How cor pulmonale develops
The pathology begins with impaired pulmonary ventilation and respiratory failure. This leads to a decrease of oxygen in the alveoli (alveolar hypoxia). In response, a reflex vascular spasm (vasoconstriction) occurs. Initially, this spasm is localized in poorly ventilated areas to redirect blood to healthy zones. However, over time, the spasm extends to most pulmonary circulation vessels.
As a result, pulmonary hypertension develops. Pressure in the pulmonary artery exceeds normal limits (systolic: 15–30 mm Hg, diastolic: 5–15 mm Hg). This increases the afterload on the right ventricle. Initially, it responds with compensatory hypertrophy, and later, exhausting its reserves, it enlarges (dilation).
The increase in vascular resistance is also exacerbated by two factors:
- Rheological: secondary polycythemia develops, and blood becomes more viscous.
- Mechanical: frequent increases in intra-alveolar pressure (for example, during severe coughing fits during exacerbations) compress small vessels.
Clinical presentation
The disease may remain occult for a long time as symptoms merge with those of the underlying lung disease. The course is undulating: the condition sharply deteriorates when pulmonary infections supervene.
Typical patient complaints:
- Dyspnea, which is more pronounced than expected for the current state of the lungs.
- Retrosternal chest pain of a pressing nature. It is important to understand that this is not myocardial ischemia, but a consequence of overstretching of the pulmonary artery.
- Fatigue and tachycardia (asthenic syndrome).
- Dizziness and fainting (syncope) during physical exertion.
When the stage of decompensation sets in (right ventricular failure develops), signs of systemic venous congestion appear: acrocyanosis, enlargement of the liver and spleen (hepatosplenomegaly), jugular venous distension, and prominent peripheral edema, up to anasarca.
Diagnostics
On physical examination, one can notice a "heave" and abnormal pulsation in the epigastric region, indicating right ventricular enlargement. Auscultation reveals an accentuated second heart sound over the pulmonary artery. A Graham Steell murmur may also be auscultated—a diastolic murmur to the left of the sternum in the 2nd intercostal space. It occurs due to marked dilation of the pulmonary artery trunk and relative pulmonary valve regurgitation.
To confirm the diagnosis, the following are used:
- ECG: shows a rightward electrical axis (or vertical QRS axis). High R waves, flattened S waves, and inverted T waves are visible in the right precordial leads ($V_1$–$V_2$). In leads II and III, a tall, peaked P wave (P-pulmonale) forms, indicating right atrial overload.
- Chest X-ray: visualizes right ventricular enlargement and signs of pulmonary hypertension (especially in oblique projections).
- Echocardiography: helps accurately assess the dimensions of the right heart chambers and the pressure level in the pulmonary artery.
Principles of treatment
Treatment of chronic cor pulmonale aims at both eliminating the cause and supporting the heart.
The mainstay of treatment is the control of the underlying bronchopulmonary disease and prompt management of any exacerbations. Oxygen therapy plays a key role in pathogenetic treatment. Patients are indicated for continuous low-flow oxygen administration lasting 18 to 24 hours per day (using cylinders or concentrators). Long-term oxygen therapy reduces pressure in the pulmonary arterial system, significantly improves quality of life, and increases survival rates.
Briefly: answers to topical questions
What is the von Euler-Liljestrand reflex and what is its role in the pathogenesis of cor pulmonale?
The von Euler-Liljestrand reflex is the constriction of alveolar capillaries in response to acute alveolar hypoxia. In the pathogenesis of cor pulmonale, this mechanism underlies the development of precapillary pulmonary hypertension. When blood gas composition is disturbed, vasoconstriction occurs: in the early stages, it is local and aims to prevent the shunting of unoxygenated blood, redistributing blood flow to healthy areas. Subsequently, arteriolar spasm becomes generalized, which increases total vascular resistance and leads to the development of chronic cor pulmonale due to right ventricular overload and hypertrophy.
How is cor pulmonale classified by its rate (tempo) of development?
According to the rate of development, cor pulmonale is classified into three main forms.
| Morphology | Rate of development |
|---|---|
| Acute cor pulmonale | Minutes to hours |
| Subacute cor pulmonale | Weeks to months |
| Chronic cor pulmonale | Years |
Which diseases are included among the causes of bronchopulmonary cor pulmonale?
The causes of the bronchopulmonary form of cor pulmonale include chronic obstructive and restrictive lung diseases.
- COPD, including chronic obstructive bronchitis and pulmonary emphysema.
- Bronchiectasis.
- Pneumosclerosis.
- Interstitial pneumonias.
Class and exam questions
Why does chest pain occur behind the sternum in chronic cor pulmonale?
The pain is pressing in character and is associated with mechanical overstretching of the pulmonary artery trunk due to high pressure, rather than myocardial ischemia.
What is the essence of the Graham Steell murmur?
This is a diastolic murmur auscultated in the 2nd intercostal space on the left. It occurs due to relative pulmonary valve regurgitation resulting from dilation of the pulmonary artery trunk caused by hypertension.
What is P-pulmonale on an ECG?
This is a tall, peaked P wave in standard leads (II, III), indicating overload and enlargement of the right atrium.
What else to study on this topic
- Pathogenesis of alveolar hypoxia in airway obstruction
- Mechanisms of secondary polycythemia development in COPD
- Detailed ECG interpretation in right ventricular hypertrophy
- Evaluation of pulmonary hemodynamics using echocardiography
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