Constrictive Pericarditis: Pathophysiology Explained

Introduction

Constrictive pericarditis (CP) is a condition where the pericardium (the sac that surrounds the heart) becomes thickened, stiff, and sometimes calcified. This results in impaired filling of the heart chambers, leading to heart failure-like symptoms. Understanding its pathophysiology is crucial for accurate diagnosis and management.

Normal Pericardial Function

The pericardium normally plays a supportive role in the heart, allowing for: - Lubrication to reduce friction between the heart and surrounding structures. - Barrier function to prevent infections spreading to the heart. - Regulation of cardiac compliance by limiting excessive cardiac dilation in acute situations.

Pathophysiology of Constrictive Pericarditis

1. Pericardial Thickening and Fibrosis

• Chronic inflammation (due to infections, surgery, trauma, or idiopathic causes) leads to fibrosis and sometimes calcium deposition.
• The pericardium loses its flexibility and becomes a rigid shell around the heart.

2. Ventricular Interdependence

• Normally, changes in one ventricle’s filling do not drastically affect the other.
• In CP, the thickened pericardium prevents normal transmission of pressure changes, leading to a phenomenon where filling of one ventricle affects the other abnormally (ventricular interdependence).

3. Impaired Diastolic Filling

• The heart’s ability to expand during diastole (filling phase) is severely limited.
• Early filling is rapid but stops abruptly due to the rigid pericardium (“square root sign” on hemodynamic pressure tracings).

4. Equalization of Diastolic Pressures

• In a normal heart, the pressure difference between the ventricles and atria allows for efficient blood flow.
• In CP, diastolic pressures in all heart chambers become nearly identical due to the external compression-like effect.

5. Increased Systemic Venous Pressure

• Because the right heart cannot expand adequately, blood backs up into the systemic circulation, leading to:
  • Jugular venous distension (elevated neck veins)
  • Hepatic congestion (leading to liver dysfunction and ascites)
  • Peripheral edema (swelling in legs)

Hemodynamic Signs Typical for Constrictive Pericarditis

• Kussmaul’s sign: Jugular vein distension that worsens with inspiration (opposite of normal physiology).
• Pericardial knock: An early diastolic heart sound from abrupt cessation of ventricular filling.

Conclusion

Constrictive pericarditis is a severe condition where pericardial fibrosis restricts normal heart function. This leads to abnormal ventricular interactions, impaired filling, and systemic congestion. Early recognition is critical, as surgical pericardiectomy can significantly improve outcomes in select cases.

Source recommendations

1. 2022 AHA/ACC Guideline for the Diagnosis and Management of Pericardial Diseases

1. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001106
2. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Pericardial-Diseases-Guidelines-on-the-Diagnosis-and-Management-of
3. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001193
4. https://www.acc.org/education-and-meetings/image-and-slide-gallery/media-detail?id=aa19ae213ed945c090a0d8c9aa17f9cd
5. https://www.escardio.org/static-file/Escardio/Guidelines/Documents/ehaa612.pdf

2. 2021 ESC Guidelines on Pericardial Diseases

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Pericardial-Diseases-Guidelines-on-the-Diagnosis-and-Management-of
2. https://pubmed.ncbi.nlm.nih.gov/26320112/
3. https://www.escardio.org/Working-groups/Working-Group-on-Myocardial-and-Pericardial-Diseases
4. https://academic.oup.com/eurheartj/article/42/16/1554/6212698
5. https://pubmed.ncbi.nlm.nih.gov/33825853/