Beck triad is a collection of three clinical signs associated with pericardial tamponade which is due to an excessive accumulation of fluid within the pericardial sac.
The three signs are:
- low blood pressure (weak pulse or narrow pulse pressure)
- muffled heart sounds
- raised jugular venous pressure
The accumulation of fluid in the pericardial sac, particularly if it happens quickly, can result in marked increased pressure outside the heart; this subsequently reduces the ability of the ventricles to accommodate enough blood volume at the end of diastole. Based on Frank Starling's law, a decreased end-diastolic volume means weaker stroke volume and hence lower systolic blood pressure. Also, increased outside pressure reduces the end-systolic filling capacity of the atria, hence a rapid increase and higher pressure in atria leads to increased pressure in, and distension of, the jugular veins even when the patient is in an upright position. Excess fluid around the heart deadens the cardiac sounds.
History and etymology
It was first described in 1935 by an American cardiothoracic surgeon Calude Beck (1894-1971).