<P> Claudius Galen was perhaps the first physiologist to describe the pulse . The pulse is an expedient tactile method of determination of systolic blood pressure to a trained observer . Diastolic blood pressure is non-palpable and unobservable by tactile methods, occurring between heartbeats . </P> <P> Pressure waves generated by the heart in systole move the arterial walls . Forward movement of blood occurs when the boundaries are pliable and compliant . These properties form enough to create a palpable pressure wave . </P> <P> The heart rate may be greater or lesser than the pulse rate depending upon physiologic demand . In this case, the heart rate is determined by auscultation or audible sounds at the heart apex, in which case it is not the pulse . The pulse deficit (difference between heart beats and pulsations at the periphery) is determined by simultaneous palpation at the radial artery and auscultation at the PMI, near the heart apex . It may be present in case of premature beats or atrial fibrillation . </P> <P> Pulse velocity, pulse deficits and much more physiologic data are readily and simplistically visualized by the use of one or more arterial catheters connected to a transducer and oscilloscope . This invasive technique has been commonly used in intensive care since the 1970s . </P>

How many types of pulses in human body