A 50 year old man has a stab wound to his left anterior chest at the level of the 4th ICS. He has a BP 80mmHg, pulse=130bpm. His neck veins are dilated and his heart sounds are faint. His trachea is central. What is the most appropriate diagnosis?

The key is A. Cardiac tamponade. [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].