Cardiac Tamponade

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In 1935, Claude S. Beck remarked (boasted?) that “Osler not infrequently lamented his failure to recognize…” and Laënnec had “problems in diagnosis” of “lesion[s] of the pericardium” [1]. The famous Beck’s triad that he proposed: muffled heart sounds, elevated JVP, and hypotension, he called the “acute cardiac compression triad”. We might refer to this pathology today as “surgical” or acute tamponade, typically the result of rapid fluid accumulation after trauma or aortic dissection.

It turns out Beck’s triad is not often present in “medical” or subacute tamponade, where the fluid accumulates in a manner that allows for gradual distention of the pericardial space. In this setting, other exam findings more predictive of tamponade.

The JAMA article’s author’s and Steven McGee’s literature reviews agree that tachycardia, elevated JVP, and pulsus paradoxus are the most useful signs of tamponade [2,3].

Tachycardia is present in 81-100% of cases [3] with a pooled sensitivity of 77% [2], while elevated JVP was present 100% of the time [3] with 76% pooled sensitivity [2].

Pulsus paradoxus

Pulsus paradoxus (PP), if defined as >10 mmHg, is present in 98% of cases of cardiac tamponade [3] and has a pooled sensitivity of 82% [2].

In the one study identified that evaluated the discriminatory ability of PP for cardiac tamponande, E.I. Curtis et al. found that if > 12 mmHg, PP had a +LR 5.9 and -LR 0.03 (reference was a ≥ 20% increase in cardiac output after pericardiocentesis) [4]. This also suggests a PP predicts who will respond to pericardiocentesis.

ECG and CXR [2]

Though widely taught, ECG findings are not helpful. Low QRS voltage has a pooled sensitivity of only 42% and electrical alternans had a sensitivity of 16%-21%.

Cardiomegaly on CXR on the other hand may be helpful with a pooled sensitivity of 89%.

Echocardiography

Echo is actually sometimes considered a reference standard for diagnosis of tamponade. However, it seems that the developed criteria are overly sensitive and can identify patients without hemodynamic compromise.

For example, in one study of 50 medical patients, 98% had an SBP >100 and 58% had an adequate cardiac output (CI ≥ 2.3 L/min/m2) [5]. This, however, should be seen as an advantage, identifying early tamponade before the final volume increments lead to critical cardiac compression (the “last drop” phenomenom) [6], and avoiding any “embarrassment”.

The US findings of tamponade physiology are described elsewhere.

Summary

In summary, a patient suspected to have tamponade, should present with dyspnea, will likely have tachycardia, elevated JVP and PP >10-12 mmHg on exam, and may have cardiomegaly on CXR. A formal echocardiogram should be ordered to evaluate but a cardiac ultrasound at the point of care may aid in expediting the diagnosis.

  1. CS Beck. Two Cardiac Compression Triads. JAMA. 1935;104(9):714-716.
  2. Roy CL, et al. Does this patient with a pericardial effusion have cardiac tamponade? JAMA. 2007 Apr 25;297(16):1810-8.
  3. Stephen McGee’s Evidenced Based Physical Diagnosis, 4th ed, Elsevier, Philadelphia, PA, 2018.
  4. EI Curtiss, et al. Pulsus paradoxus: definition and relation to the severity of cardiac tamponade. Am Heart J. 1988 Feb;115(2):391-8.
  5. MJ Levine. et al. Implications of echocardiographically assisted diagnosis of pericardial tamponade in contemporary medical patients: detection before hemodynamic embarrassment. J Am Coll Cardiol. 1991 Jan;17(1):59-65.
  6. DH Spodick DH. Acute cardiac tamponade. N Engl J Med. 2003 Aug 14;349(7):684-90.