 Arterial pulse is a pressure wave that travels along the arteries when left ventricle contracts which actually expands the arterial wall and this expansion of the arterial wall is felt as pulse. So first point to note is that it is not due to the blood flow, it is actually a pressure wave whose velocity is much more than the velocity of the blood flow and the velocity of this pressure wave changes from if we see the central arteries that is the aorta towards the peripheral arteries. In central arteries actually it is quite less approximately 4 meter per second and in peripheral arteries it is 16 meter per second. So if we feel this pulse the contour which is felt that is how the pulse is coming and how the pulse is going away that is known as the pressure waveform or the contour or character of the pulse that is felt differently in central versus the peripheral arteries and in central arteries we actually palpate the carotid artery to feel this arterial pulse waveform. In the peripheral arteries because of increased velocity and actually there is decreased compliance of these peripheral arteries the pulse is felt more rapid and is actually spiking. So the peak is of greater height in peripheral arteries compared to that of the carotid artery. So to assess the pulse waveform we have to palpate the carotid artery. So let us see what is this normal pulse waveform. Well due to the ventricular contraction what happens that the pressure starts rising and because of this pressure there is blood flow also into the aorta. Now this creates two pressure waves in the artery okay due to the ventricular contraction. Then we know that when the ventricular contract in the second ejection phase actually the pressure starts falling. So here also we see a fall in the pressure until and less there is closure of the aortic valve. So at this point there will be closure of the aortic valve and because of this closure there will be vibrations set up. Plus little bit backflow of blood will also happen which will create a little bit notch in the falling pressure. So this is the falling pressure which was happening and due to the closure of the aortic valve little bit rise in pressure is seen. So this is the normal pulse waveform and it has different components. Let us see what are the components. So first we talked about that from beginning till this part this part is happening in the systole phase of the cardiac cycle and this second part is happening during the diastole phase. So if we see in the systole phase two waves are seen this is the percussion wave and this is the tidal wave. Now normally these two even though I have drawn a separate normally these two are felt as one only they are not felt as two different peaks. Why? Because they are occurring too fast almost together they are occurring so they are not felt as two different peaks. However remember this percussion wave and tidal wave because in certain conditions when they do not occur simultaneously then they will be felt as two different peaks. Now there are certain names here which we should remember this entire normal pulse waveform is known as catacytic pulse catacytic pulse okay. This is the normal pulse waveform then it has two different limbs this is the anacrotic limb and the second one is the diacrotic limb. So this falling phase is the diacrotic limb in which the beginning part of the falling phase is due to the late part of the ejection phase and when the diastole starts with the closure of the aortic valve so here if we record it is happening at the level of second heart sound along with the second heart sound and this uprise little bit uprise is known as diacrotic notch okay. So there are certain terms which you should remember. Now with this simple explanation let us directly go into the abnormal pulse waveforms. So here I have drawn a normal pulse waveform and before we jump into the abnormal waveforms little bit physiology here we should remember that this contour or character of the wave depends on certain things and one is stroke volume because stroke volume will determine the peak of the pulse then ejection velocity just remember this we will bring on these factors when we are discussing about abnormal waveforms then there is vascular compliance vascular compliance is important because if vascular compliance is less then we will see more peak of the waveform as we said that in peripheral artery there is less vascular compliance so there we actually feel the spiking pulse and finally there is systemic vascular resistance that is the peripheral resistance so these factors influence how these pulse forms will be. So let us directly jump into the abnormal pulse. So first abnormal pulse which we will be discussing is pulses parvas pulses parvas and this term parvas means low amplitude pulse so if we draw on this the pulse will be something like this the amplitude will be less and what we said that the amplitude depends upon what it depends on the stroke volume so here means that the stroke volume from the heart is less that is why we are getting the low amplitude pulse and what can be the cause of this whenever there is low blood in left ventricle or the strength of contraction of the left ventricle is weak so this can occur in case of shock or in case of the mitral stenosis because in mitral stenosis the amount of blood which comes to the left ventricular that is the endostatic volume will be less so this is pulses parvas. Next is pulses etardus the term etardus means slowly rising pulse it is like tired okay slowly rising pulse so if we draw it here the peak will be same but it will rise slowly okay and when can this occur one example of this is left bundle branch block when actually the whole ventricle doesn't contract together so the force generated by the ventricle is not that much slowly the force will be generated however the peak will be same only so that is pulses etardus now we combine these two so there becomes another pulse that is pulses parvas etardus so in pulses parvas etardus the pulse is low amplitude and slowly rising also so if we draw it how it will come it will be something like this right so it is slowly rising as well as the amplitude is less and this kind of pulse is seen in aortic stenosis now can you tell why it is occurring in aortic stenosis because you see in aortic stenosis stroke volume is less so we don't see that peak and ejection velocity is also less so that is actually a slowly rising pulse because there is some outflow obstruction and that leads to slowly rising pulse now in severe aortic stenosis sometimes you might have seen the pulse form which is drawn is something like this actually right so what we see is little bit not here in the systolic uprise and this kind of pulse in aortic stenosis is known as anacrotic pulse so the normal pulse which we saw what was the name that was the catechronic pulse this pulse which is notched in aortic stenosis that is known as anacrotic pulse so what we are seeing here is that there is little bit splitting so there is a percussion wave and this is a tidal wave but this is not same as the pulses bisphirians remember little bit just not is seen actually I should draw a little bit like this okay and when feeling the pulse you will feel only one peak but better this is seen when we are recording the pulse so why there is this splitting because as I told you that in catechronic pulse the percussion wave and tidal wave are coming together but here due to little bit obstruction what is happening that this tidal wave comes little bit later so these two waves kind of separate so this kind of notched pulse in the rising phase of the pulse waveform that is known as the anacrotic pulse and seen in aortic stenosis moving on to the next waveform that is the water hammer pulse or the corrigans pulse this pulse is seen in case of aortic regurgitation and how it is seen there is a rapid upstroke and there is a rapid fall of the pulse waveform so there is fast uprise and fast fall why it is occurring well in aortic regurgitation there is increase in blood in left ventricle why it is there because the aortic valve is not closing so in the previous diastole the blood flow occurs back into the left ventricle causing increase in the end diastolic volume in the left ventricle this leads to increase in a stroke volume due to the frankstyling mechanism more end diastolic volume leads to more stroke volume and this leads to increase in the upstroke so that we see this rapid fall see actually the peak is more the peak is more okay so there is a fast uprise then again during diastole what happens the aortic valve doesn't close so there is back flow of the blood so that pressure wave is set in so this back flow causes rapid runoff of the blood into the left ventricle so that leads to the rapid fall so this one is simple seen in aortic regurgitation now moving to the difficult ones which we find little bit difficult to understand and that is pulses bisvariance what is this bisvariance means that there are two peaks which we see in the systolic part of the pulse waveform so what we see here is something like this okay so two peaks are seen in the systolic part of the wave itself so two peaks mean simple what we have seen that there are two waves percussion wave and tidal wave so actually they have separated this is the percussion wave and this is the tidal wave and why it is occurring first case in which it occurs is severe aortic regurgitation so what is happening in severe aortic regurgitation that we saw that how there is increase in the stroke volume this also leads to increase in the ejection velocity of blood from the left ventricle into the aorta now because of this increased ejection velocity there is fall in pressure in aorta why it is occurring well it is based on the Bernoulli's phenomena that whenever the kinetic energy increases the potential energy actually decreases because the total energy is constant and this component of the energy is basically the pressure exerted on the lateral walls so when this kinetic energy is increasing because increase of the ejection velocity the lateral pressure is decreasing now this causes a pull of the wall of the aorta so the aortic diameter decreases understanding so if diameter decreases what is happening it is actually creating some kind of block in the flow compared to the normal condition and hence there will be delay in the next part of the waveform so that is the tidal wave so any block if occurs that will lead to kind of splitting between the percussion wave and the tidal wave and that will create two peaks in the rising part of the pulse waveform so one condition as I told you that it occurs in severe air another condition it occurs in hocm what happens in hocm the left ventricle is hypertrophied so left ventricle hypertrophy it means the force of contraction which occurs will be much more and this will lead to increase in the ejection velocity correct so initially we will see this pressure wave but in hocm there is dynamic obstruction in the outflow so this obstruction again it will delay this next part the outflow of the blood will be delayed and actually in hocm there is little bit difference from what we see in aortic regurgitation what we see there is a rapid upstroke and then this tidal wave is little bit delayed and this is better appreciated by means of recording so this is second reason of pulses disvariance third reason third reason is ar plus aortic stenosis and can you tell why again because ar will cause the increased ejection velocity and there will be percussion wave but the obstruction in the flow will be caused by the aortic stenosis hence causing the splitting of the percussion wave and the tidal wave so this is pulses bisvariance contrasting with pulses bisvariance there is another pulse with two peaks that is known as pulses dichroticus pulses dichroticus or dichotic pulse here also we see two peaks but the second peak occurs in case of the diastolic part of the wave so in pulses bisvariance before the closure of the aortic ball we are seeing two peaks that is in the systolic part of the wave in pulses dichroticus one peak we see in the systolic part and the other peak we see in the diastolic part that is pulses dichroticus and when does this occur this occur when there is increase in peripheral resistance why as we discussed in the normal condition that this is the diastolic part and what happens that after closure of the aortic valve there is runoff of blood in the peripheral circulation but when there is increase in the peripheral resistance in that case this runoff is inhibited the velocity will not be that much instead with the aortic valve closure the backflow which is occurring and the vibrations which are set up are much more because the blood is not flowing forward so it will set up more vibrations so we see two peaks one in systole one in diastole and pulses dichroticus when there is increase in peripheral resistance and one common cause is hypovolumic shock now remember that this is very commonly confused with pulses bisvariance if we feel both in both we feel two peaks so to differentiate between the two the recording of the pulse waveform is required next moving on to pulses alternance pulses alternance is something which is basically change in the amplitude of the pressure waveform with successive beats so beat to beat variability of pulse amplitude so we have to draw multiple waveforms for this so maybe this is the amplitude in first rate this becomes amplitude in second b then again then again decrease and this type of pulse occurs in case of severe heart failure why well in heart failure the stroke volume will be less right so when a stroke volume is less what will happen to the systolic uprise of the waveform it will be less right but due to this decreased stroke volume in the first week you see the end diastolic volume which is present in the left ventricle in the second beat will increase right because the percentage of blood which has been ejected out was less so end diastolic volume increase and again due to the frank styling mechanism this will lead to increase stroke volume in the second beat so then we get a rise now again the blood volume which is present in the left ventricle again end diastolic volume will become less so we will get less amplitude of the pulse waveform so this is known as pulses alternance because the amplitude is alternating more and then less coming to the last type of abnormal pulse that is pulses paradoxes and pulses paradoxes is appreciated while recording the blood pressure remember so what is this pulses paradoxes pulses paradoxes is greater than 10 millimeter mercury fall in systolic blood pressure with inspiration so normally also with inspiration there is fall in systolic blood pressure but when this fall becomes greater than 10 millimeter mercury that is known as pulses paradoxes so the name is a little bit confusing actually there is exaggeration of the normal phenomenon it is not a paradoxical condition but still the name is pulses paradoxes so let us see why first during inspiration there is fall in blood pressure actually when we inspire there is negative intrathoracic pressure and due to this negative intrathoracic pressure there is pooling of blood in pulmonary circulation so less blood is going to the left ventricle causing decrease in the end diastolic volume in the left ventricle and hence there is decrease in the stroke volume from the left ventricle and since stroke volume or the cardiac output is the determinant of systolic blood pressure there is fall in systolic blood pressure during inspiration but when this response is exaggerated there is more pooling of blood in pulmonary circulation and less end diastolic volume in left ventricle during inspiration that leads to pulses paradoxes so how to record this for appreciating this pulses paradoxes what we have to do that we have to record the blood pressure and we have to note the systolic blood pressure that is the point where corotkov sound start coming then slowly very slowly we have to decrease the mercury level okay decrease the pressure and what happens that you will see that there is a point that corotkov sounds come here continuously so the first level when you hear these corotkov sounds they occur only during the expiration phase of the respiration okay and here they are independent of the phase of the respiration so they are here they are occurring continuously but here from the beginning to this new level where this corotkov sounds are occurring continuously they occur actually intermittently that is only during the expiration phase so we note down these two levels and see how much is the difference between the two levels and when this difference is more than 10 millimeter mercury then it is known as pulses paradoxes obviously easy to tell but you need a lot of practice to record to appreciate the presence of pulses paradoxes and what are the causes of this pulses paradoxes there is tension nemothorax there is pulmonary embolism severe obstructive lung disease so these are basically the respiratory problems which are occurring and there is pellicardial tamponade which will not allow the blood to flow into the left ventricle so that was all about the various pulse forms few things to remember that normally the pulse waveform is felt in the carotid artery however only the pulses bisferias the pulse with two peaks in the systole phase is better femoral and brachylatory so I hope you understood the physiological abnormalities which will lead to various abnormal pulse waveforms because we saw how changes in the stroke volume ejection velocity vascular compliance and peripheral resistance was changed in the pulse waveforms thanks for watching the video if you liked it do press the like button share the video with others and don't forget to subscribe to the channel physiology open thank you