Approach

Cardiac tamponade is a medical emergency that is rapidly fatal if not promptly recognised and treated. Diagnosis is based on clinical suspicion and supported by evidence of haemodynamic compromise on echocardiography.[2]

History and physical examination

Patients may be unable to provide a full medical or surgical history, particularly if they are severely haemodynamically unstable or in cardiogenic shock; however, where possible, pertinent risk factors and potential underlying causes should be elicited. These include: malignancy (including any treatments received), recent infection, recent history of cardiac surgery or intervention, end-stage renal failure, tuberculosis, hypothyroidism, and autoimmune disease.[18][27][31][35][36]​​​​​[37]​​[38]

Up to 90% of patients with cardiac tamponade will report dyspnoea. Other commonly reported symptoms include: chest pain (12% to 74%), fever (7% to 70%), abdominal pain (12% to 61%), and orthopnoea (23% to 51%).[10]​ Note that symptoms vary between patients and will also be related to the underlying cause.

In classic tamponade presenting with haemodynamic instability, signs and symptoms will be consistent with low cardiac output and stroke volume coupled with high right-sided filling pressures and increased sympathetic tone.[2]​ Typically, these are often absent in patients with low-pressure tamponade due to underlying hypovolaemia.[4]​​[6]​​​

Most patients will not present with all of the classic features of the Beck's triad (hypotension, distant heart sounds, and raised jugular venous pressure [JVP]).[10][40]​​​[41] One systematic review found that the sensitivities of hypotension and distant heart sounds were low, at 26% and 28%, respectively.[40]​ The most common physical examination findings included: tachycardia, raised JVP, and pulsus paradoxus (>10 mmHg drop in systolic blood pressure with inspiration), with pooled sensitives of 76% to 82%.​​​[40]​ Severe pulsus paradoxus can lead to a disappearance of the peripheral pulses with inspiration.

Investigations

Given the critical nature of cardiac tamponade, diagnostic investigations are narrower in scope. Echocardiography is a first-line investigation that must be performed in all patients with suspected tamponade.[4]​​[15]​​​ Imaging with cardiac computed tomography (CT) or magnetic resonance imaging (MRI) does not have a role in acute cases where life-saving intervention is required, but may be considered in more complex aetiologies. Laboratory tests may be useful in investigating underlying aetiology. Chest x-ray (CXR) and ECG are not diagnostic.

Laboratory tests

Full blood count, erythrocyte sedimentation rate, and C-reactive protein are useful in evaluating for inflammatory, infective, or anaemic causes or pericardial effusion as may be found in inflammatory pericarditis or anaemia in chronic renal failure.[15]

Biomarkers of myocardial injury are raised in cardiac trauma or myocardial infarction.

Transthoracic echocardiogram

Echocardiography is a first-line investigation in cases of suspected cardiac tamponade as it provides rapid, readily available haemodynamic data to detect tamponade physiology.[4]​​[15]​​​ Alongside evidence of pericardial effusion, findings that are diagnostic of cardiac tamponade include:[4]​​

  • Inversion of the free wall of the right atrium for more than one third of systole.[42]

  • Right ventricular (RV) diastolic collapse if the right ventricular wall is of normal compliance.​​[11][43]

  • A variation in transmitral inflow greater than 30% and/or in transtricuspid flow greater than 60% during respiration on Doppler recording (the echocardiographic demonstration of the clinical sign of pulsus paradoxus).[4]​​[15][44]

  • A variation in chamber sizes with respiration (larger RV and smaller left ventricle [LV] with inspiration).

  • Dilated inferior vena cava (IVC) and hepatic veins.

  • Reduced LV size and appearance of LV hypertrophy.

  • Septal shift (or ‘bounce’) with inspiration.

If diagnostic echocardiographic features are absent but tamponade is still clinically suspected, atypical forms of tamponade (loculated effusion, low pressure, external compression from tumour, or pleural effusion) should be considered and further investigated.

ECG

Although ECG is not diagnostic for tamponade, it may be useful in identifying pericarditis as an underlying cause.[15]​ A rhythm strip should be collected to look for beat-to-beat electrical alternans, which is a more specific sign of tamponade and is rarely seen in its absence.[5][15]​​​​ Low QRS voltage may also indicative of tamponade, but its absence does not exclude it.[15][45]

CXR

CXR has no role in the initial diagnostic work-up of cardiac tamponade as it is neither sensitive nor specific. The pericardium can hold over 200 cm³ of fluid before an enlarged silhouette is noted.[2][5]​​​​​ However, CXR may be helpful in ruling out other causes of dyspnoea and chest pain.

Cardiac CT or MRI

Cardiac CT or MRI may be considered in cases of complicated cardiac tamponade: for example, in postoperative or loculated pericardial effusions.[4]​​

Evidence of cardiac tamponade on static CT and MRI include:[4]​​

  • Compression of the anterior cardiac surface causing a 'flattened heart'.

  • Angulation/bowing of the interventricular septum (correlating with inspiratory septal bounce on echocardiography).

  • Enlarged superior vena cava and IVC.

On dynamic CT and MRI, diagnostic features of cardiac tamponade are similar to those found on echocardiography.

Cardiac catheterisation

The most specific test for the diagnosis of tamponade is demonstration of equalisation of chamber pressures; however, invasive haemodynamic monitoring is rarely necessary and is infrequently performed in patients with pure tamponade.[15]​ It is useful in differentiating tamponade from constrictive pericarditis or restrictive cardiomyopathy.

Pericardiocentesis fluid for culture and cytology

Pericardiocentesis may help differentiate the underlying cause in non-traumatic cases and is the mainstay of treatment, but may also be useful in diagnosing potential aetiology.

Use of this content is subject to our disclaimer