Pulse

Pulse refers to the rhythmic expansion of an artery as blood is ejected from the heart during each cardiac cycle. In a broader sense, pulse also denotes a transient, repetitive electrical or optical signal used to convey information. The term comes from the Latin pulsus, meaning beat or strike.

In clinical practice, the pulse is most often measured at superficial arteries such as the radial, carotid, brachial, or femoral arteries. Palpation or auscultation estimates heart rate, rhythm, and the presence of a pulse. Normal resting heart rate in healthy adults is typically 60 to 100 beats per minute, but this can vary with age, fitness, medications, fever, dehydration, and health status.

Pulse quality and rhythm can indicate hemodynamic status. A strong, regular pulse suggests adequate stroke volume and perfusion, while a weak or thready pulse may indicate shock or reduced blood flow. Arrhythmias produce irregular pulses; tachycardia and bradycardia refer to fast or slow pulse rates, respectively. Specific terms include pulsus paradoxus (an exaggerated drop in systolic BP during inspiration) and pulsus alternans (alternating strong and weak pulses). Pulse oximetry also estimates pulse rate noninvasively.

In other domains, a pulse is a short-lived electronic or optical signal that turns on and off rapidly, used in digital circuits (such as TTL signals), timing circuits, and communication. In physics and engineering, pulses can be laser pulses, acoustic pulses, or particle pulses, often characterized by duration, amplitude, and repetition rate.