Beck's triad (cardiology)
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Beck's triad is a collection of three medical signs associated with acute cardiac tamponade, an emergency condition wherein fluid accumulates around the heart and impairs its ability to pump blood. The result is the triad of low arterial blood pressure, increased central venous pressure, and distant heart sounds.[1]
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[edit] Physiology
The fall in arterial blood pressure results from pericardial fluid accumulation to a degree that it impairs ventricular stretch, thus reducing stroke volume and cardiac output, two major determinants of systolic blood pressure.
The rising central venous pressure is evidenced by distended jugular veins while in a non-supine position. It is caused by reduced diastolic filling of the right ventricle, due to the outside pressure being exerted on it by the expanding pericardial sac. This results of a backup of fluid into the veins draining into the heart, most notably, the jugular veins. In severe hypovolemia, the neck veins may not be distended.
The suppressed heart sounds occur due to the muffling effects of the sounds passing through the fluid surrounding the heart.
[edit] Clinical use
Although the full triad is present only in a minority of cases of acute cardiac tamponade,[1] presence of the triad is considered pathognomonic for the condition.[2]
[edit] References
- ^ a b Sternbach G (1988). "Claude Beck: cardiac compression triads". J Emerg Med 6 (5): 417–9. doi: . PMID 3066820.
- ^ Demetriades D (1986). "Cardiac wounds. Experience with 70 patients". Ann. Surg. 203 (3): 315–7. PMID 3954485.