What is a possible reason for pulse deficit?

A pulse deficit occurs when the heart rate measured at the wrist (radial pulse) is lower than the heart rate measured by auscultation (listening with a stethoscope). A possible reason for pulse deficit is atrial fibrillation, a common heart arrhythmia. In atrial fibrillation, the heart's upper chambers (atria) beat irregularly and rapidly, while the lower chambers (ventricles) beat in response to the atrial contractions. This irregular heart rate can make it difficult for the heart to fill completely with blood between beats, leading to a pulse deficit.