How do we diagnose cor pulmonale?

Diagnosing Cor Pulmonale

The diagnosis of cor pulmonale requires a combination of clinical evaluation, electrocardiography, imaging studies (particularly echocardiography), and in some cases right heart catheterization, with echocardiography being the most valuable non-invasive diagnostic tool. 1

Clinical Evaluation

• Physical examination should focus on detecting signs of right ventricular dysfunction including:

  • Raised jugular venous pressure
  • Right ventricular heave
  • Loud pulmonary second sound
  • Tricuspid regurgitation murmur
  • Peripheral edema
  • Central cyanosis 1

• In advanced disease, look for cyanosis, cor pulmonale signs (accentuated pulmonic second sound, right ventricular heave), and peripheral edema 2

• Note that physical examination has poor sensitivity for detecting moderate cor pulmonale and may be challenging in patients with obesity or other comorbidities 1

Electrocardiographic Assessment

• ECG findings suggestive of cor pulmonale include:

  • Right axis deviation for age
  • Right atrial enlargement
  • Right ventricular hypertrophy 2, 1

• In acute cor pulmonale, look for specific patterns:

  • S1Q3T3 pattern
  • S1S2S3 pattern
  • Negative T waves in right precordial leads
  • Transient right bundle branch block
  • Pseudoinfarction pattern 1

Imaging Studies

Chest Radiography

• Look for:
  • Enlargement of central pulmonary arteries
  • Right heart chamber enlargement
  • Measurement of right interlobar artery 1
  • Lung hyperinflation and hyperlucent areas with peripheral trimming of vascular markings (in COPD) 2

Echocardiography

• The most valuable non-invasive diagnostic tool for cor pulmonale with specific criteria:
  • Right ventricle/left ventricle basal diameter ratio >1.0 indicates right ventricular enlargement 1
  • Flattening of the interventricular septum (left ventricular eccentricity index >1.1) suggests right ventricular pressure overload 1
  • Right ventricular outflow Doppler acceleration time <105 msec and/or midsystolic notching suggests increased pulmonary vascular resistance 1
  • Early diastolic pulmonary regurgitation velocity >2.2 m/sec indicates elevated pulmonary artery pressure 1
  • Pulmonary artery diameter >25 mm suggests pulmonary hypertension 1
  • Tricuspid regurgitation velocity >3.4 m/s (corresponding to PA systolic pressure >50 mmHg) indicates likely pulmonary hypertension 1
  • Inferior vena cava diameter >21 mm with decreased inspiratory collapse (<50% with a sniff or <20% with quiet inspiration) suggests elevated right atrial pressure 1
  • Right atrial area (end-systole) >18 cm² indicates right atrial enlargement 1

Advanced Imaging

• MRI can be valuable for:
  • Assessing right ventricular size and function
  • Evaluating septal flattening and delayed contrast enhancement of septal insertions
  • Measuring right ventricular end diastolic volume index (which has prognostic value) 2
  • Quantitative contrast-enhanced MR angiography for assessment of pulmonary hypertension severity 2

Hemodynamic Assessment

• Right heart catheterization remains the gold standard for confirming pulmonary hypertension with mean pulmonary arterial pressure (mPAP) ≥25 mmHg 1

• Recent guidelines have revised the definition of pulmonary hypertension from mPAP >25 mmHg to >20 mmHg, which may facilitate earlier detection of cor pulmonale 3

Integrated Diagnostic Approach

• Initial suspicion based on symptoms and signs in patients with known lung disease 1

• Screening with ECG and chest radiography to detect signs of right heart enlargement 1

• Echocardiographic assessment to confirm right ventricular enlargement and estimate pulmonary artery pressure 1

• Severity classification based on tricuspid regurgitation velocity:

  • ≤2.8 m/s, PA systolic pressure ≤36 mmHg: no cor pulmonale
  • 2.9–3.4 m/s, PA systolic pressure 37–50 mmHg: mild cor pulmonale

  • 3.4 m/s, PA systolic pressure >50 mmHg: moderate to severe cor pulmonale 1

Common Pitfalls and Considerations

• Echocardiographic assessment may be challenging in patients with hyperinflated lungs due to COPD, but subcostal views can usually provide adequate visualization 1

• Awake oxygen saturation levels do not accurately predict hypoxemia during sleep, which is important in monitoring patients with cor pulmonale 2

• In patients with COPD, the signs and symptoms of pulmonary hypertension can be masked by the respiratory disease 4

• Standard treatment of left ventricular failure could have adverse effects in patients with cor pulmonale, highlighting the importance of accurate diagnosis 4

• Noninvasive techniques like echocardiography, radionuclide ventriculography, and MRI have largely replaced invasive pulmonary artery catheterization in the initial assessment of cor pulmonale 5