Beck's triad includes which signs?

• A. JVD, muffled heart sounds, narrowed pulse pressure
• B. Cheyne-Stokes respiration
• C. Tracheal deviation
• D. Hyperresonant percussion

Answer: (A)

Beck's triad reflects the hemodynamic effects of cardiac tamponade, where the heart is compressed and filling is impaired. The signs are jugular venous distension, muffled heart sounds, and a narrowed pulse pressure due to hypotension. Jugular venous distension happens as blood backs up in the venous system when the heart can’t fill properly. Heart sounds become muffled because the surrounding fluid around the heart dampens sound transmission. The pulse pressure narrows because systolic pressure drops with reduced stroke volume while diastolic pressure remains relatively higher, leading to a smaller difference between them. Other signs listed point to different conditions: Cheyne-Stokes respiration is a breathing pattern seen with severe heart failure or brain injury; tracheal deviation suggests a shift due to pneumothorax or large mediastinal processes; hyperresonant percussion indicates excess air, as in pneumothorax.