top of page
Search

Pericarditis vs Tamponade vs Constriction

TL;DR

Cardio: Pericarditis vs. Tamponade vs. Constriction is a classic MRCP Part 1 comparison that tests clinical reasoning across inflammation, acute compression, and chronic restriction. Pericarditis presents with pleuritic chest pain and diffuse ST elevation; tamponade causes hypotension with raised JVP and pulsus paradoxus; constrictive pericarditis leads to chronic right heart failure with Kussmaul’s sign. Recognising these patterns quickly is essential for exam success.


Why this matters

Pericardial diseases are frequently tested in MRCP Part 1, especially in “best diagnosis” or “most likely mechanism” questions. The exam expects rapid differentiation between acute inflammation (pericarditis), life-threatening compression (tamponade), and chronic restrictive physiology (constriction).

Candidates often confuse tamponade with constriction or misinterpret ECG findings. Mastering a few high-yield patterns can reliably secure marks.

Start your structured preparation with the MRCP Part 1 overview and reinforce concepts using Free MRCP MCQs.


Core sections

1. The Big Picture: Three Mechanisms

  • Pericarditis → inflammation of the pericardium

  • Tamponade → fluid accumulation causing pressure and collapse

  • Constrictive pericarditis → fibrotic, non-compliant pericardium

Understanding the mechanism explains every clinical feature.

2. High-Yield Comparison Table

Feature

Pericarditis

Cardiac Tamponade

Constrictive Pericarditis

Pathology

Inflammation

Fluid under pressure

Fibrosis/calcification

Onset

Acute

Acute/subacute

Chronic

Chest pain

Sharp, pleuritic

Usually absent

Absent

JVP

Normal or mildly ↑

Markedly ↑

↑ with Kussmaul’s sign

Blood pressure

Normal

↓ (shock)

Often normal

Pulsus paradoxus

Absent

Present

Mild/variable

Heart sounds

Pericardial rub

Muffled

Pericardial knock

ECG

Diffuse ST elevation, PR depression

Low voltage, electrical alternans

Non-specific

Key sign

Friction rub

Beck’s triad

Kussmaul’s sign

This table is one of the highest-yield summaries for MRCP Part 1.

3. Pericarditis: High-Yield Features

Clinical features:

  1. Sharp, pleuritic chest pain

  2. Worse on lying flat

  3. Relieved by sitting forward

  4. Pericardial friction rub

ECG changes:

  • Diffuse concave ST elevation

  • PR depression

Common causes:

  • Viral infection (most common)

  • Post-myocardial infarction (Dressler’s syndrome)

  • Uraemia

  • Autoimmune conditions

Exam pearl: Diffuse ST elevation across multiple leads with PR depression strongly suggests pericarditis, not myocardial infarction.

4. Cardiac Tamponade: The Emergency Diagnosis

Tamponade occurs when pericardial fluid compresses the heart, impairing ventricular filling.

Beck’s triad:

  • Hypotension

  • Raised JVP

  • Muffled heart sounds

Additional findings:

  • Tachycardia

  • Narrow pulse pressure

  • Pulsus paradoxus (>10 mmHg drop during inspiration)

ECG findings:

  • Low voltage QRS

  • Electrical alternans

Exam pearl: Hypotension + raised JVP should immediately raise suspicion of tamponade rather than heart failure.

5. Constrictive Pericarditis: Chronic Restrictive Physiology

This condition results from a rigid, scarred pericardium restricting diastolic filling.

Key features:

  • Chronic right-sided heart failure (ascites, peripheral oedema)

  • Elevated JVP

  • Kussmaul’s sign (rise in JVP on inspiration)

  • Pericardial knock

Common causes:

  • Tuberculosis (high-yield in exams)

  • Previous cardiac surgery

  • Radiation therapy

Exam pearl: Kussmaul’s sign is a hallmark of constrictive pericarditis, not tamponade.

6. Five Most Tested Subtopics

  1. ECG differentiation: pericarditis vs myocardial infarction

  2. Mechanism and significance of pulsus paradoxus

  3. Kussmaul’s sign vs tamponade physiology

  4. Causes of constrictive pericarditis (especially TB)

  5. Interpretation of Beck’s triad

7. Pathophysiology Made Simple

  • Pericarditis → inflammation → pain + ECG changes

  • Tamponade → pressure → impaired filling → shock

  • Constriction → rigidity → chronic venous congestion

Understanding this reduces memorisation burden.


Doctor preparing for MRCP Part 1 using online Qbank to study pericardial diseases and cardiovascular topics

Practical examples / mini-cases

MCQ Example:

A 52-year-old man presents with dyspnoea and hypotension. Examination reveals raised JVP and muffled heart sounds. ECG shows low voltage QRS complexes.

What is the most likely diagnosis?

A. Acute pericarditisB. Constrictive pericarditisC. Cardiac tamponadeD. Dilated cardiomyopathy

Answer: C. Cardiac tamponade

Explanation:

  • Hypotension + raised JVP suggests impaired cardiac filling

  • Muffled heart sounds complete Beck’s triad

  • Low voltage ECG supports fluid accumulation


Common pitfalls (5 bullets)

  • Mistaking diffuse ST elevation for STEMI

  • Forgetting PR depression in pericarditis

  • Confusing Kussmaul’s sign with tamponade

  • Ignoring tuberculosis as a key cause of constriction

  • Assuming Beck’s triad is always present


Practical study-tip checklist

  • Memorise the comparison table

  • Focus on pattern recognition, not isolated facts

  • Practise ECG interpretation regularly via Free MRCP MCQs

  • Use timed practice with a Start a mock test

  • Revise alongside cardiology notes (see suggested blog link)


FAQs

1. How do you differentiate pericarditis from myocardial infarction?

Pericarditis causes diffuse ST elevation and PR depression, while MI shows regional ST elevation with reciprocal changes. Pain in pericarditis improves when sitting forward.

2. What is pulsus paradoxus?

A drop in systolic blood pressure of more than 10 mmHg during inspiration, classically seen in cardiac tamponade due to impaired ventricular filling.

3. What is Kussmaul’s sign?

A rise in JVP during inspiration, seen in constrictive pericarditis and restrictive cardiomyopathy, indicating impaired right ventricular filling.

4. What causes constrictive pericarditis?

Tuberculosis is the most commonly tested cause, followed by cardiac surgery and radiation therapy.

5. What is Beck’s triad?

Hypotension, raised JVP, and muffled heart sounds—classic features of cardiac tamponade, though not always all present.


Ready to start?

Build strong cardiovascular fundamentals for MRCP Part 1 with the MRCP Part 1 overview. Practise actively using Free MRCP MCQs and simulate exam conditions with a Start a mock test.


Sources

 
 
 

Comments

bottom of page