Pulse


In medicine, a pulse represents the tactile arterial palpation of the cardiac cycle by trained fingertips. The pulse may be palpated in any place that allows an artery to be compressed near the surface of the body, such as at the neck, wrist, at the groin, behind the knee, near the ankle joint, and on foot. Pulse is equivalent to measuring the heart rate. The heart rate can also be measured by listening to the heart beat by auscultation, traditionally using a stethoscope and counting it for a minute. The radial pulse is commonly measured using three fingers. This has a reason: the finger closest to the heart is used to occlude the pulse pressure, the middle finger is used get a crude estimate of the blood pressure, and the finger most distal to the heart is used to nullify the effect of the ulnar pulse as the two arteries are connected via the palmar arches. The study of the pulse is known as sphygmology.

Physiology

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.
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.
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 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.
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.
The rate of the pulse is observed and measured by tactile or visual means on the outside of an artery and is recorded as beats per minute or BPM.
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?

Characteristics of pulse

Rate

Normal pulse rates at rest, in beats per minute :
newborn
infants
infants
children
children over 10 years
& adults, including seniors		well-trained
adult athletes
99-14989–11979-11969–12959–9939–59

The pulse rate can be used to check overall heart health and fitness level. Generally lower is better, but bradycardias can be dangerous. Symptoms of a dangerously slow heartbeat include weakness, loss of energy and fainting.

Rhythm

A normal pulse is regular in rhythm and force. An irregular pulse may be due to sinus arrhythmia, ectopic beats, atrial fibrillation, paroxysmal atrial tachycardia, atrial flutter, partial heart block etc. Intermittent dropping out of beats at pulse is called "intermittent pulse". Examples of regular intermittent pulse include pulsus bigeminus, second-degree atrioventricular block. An example of irregular intermittent pulse is atrial fibrillation.

Volume

The degree of expansion displayed by artery during diastolic and systolic state is called volume. It is also known as amplitude, expansion or size of pulse.

Hypokinetic pulse

A weak pulse signifies narrow pulse pressure. It may be due to low cardiac output, hypovolemia, valvular heart disease etc.

Hyperkinetic pulse

A bounding pulse signifies high pulse pressure. It may be due to low peripheral resistance, increased cardiac output, increased stroke volume, decreased distensibility of arterial system.
The strength of the pulse can also be reported:
Also known as compressibility of pulse. It is a rough measure of systolic blood pressure.

Tension

It corresponds to diastolic blood pressure. A low tension pulse, the vessel is soft or impalpable between beats. In high tension pulse, vessels feel rigid even between pulse beats.

Form

A form or contour of a pulse is palpatiory estimation of arteriogram. A quickly rising and quickly falling pulse is seen in aortic regurgitation. A slow rising and slowly falling pulse is seen in aortic stenosis.

Equality

Comparing pulses and different places gives valuable clinical information.
A discrepant or unequal pulse between left and right radial artery is observed in anomalous or aberrant course of artery, coarctation of aorta, aortitis, dissecting aneurysm, peripheral embolism etc. An unequal pulse between upper and lower extremities is seen in coarctation to aorta, aortitis, block at bifurcation of aorta, dissection of aorta, iatrogenic trauma and arteriosclerotic obstruction.

Condition of arterial wall

A normal artery is not palpable after flattening by digital pressure. A thick radial artery which is palpable 7.5–10 cm up the forearm is suggestive of arteriosclerosis.

Radio-femoral delay

In coarctation of aorta, femoral pulse may be significantly delayed as compared to radial pulse. The delay can also be observed in supravalvar aortic stenosis.

Patterns

Several pulse patterns can be of clinically significance. These include:
Sites can be divided into peripheral pulses and central pulses. Central pulses include the carotid, femoral, and brachial pulses.

Upper limb

Although the pulse can be felt in multiple places in the head, people should not normally hear their heartbeats within the head. This is called pulsatile tinnitus, and it can indicate several medical disorders.

Torso

The first person to accurately measure the pulse rate was Santorio Santorii who invented the pulsilogium, a form of pendulum, based on the work by Galileo Galilei. A century later another physician, de Lacroix, used the pulsilogium to test cardiac function.