Pericardial Effusion and Cardiac Tamponade

Risk factors

• Pericarditis of any cause (viral, idiopathic, uremic, autoimmune, TB)
• Malignancy (lung, breast, lymphoma, melanoma — leading cause of large effusions)
• Iatrogenic: cardiac surgery, catheter ablation, central line placement, pacemaker lead perforation
• Trauma (penetrating or blunt chest)
• Aortic dissection rupture into pericardium
• Myocardial rupture post-MI (free-wall rupture, days 3-7)
• Hypothyroidism (myxedema) — large chronic effusion, usually no tamponade
• Hemorrhage from anticoagulation

Pathophysiology

Pericardial pressure normally near 0 mmHg. As fluid accumulates, pressure rises along the pericardial compliance curve — initially flat, then steep once pericardium is at maximal stretch. Once intrapericardial pressure equals right atrial and ventricular diastolic pressures, chamber collapse begins, equalizing pressures across all four chambers and dropping stroke volume. Pulsus paradoxus reflects exaggerated ventricular interdependence: inspiration increases RV filling, and because total pericardial volume is fixed, the septum bows leftward, reducing LV filling and stroke volume so systolic BP falls >10 mmHg with inspiration.

Clinical presentation

Differential diagnosis

• Tension pneumothorax — Hypotension and distended JVP with unilateral absent breath sounds, hyperresonance, and tracheal deviation; clinical diagnosis — immediate needle decompression (adults: 4th/5th intercostal space just anterior to the midaxillary line; children: 2nd intercostal space midclavicular line) followed by chest tube
• Right ventricular MI — Inferior STEMI with V4R ST elevation, hypotension, clear lungs, preload-dependent; treat with IV fluids
• Massive PE — Acute right heart failure, hypoxia, RV strain on echo, no pericardial fluid
• Constrictive pericarditis — Chronic right HF with Kussmaul sign and pericardial knock; thickened/calcified pericardium without large effusion
• Cardiogenic shock — LV dysfunction primary; no chamber collapse, no significant effusion on echo
• Hypovolemic shock — Flat JVP and low filling pressures throughout; responds to volume

Diagnostic workup

Diagnostic algorithm

flowchart TD
  A[Pericardial effusion suspected<br/>dyspnea, JVD, hypotension] --> B[Bedside echo]
  B --> C{Hemodynamic compromise?<br/>Chamber collapse?<br/>Pulsus paradoxus?}
  C -->|Yes| K{"Hemopericardium from aortic dissection,<br/>free-wall rupture, or<br/>penetrating trauma?"}
  K -->|Yes| L["Emergency surgery<br/>(sternotomy or thoracotomy)"]
  K -->|No| D[Urgent echo-guided<br/>pericardiocentesis]
  C -->|No, small/moderate| E[Treat underlying cause<br/>Serial echo]
  C -->|No, large| F[Consider elective drainage<br/>if symptomatic]
  D --> G[Fluid analysis:<br/>cytology, AFB, culture,<br/>ADA, cell count]
  G --> H{Cause identified?}
  H -->|Recurrent / loculated /<br/>hemorrhagic| I[Pericardial window<br/>or pericardiectomy]
  H -->|Treatable| J[Etiology-specific care]

Treatment

Complications

• Cardiac arrest from progressive tamponade
• Recurrence of effusion (especially malignant or uremic)
• Constrictive pericarditis (post-inflammatory or post-surgical)
• Pericardiocentesis complications: ventricular puncture, coronary laceration, pneumothorax, arrhythmia
• Decompression injury — acute pulmonary edema after rapid drainage of large effusion (rare)

PANCE pearls

• Pulsus paradoxus is also seen in severe asthma, COPD, and massive PE — not specific to tamponade.
• Electrical alternans plus low-voltage ECG suggests a large effusion with swinging heart.
• AVOID intubation with positive-pressure ventilation prior to drainage if possible — preload drops and patient may arrest.
• Rate of accumulation matters more than total volume: 100 mL acute hemopericardium can tamponade.
• Hypothyroid effusions are typically large, chronic, and rarely cause tamponade; treat the hypothyroidism.

References

• ESC 2025 — 2025 ESC Guidelines for the management of myocarditis and pericarditis (Schulz-Menger J et al., Eur Heart J 2025;46:3952-4041)
• ASE 2013 — American Society of Echocardiography Guidelines on Pericardial Disease (Klein et al., J Am Soc Echocardiogr 2013)
• Nat Rev Dis Primers 2023 — Cardiac tamponade (Adler Y, Ristić AD, Imazio M, et al., Nat Rev Dis Primers 2023;9:36)