Beck's triad is classically associated with which condition?

• A. Tension pneumothorax
• B. Pulmonary embolism
• C. Myocardial infarction
• D. Cardiac tamponade

Answer: (D)

Beck's triad points to cardiac tamponade, where fluid in the pericardial sac raises the pressure around the heart and prevents normal filling during diastole. When filling is impaired, the heart can't eject effectively, causing a drop in blood pressure (hypotension). The restricted filling also backs up blood into the venous system, leading to neck vein distention. The fluid around the heart also muffles sounds, giving muffled or distant heart tones. Put together, this triad is a classic clue to tamponade. Other conditions can mimic parts of the picture (for example, tension pneumothorax can cause hypotension and JVD), but the combination of hypotension, JVD, and muffled heart sounds most specifically points to tamponade.