From the Guidelines
Pericarditis and cardiac tamponade have distinct appearances on echocardiography, with pericarditis typically showing a small to moderate pericardial effusion and normal cardiac chamber size and function, whereas cardiac tamponade shows a moderate to large pericardial effusion with signs of hemodynamic compromise, including right atrial collapse, right ventricular diastolic collapse, and exaggerated respiratory variation in mitral and tricuspid inflow velocities 1.
Echocardiographic Findings
The key echocardiographic findings in pericarditis include:
- Small to moderate pericardial effusion
- Normal cardiac chamber size and function
- Thickened pericardium
- Fibrinous strands within the effusion In contrast, cardiac tamponade is characterized by:
- Moderate to large pericardial effusion
- Right atrial collapse during late diastole
- Right ventricular diastolic collapse
- Left ventricular pseudohypertrophy
- Dilated inferior vena cava with decreased respiratory variation
- Exaggerated respiratory variation in mitral and tricuspid inflow velocities (>25% and >40% respectively) 1.
Clinical Implications
The distinction between pericarditis and cardiac tamponade is crucial, as tamponade represents a medical emergency requiring immediate intervention (pericardiocentesis), while uncomplicated pericarditis can typically be managed medically with anti-inflammatory medications like NSAIDs or colchicine 1.
Diagnostic Approach
Echocardiography is the single most useful diagnostic tool to identify pericardial effusion and estimate its size, location, and degree of hemodynamic impact, and is used to guide pericardiocentesis with excellent safety and efficacy 1.
Management
The treatment of cardiac tamponade involves drainage of the pericardial fluid, preferably by needle pericardiocentesis, with the use of echocardiographic or fluoroscopic guidance, and should be performed without delay in unstable patients 1.
From the Research
Echocardiographic Differences
The echocardiographic differences between pericarditis and cardiac tamponade are as follows:
- Pericarditis is characterized by inflammation of the pericardium, which can be acute, sub-acute, or chronic, and may not always be associated with a significant pericardial effusion 2.
- Cardiac tamponade, on the other hand, is a life-threatening condition that occurs when there is a sudden and/or excessive accumulation of fluid in the pericardial space, restricting the filling of the cardiac chambers and causing hypotension and cardiac arrest 3.
- Echocardiographic findings that suggest cardiac tamponade include:
- Diastolic right ventricular collapse (high specificity) 4, 5
- Systolic right atrial collapse (earliest sign) 4
- Plethoric inferior vena cava with minimal respiratory variation (high sensitivity) 4, 3
- Exaggerated respiratory cycle changes in mitral and tricuspid valve in-flow velocities as a surrogate for pulsus paradoxus 4, 5
- In contrast, pericarditis may not always exhibit these echocardiographic findings, and the diagnosis is often made based on clinical presentation, electrocardiogram, and echocardiographic evidence of pericardial effusion 6, 2.
Diagnostic Utility of Echocardiography
Echocardiography is a crucial tool in diagnosing and quantifying pericardial effusions, and in the context of the clinical presentation, can help identify patients with impending tamponade or constrictive pericarditis 6, 5.
- A structured echocardiographic approach, including two-dimensional, M-mode, and Doppler echocardiographic evaluation, can assess the quantity and quality of pericardial fluid, collapse of cardiac chambers, respiratory variation of ventricular diameters, inferior vena cava collapsibility, and flow patterns in atrioventricular valves 3.
- Doppler ultrasound studies can also be useful in detecting increased respiratory variation in transvalvular blood flow velocities, which is a characteristic finding in cardiac tamponade 4, 5.