Claude Beck described two triads of clinical findings which he found constituted the essential components of acute and chronic cardiac tamponade. The first of these triads consisted of hypotension, an increased venous pressure, and a quiet heart. It has come to be recognized as "Beck's triad," a collection of findings most commonly produced by acute intrapericardial hemorrhage. Subsequent studies have shown that these classic findings are observed in only a minority of patients with cardiac tamponade. However, Beck deserves credit for presenting a physiologic basis for the signs of cardiac compression.