Constrictive Pericarditis

Prepared and reviewed by the PrepElephant Academic Review Team

First published 8 Oct 2026 · Spot an error?

Reference basis: Braunwald's Heart Disease; Hurst's The Heart; Harrison's Principles of Internal Medicine

On this page

Direct answer
What you must remember
Separating constriction from restriction at the bedside
Where the examiner builds the distractors
Frequently asked questions
Related topics

Direct answer

Constrictive pericarditis is a fibrotic or calcified pericardium that encases the heart and restricts diastolic filling, producing a raised venous pressure, a Kussmaul sign and a diastolic pericardial knock. Tuberculosis is a leading cause in India, and the condition can follow cardiac surgery, mediastinal radiotherapy or viral infection. Pericardiectomy is the definitive treatment, while diuretics control congestion in the meantime.

What you must remember

Kussmaul sign: the jugular venous pressure rises on inspiration instead of falling; it also occurs in restrictive cardiomyopathy and right ventricular infarction.
Pericardial knock: a high-pitched early diastolic sound soon after S2, produced when a rigid pericardium abruptly halts ventricular filling.
Square-root sign: a dip-and-plateau pattern on the right ventricular pressure tracing, reflecting the sudden end of early filling.
Equalisation of pressures: right atrial, right ventricular end-diastolic, pulmonary artery diastolic and wedge pressures are roughly equal, usually within 5 mmHg.
Imaging: CT or MRI shows pericardial thickening, commonly quoted above 4 mm, and calcification is typical in tuberculous disease.
Echo: septal bounce, exaggerated respiratory variation in ventricular filling and a plethoric inferior vena cava.
Treatment: pericardiectomy, antitubercular therapy when tuberculosis is the cause, and diuretics for congestion used with care.

Separating constriction from restriction at the bedside

A 45-year-old man with a tuberculous pleural effusion treated years ago presents with ascites, leg swelling and a jugular pressure that rises when he breathes in. The ECG shows low voltage and an atrial rhythm.

Name the differential: The differential is restrictive cardiomyopathy, and the stakes are high, because pericardiectomy can cure constriction while restrictive disease carries a worse prognosis.
Listen for the knock: A pericardial knock points toward constriction, although it is not always audible, so the echo and Doppler work-up separates the two.
Read the echo: In constriction the septum moves toward the left ventricle in inspiration and mitral inflow varies more with breathing. Annular velocities are preserved, particularly at the septum, while restriction shows reduced annular velocities.
Confirm with cross-sectional imaging: Cardiac MRI or CT shows pericardial thickening or calcification, which is the most direct proof.
Exclude the mimic: Amyloid is the mimic to remember, and a low voltage ECG with thick walls and a sparkling myocardium suggests infiltration, with treatment and prognosis that differ completely from constriction.

Where the examiner builds the distractors

Most distractors here revolve around one sign and one question of cure.

Trap: choosing constriction for any raised JVP Correct: the Kussmaul sign also occurs in restrictive cardiomyopathy, right ventricular infarction and severe right heart failure, so context breaks the tie, with constriction following tuberculosis, cardiac surgery or radiotherapy.
Trap: relying on the pericardial knock alone Correct: it is classic for constriction but not always audible, so auscultation alone will miss many cases.
Trap: choosing a diuretic regimen as the best long-term option in a young patient Correct: constriction can be cured by pericardiectomy in selected patients, unlike most restrictive myopathies.

Frequently asked questions

What is the Kussmaul sign?

The Kussmaul sign is a paradoxical rise in jugular venous pressure during inspiration, instead of the usual fall. It is seen in constrictive pericarditis and restrictive cardiomyopathy, and also in right ventricular infarction.

What is the pericardial knock?

A pericardial knock is a high-pitched early diastolic sound heard soon after S2, produced when a stiff pericardium abruptly halts ventricular filling. It is characteristic of constrictive pericarditis, but it is not always audible, so imaging is needed.

How does constrictive pericarditis differ from restrictive cardiomyopathy on echo?

Constrictive pericarditis shows septal bounce, exaggerated respiratory variation in mitral inflow and preserved or increased mitral annular velocities. Restrictive cardiomyopathy shows reduced annular velocities with thick walls, while the pericardium itself is normal.

What is the square-root sign?

The square-root sign is a dip-and-plateau pattern on the right ventricular pressure tracing, reflecting an abrupt halt in early diastolic filling by a stiff pericardium. It is one of the classic invasive haemodynamic signs of constriction.

What is the definitive treatment for constrictive pericarditis?

Pericardiectomy is the definitive treatment, removing the constricting fibrous or calcified pericardium and restoring haemodynamics in selected patients. Diuretics and antitubercular therapy address symptoms and cause in the meantime.