During the contraction of the heart, another portion of blood is pushed into the vascular system. A blow to the artery wall creates oscillations that, propagating through the vessels, gradually attenuate towards the periphery. They also received the name of pulse.
What is the pulse?
In the human body, there are three types of vessels: arteries, veins and capillaries. The ejection of blood from the heart somehow affects each of them, causing their walls to vibrate. Of course, arteries as the vessels closest to the heart are more susceptible to cardiac output. Fluctuations in their walls are well defined by palpation, and in large vessels even visible to the naked eye. That is why arterial pulse is most important for diagnosis.
Capillaries are the smallest vessels in the human body, but even the work of the heart is reflected on them. Their walls fluctuate in time with the heartbeat, but normally this can only be determined using special devices. A capillary pulse noticeable to the naked eye is a sign of pathology.
The veins are removed from the heart so much that their walls do not oscillate. The so-called venous pulse is the transmission vibrations from closely located large arteries.
Why determine the pulse?
What significance do the fluctuations of the vascular walls have for diagnosis? Why is this so important?
The pulse allows you to judge about hemodynamics, about how efficiently the heart muscle contracts , about the fullness of the vascular bed, about the rhythm of heartbeats.
With many pathological processes, the pulse changes, the characteristic of the pulse ceases to correspond to the norm. This allows us to suspect that not everything is in order in the cardiovascular system.
What parameters determine the pulse? Heart rate
- Rhythm. Normally, the heart contracts at regular intervals, which means that the pulse must be rhythmic.
- Frequency. There are as many normal pulse waves as heart beats per minute.
- Voltage. This indicator depends on the value of systolic blood pressure. The higher it is, the more difficult it is to squeeze an artery with your fingers, i.e. heart rate is high.
- Filling. Depends on the volume of blood ejected by the heart into systole.
- Magnitude. This concept combines filling and stress.
- Shape is another parameter that determines the pulse. The characteristic of the pulse in this case depends on the change in blood pressure in the vessels during systole (contraction) and diastole (relaxation) of the heart.
Rhythm disturbances
In case of disturbances in the generation or conduction of an impulse along the heart muscle, the rhythm of the contractions of the heart changes, and the pulse changes with it. Individual fluctuations in the vascular walls begin to fall out, or appear prematurely, or follow each other at irregular intervals.
What are the rhythm disturbances?
Arrhythmias with a change in the work of the sinus node (the site of the myocardium that generates impulses leading to a contraction of the heart muscle):
- Sinus tachycardia - an increase in the frequency of contractions.
- Sinus bradycardia - a decrease in the frequency of contractions.
- Sinus arrhythmia - contractions of the heart at irregular intervals.
Ectopic arrhythmias. Their occurrence becomes possible when a lesion appears in the myocardium with activity higher than that of the sinus node. In this situation, the new pacemaker will suppress the activity of the latter and impose its own rhythm of contractions on the heart.
- Extrasystole is the appearance of an extraordinary cardiac contraction. Depending on the localization of the ectopic focus of excitation, extrasystoles are atrial, atrioventricular, and ventricular.
- Paroxysmal tachycardia is a sudden increase in rhythm (up to 180-240 heartbeats per minute). Like extrasystoles, it can be atrial, atrioventricular, and ventricular.
Violation of the impulse along the myocardium (blockade). Depending on the location of the problem that impedes the normal progression of the nerve impulse from the sinus node, the blockade is divided into groups:
- Sinoauricular block (impulse does not go further than the sinus node).
- Atrial block
- Atrioventricular block (impulse does not pass from the atria to the ventricles). With complete atrioventricular block (grade III), a situation becomes possible when there are two pacemakers (sinus node and focus in the ventricles of the heart).
- Intraventricular block.
Separately, dwell on the blinking and flutter of the atria and ventricles. These conditions are also called absolute arrhythmia. In this case, the sinus node ceases to be a pacemaker, and in the myocardium of the atria or ventricles multiple ectopic foci of excitement are formed, giving the heart a rhythm with a huge frequency of contraction. Naturally, in such conditions, the heart muscle is not able to adequately contract. Therefore, this pathology (especially from the ventricles) poses a threat to life.
Heart rate
The pulse at rest in an adult is 60-80 beats per minute. Of course, this indicator changes throughout life. Pulse age is significantly different.
Heart rate table |
Age | Heart rate (beats per minute) |
1st month of life | 130 - 140 |
1 month - 1 year | 120 - 130 |
1 - 2 years | 90 - 100 |
37 years | 85 - 95 |
8-14 years old | 70 - 80 |
20-30 years | 60 - 80 |
40 - 50 years old | 75 - 85 |
Older than 50 years | 85 - 95 |
There may be a discrepancy between the number of heart contractions and the number of pulse waves. This happens if a small volume of blood is thrown into the vascular bed (heart failure, decreased amount of circulating blood). In this case, fluctuations in the walls of blood vessels may not occur.
Thus, the human pulse (the norm for age is indicated above) is not always determined on the peripheral arteries. This, however, does not mean that the heart also does not contract. Perhaps the reason is the reduction in ejection fraction.
Voltage
Depending on the changes in this indicator, the pulse also changes. The characteristic of the pulse by its voltage provides for the division into the following varieties:
- Hard pulse. It is caused by high blood pressure (BP), primarily systolic. Pinching the artery with your fingers is very difficult in this case. The appearance of this type of pulse indicates the need for urgent correction of blood pressure with antihypertensive drugs.
- Soft pulse. The artery contracts easily, and this is not very good, because this type of pulse indicates too low a blood pressure. It can be due to various reasons: a decrease in the volume of circulating blood, a decrease in vascular tone, and inefficiency of heart contractions.
Filling
Depending on the changes in this indicator, the following types of pulse are distinguished:
- Full. This means that the blood supply to the arteries is sufficient.
- Empty. Such a pulse occurs with a small amount of blood ejected by the heart into systole. The causes of this condition can be pathology of the heart (heart failure, arrhythmias with too high a heart rate) or a decrease in blood volume in the body (blood loss, dehydration).
Heart rate
This indicator combines the filling and pulse rate. It depends primarily on the expansion of the artery during contraction of the heart and its subsidence during relaxation of the myocardium. The following types of pulse are distinguished by size:
- Large (high). It occurs in a situation when there is an increase in the ejection fraction, and the tone of the arterial wall is reduced. In this case, the pressure in the systole and diastole is different (for one cycle of the heart, it increases sharply, and then decreases significantly). The causes leading to the appearance of a large pulse may be aortic insufficiency, thyrotoxicosis, and fever.
- Small pulse. Little blood is ejected into the vascular bed, the tone of the arterial walls is high, pressure fluctuations in systole and diastole are minimal. The causes of this condition: stenosis of the aortic orifice, heart failure, blood loss, shock. In especially severe cases, the pulse value may become insignificant (such a pulse is called filiform).
- Uniform pulse. This is how the value of the pulse is normal.
Pulse waveform
According to this parameter, the pulse is divided into two main categories:
- Fast. In this case, during systole, the pressure in the aorta rises significantly, and rapidly decreases in the diastole. Fast pulse is a characteristic sign of aortic insufficiency.
- Slow. The opposite situation, in which there is no place for significant pressure drops in systole and diastole. Such a pulse usually indicates the presence of stenosis of the aortic orifice.
How to properly examine the pulse?
Probably everyone knows what needs to be done to determine what kind of pulse a person has. However, even such a simple manipulation has features that you need to know.
The pulse is examined in the peripheral (radiation) and main (carotid) arteries. It is important to know that with a weak cardiac output at the periphery, pulse waves may not be detected.
Consider how to palpate the pulse on the arm. The radial artery is available for examination on the wrist just below the base of the thumb. When determining the pulse, both arteries (left and right) are palpated. There may be situations where pulse fluctuations will not be the same on both hands. This may be due to compression of the vessel from the outside (for example, a tumor) or blockage of its lumen (thrombus, atherosclerotic plaque). After comparison, the pulse is evaluated on the hand where it is palpated better. It is important that when examining pulse fluctuations on the artery there should be more than one finger, but several (it is most effective to grasp the wrist so that 4 fingers, except the thumb, are on the radial artery).
How is the pulse on the carotid artery determined? If at the periphery the pulse waves are too weak, you can study the pulse on the main vessels. The easiest way to try to find it on the carotid artery. To do this, two fingers (index and middle) must be placed on the area where the indicated artery is projected (at the front edge of the sternocleidomulus higher than the Adam's apple). It is important to remember that it is impossible to examine the pulse from both sides at once. Pressing two carotid arteries can cause circulatory disorders in the brain.
The pulse at rest and at normal hemodynamic parameters is easily determined both on the peripheral and central vessels.
A few words in conclusion
The human pulse (the norm for age must be taken into account during the study) allows us to draw conclusions about the state of hemodynamics. These or other changes in the parameters of pulse oscillations are often characteristic signs of certain pathological conditions. That is why the study of the pulse has an important diagnostic value.