Correspondence

Re: Pericardial effusion impending tamponade: a look beyond Beck’s triad

To the Editor,

We read the excellent article by Jacob et al [1] entitled “Pericardial effusion impending tamponade: a look beyond Beck’s triad” in the recent edition of The American Journal of Emergency Medicine with great interest.

Cardiac tamponade is a life-threatening condition that requires prompt and accurate diagnosis such that appropriate management can be undertaken. Jacob et al [1] discuss the diagnostic challenge in cardiac tamponade with the non- specific radiographic, electrocardiogram, and physical find- ings. The use of echocardiogram allows rapid diagnosis of cardiac tamponade and has the advantage in that it can be performed at the bedside. Nevertheless, it is limited by a dependence on operator competence and familiarity with equipment and pathology. Furthermore the ever-increasing problem of obesity can severely limit the Diagnostic ability of Ultrasound techniques. It is for these reasons that we would like to highlight the capabilities of Cross-sectional imaging. The development of multidetector computerized tomogra- phy (CT) with electrocardiogram gating allows the acquisition of cine images. Scan times are fast, and accurate diagnostic information about dynamic cardiac function can be obtained in patients with limited breath-holding ability, a problem that can limit echocardiograms. Acquired static images can also demonstrate signs that are highly suggestive of tamponade in the setting of a large pericardial effusion. These include enlargement of the superior or inferior vena cava and reflux of contrast into the inferior vena cava or azygos veins, among others [2]. The use of CTeliminates the false-positive findings with echocardiography due to surrounding pathology, such as atelectasis or Pleural effusions. Another significant advantage is the ability of CT to detect pericardial calcification, a finding highly suggestive of constrictive pericarditis, an important mimicker of tamponade [3]. The larger field of view used also

allows assessment of the thorax

The longer scan times make the role of magnetic resonance imaging (MRI) limited in the setting of cardiac tamponade. However, MRI is very sensitive in the detection of pericardial effusions, and different signal characteristics

on various sequences can provide information on the likely etiology of an effusion [4]. Similar to CT, the uses of MRI cine imaging can accurately demonstrate tamponade if the patient is stable.

The use of cross-sectional imaging is not suitable for all patients, and echocardiography should remain the first-line investigation. The requirement for the patient to lie flat for CT or MRI is an important consideration. The use of contrast and ionizing radiation in CT or the presence of a pacemaker as a contraindication to MRI is also an important factor. Nevertheless, cross-sectional imaging has an important role to play in the diagnosis of cardiac tamponade in those patients with equivocal echocardiograph results or who are poor candidates for echocardiogram.

Graeme McNeill

Department of Radiology AMNCH Tallaght, Dublin 24, Ireland

Darragh Halpenny

Department of Radiology AMNCH Tallaght, Dublin 24, Ireland

Aisling Snow

Department of Radiology AMNCH Tallaght, Dublin 24, Ireland

William C. Torreggiani

Department of Radiology AMNCH Tallaght, Dublin 24, Ireland

E-mail address: [email protected] doi:10.1016/j.ajem.2009.04.034

References

1. Jacob S, Sebastian J, Cherian P, Abraham A, John S. Pericardial effusion impending tamponade: a look beyond Beck’s triad. Am J Emerg Med 2009;27(2):216-9.
2. Killenn KL, Poletti PA, Shanmuganathan K, Mirvis SE. CT diagnosis of cardiac and pericardial injuries. Emerg Radiol 1999;6:330-44.
3. Breen JF. Imaging of the pericardium. J Thorac Imaging 2001;16:47-54.
4. Glockner JF. Imaging of pericardial disease. Magn Reson Imaging Clin N Am 2003;11:149-62.

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