Beck's triad is well known to many physicians, but here's some simple things you may not have known.
Beck actually described two triads, one for acute and one for chronic tamponade. The triad for chronic tamponade consists of increased CVP (JVD), ascites, and a small quiet heart (muffled heart sounds). The triad for acute tamponade consists of JVD hypotension, and muffled heart sounds.
Almost 90% of patients have at least 1 of the signs, but only one-third have all 3. Furthermore, it appears that the simultaneous occurrence of all 3 signs is a very late manifestation of tamponade, usually preceding cardiac arrest.
References
Harper RJ. Pericardiocentesis. In Clinical Procedures in Emergency Medicine, 5th ed. Roberts JR, Hedges JR, et al. eds. Saunders, Philadelphia, 2010.
