Cardiac Tamponade Workup

Updated: Nov 28, 2018
  • Author: Chakri Yarlagadda, MD, FACC, FSCAI, FASNC, CCDS; Chief Editor: Terrence X O'Brien, MD, MS, FACC  more...
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Approach Considerations

As previously stated, prompt diagnosis is key to reducing the mortality risk for patients with cardiac tamponade. Although cardiac tamponade is a clinical diagnosis, further assessment of the patient’s condition and diagnosis of the underlying cause of the tamponade can be obtained through lab studies, imaging studies, electrocardiography, and echocardiography.

Echocardiography, for example, can be used to visualize ventricular and atrial compression abnormalities as blood cycles through the heart, while lab studies can demonstrate signs of myocardial infarction, cardiac trauma, and infectious disease.

In July 2014, the European Society of Cardiology (ESC) Working Group on Myocardial and Pericardial Diseases released a stepwise scoring system for treating patients with cardiac tamponade. The system is used to identify patients who need immediate pericardiocentesis and patients who can safely be transferred to a specialized institution. [17, 18]

According to the guidelines, patients with suspected cardiac tamponade should undergo echocardiography without delay. After diagnosis, patients are scored according to disease etiology, clinical presentation, and imaging findings. A score of 6 or more requires the patient to undergo immediate pericardial drainage. A lower score indicates that drainage can be postponed for up to 12 to 48 hours. [17, 18]


Imaging Studies

Chest radiography

Chest radiography findings may show cardiomegaly, a water bottle–shaped heart, pericardial calcifications, or evidence of chest wall trauma. (See the image below.)

This anteroposterior-view chest radiograph shows a This anteroposterior-view chest radiograph shows a massive, bottle-shaped heart and conspicuous absence of pulmonary vascular congestion. Reproduced with permission from Chest, 1996: 109:825.

A bowed catheter sign on chest radiography in children after central venous catheter insertion may be suggestive of tamponade. [19]

CT scanning

Gold et al reported compression of the coronary sinus as observed through CT scanning as an earlier marker for cardiac tamponade in 46% of patients. [20]


Although echocardiography provides useful information, cardiac tamponade is a clinical diagnosis. The following may be observed with 2-dimensional (2-D) echocardiography:

  • An echo-free space posterior and anterior to the left ventricle and behind the left atrium - After cardiac surgery, a localized, posterior fluid collection without significant anterior effusion may occur and may readily compromise cardiac output

  • Early diastolic collapse of the right ventricular free wall (see the images below)

    Early diastolic collapse of right ventricular free Early diastolic collapse of right ventricular free wall (subcostal view).
    Early diastolic collapse of right ventricular free Early diastolic collapse of right ventricular free wall (parasternal short-axis view at aortic valve).
  • Late diastolic compression/collapse of the right atrium (see the image below)

    Late diastolic collapse of right atrium (subcostal Late diastolic collapse of right atrium (subcostal view).
  • Swinging of the heart in the pericardial sac

  • LV pseudohypertrophy

  • Inferior vena cava plethora with minimal or no collapse with inspiration (see the image below)

    Dilated inferior vena cava. Dilated inferior vena cava.
  • A greater than 40% relative inspiratory augmentation of blood flow across the tricuspid valve

  • A greater than 25% relative decrease in inspiratory flow across the mitral valve

Conditions that may simulate pericardial effusion on 2-D echocardiography include the following:

  • A large left pleural effusion

  • Any tumor surrounding the heart

  • Mitral annular calcification

  • A descending thoracic aorta

  • A catheter in the right ventricle

  • An enlarged left atrium

  • An annular subvalvular LV aneurysm

  • A bronchogenic cyst


Laboratory Studies

The following studies aid in the assessment of patients with cardiac tamponade:

  • Creatine kinase and isoenzymes - levels are elevated in patients with myocardial infarction and cardiac trauma

  • Renal profile and complete blood count (CBC) with differential - These tests are useful in the diagnosis of uremia and certain infectious diseases associated with pericarditis

  • Coagulation panel - The prothrombin time and activated partial thromboplastin time are useful for determining bleeding risk during interventions, such as pericardial drainage and/or the placement of pericardial windows

  • Antinuclear antibody assay, erythrocyte sedimentation rate, and rheumatoid factor - Although nonspecific, results from these tests may give clues to a connective tissue disease predisposing to the development of pericardial effusion.

  • HIV testing - Approximately 24% of all pericardial effusions are reported to be associated with HIV infection

  • Purified protein derivative testing - This is used to diagnose tuberculosis, which is an important and not uncommon cause of pericardial effusion and tamponade.



With a 12-lead electrocardiogram (see the image below), the following findings suggest, but are not diagnostic for, pericardial tamponade:

  • Sinus tachycardia

  • Low-voltage QRS complexes

  • Electrical alternans - Also observed during supraventricular and ventricular tachycardia

  • PR segment depression

    A 12-lead electrocardiogram showing sinus tachycar A 12-lead electrocardiogram showing sinus tachycardia with electrical alternans. Reproduced with permission from Chest, 1996; 109:825.

Electrical alternans

Alternation of QRS complexes, usually in a 2:1 ratio, on electrocardiographic findings is called electrical alternans. It is caused by movement of the heart in the pericardial space. Electrical alternans is also observed in patients with myocardial ischemia, acute pulmonary embolism, and tachyarrhythmias.


Pulse Oximetry

Respiratory variability in pulse-oximetry waveform is noted in patients with pulsus paradoxus. In a small group of patients with tamponade, Stone et al noted increased respiratory variability in pulse-oximetry waveform in all patients. [21] This finding should raise the suspicion for hemodynamic compromise. In patients with atrial fibrillation, pulse-oximetry may aid in detecting the presence of pulsus paradoxus.


Swan-Ganz Catheterization

Before or after insertion of the Swan-Ganz catheter, the system must be zeroed after positioning the transducer at the midpoint of the left atrium. Then calibrate the monitoring system. Prior to insertion, test the balloon and flush all of the ports. Then insert the catheter into one of the major veins.

At a depth of 20 cm, inflate the balloon and slowly advance the catheter, while continuously monitoring the pressure from the distal lumen. Always deflate the balloon before withdrawing the Swan-Ganz catheter. The waveforms help to indicate the position of the catheter tip if fluoroscopy is not readily accessible.

At approximately the 40-50 cm mark, the wedge pressure is usually recorded. Secure the catheter position, and obtain a chest radiograph to confirm the position.

In tamponade, near equalization (within 5 mm Hg) of the right atrial, right ventricular diastolic, pulmonary arterial diastolic, and pulmonary capillary wedge pressure (reflecting left atrial pressure) occurs. The right atrial pressure tracings display a prominent systolic x descent and abolished systolic y descent.

Boltwood et al described the diastolic equalization of pulmonary capillary and right atrial pressures as predominantly inspiratory; this is known as the inspiratory traction sign. [22] It results from inspiratory traction of the taut pericardium by the diaphragm.


Histologic Findings

Occasionally, a pericardial biopsy is performed when the etiology of the pericardial effusion that caused the tamponade is unclear. This is especially useful in cases of tuberculous pericardial effusions, because cultures of the pericardial fluid in these cases rarely yield a positive result for mycobacteria. However, granulomas seen on pericardial biopsy specimens are often seen in patients with tuberculous pericarditis.

In general, cytopathologic findings from pericardial fluid and histologic findings from pericardial biopsy specimens depend on the underlying pathology. Cytologic examination identifies the etiopathologic cause of tamponade in about 75% of cases; it is particulalry useful for identifying malignancy-associated effusions. [23]