Which of the following is NOT a sign of cardiac tamponade?

In the context of cardiac tamponade, the presence of muffled heart sounds, increased heart rate, and jugular vein distention are all hallmark signs of this condition.

Muffled heart sounds occur due to the fluid accumulation around the heart, which dampens the sounds of the heart beating through the chest wall. Increased heart rate is a compensatory response to the decreased stroke volume caused by the pressure on the heart, as the body attempts to maintain adequate cardiac output. Jugular vein distention results from elevated central venous pressure, as the fluid in the pericardial sac compresses the heart and impedes its ability to fill properly.

In contrast, high blood pressure is not typically associated with cardiac tamponade. In fact, patients often present with hypotension due to impaired cardiac output resulting from the compromised filling of the heart. This phenomenon illustrates the hemodynamic instability that characterizes cardiac tamponade, further confirming that high blood pressure does not align with the classic presentation of this condition.