Beck's triad (cardiology)

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 signs are low arterial blood pressure, distended neck veins, and distant, muffled heart sounds.

Narrowing pulse pressure might also be observed. The concept was developed by Claude Beck, a resident and later Professor of Cardiovascular Surgery at Case Western Reserve University.

Physiology

The fall in arterial blood pressure results from pericardial fluid accumulation to a degree that it impairs ventricular stretch, thus reducing stroke volume , a major determinant 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 in 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.

Clinical use

Although the full triad is present only in a minority of cases of acute cardiac tamponade, presence of the triad is considered pathognomonic for the condition.

External links

• Beck's sign at Who Named It?