[5] 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.

The pulse may be further indirectly observed under light absorbances of varying wavelengths with assigned and inexpensively reproduced mathematical ratios.

Applied capture of variances of light signal from the blood component hemoglobin under oxygenated vs. deoxygenated conditions allows the technology of pulse oximetry.

It can be observed by simultaneous palpation at the radial artery and auscultation using a stethoscope at the PMI, near the heart apex, for example.

Pulse deficit has been found to be significant in the context of premature ventricular contraction[citation needed] and atrial fibrillation.

It may be due to low peripheral resistance (as seen in fever, anemia, thyrotoxicosis, hyperkinetic heart syndrome [de], A-V fistula, Paget's disease, beriberi, liver cirrhosis), increased cardiac output, increased stroke volume (as seen in anxiety, exercise, complete heart block, aortic regurgitation), decreased distensibility of arterial system (as seen in atherosclerosis, hypertension and coarctation of aorta).

A low tension pulse (pulsus mollis), the vessel is soft or impalpable between beats.

A slow rising and slowly falling pulse (pulsus tardus) is seen in aortic stenosis.

The first person to measure the heart beat was Herophilus of Alexandria, Egypt (c. 335–280 BC) who designed a water clock to time the pulse.

[16] Rumi has mentioned in a poem that "The wise physician measured the patient's pulse and became aware of his condition."

[17] The first person to accurately measure the pulse rate was Santorio Santorii who invented the pulsilogium, a form of pendulum which was later studied by Galileo Galilei.