Right ventricular hypertrophy and strain
  • Right bundle branch block
  • QTc prolongation

• Chest radiography findings include: 6

  • Central pulmonary arterial dilatation with "pruning" of peripheral blood vessels
  • Right atrial and right ventricular enlargement in advanced cases
  • Signs of underlying lung disease

• Echocardiography is crucial for diagnosis and monitoring: 1

  • Allows detection of right ventricular dysfunction at an earlier stage
  • Provides parameters with prognostic value
  • Enables assessment of treatment efficacy
  • Can differentiate between acute and chronic cor pulmonale

• Right heart catheterization remains the gold standard for confirming PH diagnosis 4

Clinical Significance and Prognosis

• Cor pulmonale is associated with higher mortality rates independent of other prognostic variables 3
• It limits peripheral oxygen delivery, increases shortness of breath, and reduces exercise endurance 3
• The median life expectancy from diagnosis in patients with idiopathic PAH, before disease-specific therapy, was only 2.8 years 4

Management Considerations

• Long-term oxygen therapy is the only treatment shown to improve survival in patients with COPD-related cor pulmonale 3
• Bronchodilators, particularly theophylline and beta-2 agonists, may have beneficial effects on pulmonary hemodynamics 3
• Diuretics and phlebotomy can improve symptoms in appropriate patients 3
• The role of pulmonary arterial hypertension-specific medications remains controversial and is not routinely recommended for COPD-related cor pulmonale 8

Understanding cor pulmonale as a consequence of pulmonary vascular disease is essential for appropriate management, with treatment primarily focused on the underlying respiratory condition and optimization of oxygenation.