Cardiac Tamponade: Overview 

Definition: 
Cardiac tamponade is a life-threatening condition in which fluid accumulates in the pericardial space, leading to increased intra-pericardial pressure, impaired ventricular filling, and reduced cardiac output. 

Aetiology (Causes): 

Acute causes: 
Trauma (blunt or penetrating) 
Acute pericarditis 
Aortic dissection 
Myocardial rupture post-MI 
Iatrogenic (post-cardiac surgery or central line placement) 

Subacute/Chronic causes: 
Malignancy (lung, breast, lymphoma) 
Uraemia 
Hypothyroidism 
Connective tissue disease (SLE) 

Pathophysiology 
Fluid accumulation → ↑ intra-pericardial pressure. 
Ventricular filling is impaired during diastole, especially the right side (because it is thinner walled). 
Reduced stroke volume → hypotension and compensatory tachycardia. 
Pulsus paradoxus occurs: ≥10 mmHg drop in systolic BP during inspiration due to exaggerated interventricular dependence. 
If untreated, can progress to shock and death. 

Clinical Features 
Beck’s triad (classic but not always present): 
Hypotension – low cardiac output 
Jugular venous distension (JVD) – due to impaired venous return 
Muffled heart sounds – fluid dampens sound transmission 

Other features: 
Tachycardia 
Pulsus paradoxus (>10 mmHg drop in SBP during inspiration) 
Dyspnoea, tachypnoea 
Weak peripheral pulses 
Cold, clammy extremities in severe cases 

Investigations 

Electrocardiogram (ECG): 
Low voltage QRS 
Electrical alternans (R waves different heights – demonstrating the swinging of the heart in fluid) 

Chest X-ray: 
Enlarged, “water bottle” shaped heart (if chronic accumulation) 

Echocardiography (diagnostic test of choice): 
Pericardial effusion 
Right atrial or right ventricular diastolic collapse 
Plethoric inferior vena cava (IVC) with minimal respiratory variation 

Management 

Emergency treatment: 

Pericardiocentesis: aspiration of pericardial fluid under echocardiographic or fluoroscopic guidance. 
Volume resuscitation with IV fluids to maintain preload until definitive treatment. 
Oxygen and monitoring in unstable patients. 

Definitive treatment: 
Address underlying cause (infection, malignancy, trauma). 
Surgical options: pericardial window or pericardiectomy for recurrent or loculated effusions. 

Key Points:

Beck’s triad is classic but only present in ~50% of cases. 
Pulsus paradoxus is a sensitive clinical sign. 
Echocardiography is diagnostic and guides pericardiocentesis. 
Rapid recognition and intervention are life-saving