What is Beck’s Triad in Cardiology?

Beck’s Triad  in Cardiology

Beck’s Triad of the heart includes three medical signs that indicate cardiac tamponade. Cardiac tamponade is medical emergency in which fluid accumulates around the heart and decreases the ability of the heart to pump blood. The result is the triad of low arterial blood pressure, jugular venous distention, and  muffled heart sounds. In cardiac tamponade a narrow pulse pressure is regularly observed. The cardiologist, Claude Beck, who was a Professor of Cardiovascular Surgery first identified the triad of medical signs which was later termed “Beck’s Triad.”

Beck’s Triad (in basic terms):

1. Distended Neck Veins;

2. Muffled Heart Sounds;

3.  Hypotension.

 The reasons for the cardiac causes of Beck’s Triad include the following:

1. Physiological fall in arterial blood pressure, which is the  results of pericardial fluid accumulation within the heart that acts in order to impair the ventricular stretch, thus reducing stroke volume and cardiac output. These two factors of Beck’s Triad are two major determinants of systolic blood pressure.

 2. The rising central venous pressure which is evidenced by distended jugular veins while in a non-supine position. This is caused by reduced diastolic filling of the right ventricle, due to the  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.

 3. The suppressed heart sounds occur due to the muffling effects of the sounds passing through the fluid surrounding the heart.

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