Pulsus paradoxus is most commonly associated with which condition?

• A. Cardiac tamponade
• B. Tension pneumothorax
• C. Pleural effusion
• D. Pericardial effusion without tamponade

Answer: (A)

Pulsus paradoxus is an exaggerated drop in systolic blood pressure during inspiration, reflecting an inspiratory decrease in left ventricular stroke volume when venous return to the right heart increases but the heart is constrained. This dynamic is most pronounced in cardiac tamponade, where the pericardial fluid restricts filling and small inspiratory changes cause a large fall in systolic pressure. In tamponade you often see this sign alongside other clues of impaired filling. Tension pneumothorax can cause hypotension and breathing-related changes, but pulsus paradoxus is most characteristically linked to tamponade. Pericardial effusion without tamponade or pleural effusion do not typically produce a significant pulsus paradoxus because the heart filling isn’t sufficiently restricted.