Pericardial Effusion and Cardiac Tamponade
Pericardial Effusion
Definition
Pericardial effusion is defined as the abnormal fluid accumulation in the pericardial space, typically >50 mL.
The pericardial space is a potential anatomical space located between the parietal pericardium (outer layer) and visceral pericardium (epicardium, inner layer covering the heart).
It normally contains a small amount of serous fluid, which lubricates the heart’s movements during cardiac cycles.
Aetiology
The most common cause: idiopathic / viral pericarditis [Ref]
- Pericarditis or any other cause can also cause pericardial effusion. Important ones include TB, autoimmune conditions and uraemia.
- In fact, pericardial effusion is part of the diagnostic criteria for acute pericarditis (see this article for more details)
Acute causes of pericardial effusion:
- Penetrating / blunt cardiac trauma
- Aortic dissection with haemopericardium
- Ventricular free-wall rupture (after acute MI)
Pericardial effusion most often co-exists with acute pericarditis, as inflammation of the pericardium commonly leads to fluid accumulation in the pericardial space.
Clinical Features
Clinical features of pericardial effusion are highly variable and depend on the size, rate of accumulation, and underlying cause. [Ref]
Many effusions are asymptomatic and discovered incidentally. [Ref]
If symptomatic: [Ref]
- Chest pain
- Dyspnoea
- Features of acute pericarditis (e.g. pleuritic chest pain that worsens when lying down, pericardial friction rub etc.)
Complications
The most important complication is cardiac tamponade, which occurs when the pericardial fluid leads to increased intrapericardial pressure (see below).
Other complications:
- Recurrence
- Progression to constrictive pericarditis
- Pericardium calcification (rare)
Investigation and Diagnosis
1st line test: trans-thoracic echocardiography / point-of-care ultrasound (in emergency cases) [Ref]
- Pericardial effusion appears as an echo-free (anechoic) or hypoechoic space between the visceral and parietal pericardium
- Echo / ultrasound accurately detects the presence, size and distribution of fluid in the pericardial space
- Importantly, point-of-care ultrasound allows assessment for cardiac tamponade
Pericardiocentesis for fluid analysis is NOT routinely performed, it is reserved for cases where infection / malignancy is suspected. [Ref]
Management
Management depends on the underlying cause:
- Pericardial effusion with acute pericarditis → treat as acute pericarditis (see this article)
- Pericardial effusion secondary to specific causes → treat underlying cause
- Malignant or recurrent effusions → consider surgical options (e.g., pericardial window or pericardiotomy) to prevent reaccumulation
Pericardiocentesis is ONLY recommended to treat pericardial effusion in the presence of:
- Cardiac tamponade, or
- When there is a strong suspicion of bacterial, tuberculous, or malignant aetiology, requiring diagnostic fluid analysis.
Cardiac Tamponade
Definition
Cardiac tamponade occurs when there is increased intrapericardial pressure that exceeds cardiac filling pressure → impaired diastolic filling → reduced stroke volume
Cardiac tamponade is a clinical and hemodynamic diagnosis based on pressure and cardiac function compromise, rather than fluid volume alone.
The critical factor is the rate of fluid accumulation and the resulting intrapericardial pressure. The pericardium has limited stretchability; a rapid accumulation of even a small volume (e.g., 100-200 mL) can generate high pericardial pressure, leading to tamponade.
Conversely, slow fluid accumulation over weeks or months may allow the pericardium to gradually stretch, accommodating larger volumes (up to 1-2L) without causing tamponade.
Aetiology
Any cause of pericardial effusion (listed above) can result in cardiac tamponade.
The leading causes of cardiac tamponade are:
- Malignancy
- Inflammatory (including idiopathic and viral) pericarditis
- Iatrogenic injury (e.g. catheter ablation, PCI, cardiac surgery)
Clinical Features
Cardiac tamponade presents with a triad of:
| Component | Feature |
|---|---|
| Heart sound |
|
| Blood pressure |
|
| JVP |
|
Note that Kussmaul’s sign (paradoxical increase in JVP with inspiration; JVP is supposed to decrease with expiration) is not observed in patients with cardiac tamponade. It is classically associated with constrictive pericarditis and other conditions causing impaired right ventricular filling, but not with cardiac tamponade.
In cardiac tamponade, the JVP is elevated but does not rise further with inspiration.
Complications
Cardiac tamponade can rapidly progress to obstructive shock, causing subsequent cardiac arrest, multi-organ failure and death.
The 3 main causes of obstructive shock are:
- Cardiac tamponade
- Tension pneumothorax
- Massive pulmonary embolism
These conditions share a common mechanism of mechanical obstruction to cardiac filling or output.
Management
Perform immediate pericardiocentesis under echo guidance [Ref]
Supportive measures (e.g. fluid resuscitation, vasopressors) may be used as a bridge to definitive drainage if immediate pericardiocentesis is not feasible, but they are not substitutes for pericardial drainage.