Searching for pulsus paradoxus and correlates in cardiac tamponade.

Pulsus paradoxus (PP) is a sign of great diagnostic value in cardiac tamponade. The clinical detection of PP is sometimes nebulous, especially during haemopericardium due to aortic dissection and aortic valve regurgitation, or when large atrial septal defects coexist. The Doppler echocardiographic phenomenon of flow velocity paradox along the great arteries, frequently heralds the appearance of a palpable PP. In cases of tamponade with atrial fibrillation, pulse oximetry is a rational approach for detecting the presence of PP.