 When we talk about cardiac cycle, it is very important that we understand the various pressure and volume changes in different phases of the cardiac cycle and in different chambers of the heart. So, these pressure and volume changes in the different chambers of the heart actually change when there is any abnormality in heart. For example, if there is a mitral stenosis, tricuspid stenosis and the pressure and volume changes obviously are going to change. Now one of these changes is the changes in the right atrial pressures and these right atrial pressure changes during the cardiac cycle can be studied by analyzing the jugular venous pulse form or jugular venous pressure. So, let us see what is the jugular venous pressure and how it changes during the cardiac cycle. First of all obviously we should know what are the phases of the cardiac cycle. So, let us try to understand with a schematic diagram and I will be here focusing only on the right side of the heart when we talk about JVP. So, suppose this is the right atrium and here they will be opening of the superior venacheva into the right atrium through which there will be venous filling of the right atrium. Then right atrium empties into the right ventricle and there is a valve in between that is the tricuspid valve. Okay, now what are the various phases of the cardiac cycle? We see there is first atrial system first there will be obviously electrical activity. So, electrical activity starts from SA node then there will be P wave in the ECG. Right, so after the P wave there will be atrial systole then just after the atrial systole what happens that there will be closure of the tricuspid valve okay tricuspid valve will close and there will be start of the ventricular systole and ventricular systole first phase is iso volumetric contraction then there is a rapid ejection phase then there is slow ejection phase fine. After the slow ejection phase there will be the closure of the pulmonary valve and then will start the ventricular diastole phase that consists of iso volumetric relaxation then first rapid filling phase then there is slow filling phase and again there is further rapid filling phase second rapid filling phase which is basically caused by the atrial systole itself. So, here there is this rapid filling phase is coincidental with the atrial systole basically it is occurring due to atrial systole. So, in this various phases of the cardiac cycle what we see that right atrial pressure changes occur and let us see diagrammatically graphically what are the changes which occur. So, when we talk about the graphical changes we are talking about the jugular venous pulse form and why we are talking about jugular venous pulse form because the pressure changes which happen in the right atrium you see they are reflected in the internal jugular vein this internal jugular vein directly drains into the superior vena kiva and has no valves no valves okay. So, whatever changes are happening in the right atrium these pressure changes will be reflected directly in the internal jugular vein and we can visualize this internal jugular vein and we will be able to elucidate what are the pressure changes happening in the right atrium. So, first is the atrial systole. So, during atrial systole logically what is happening there is contraction of the right atrium right. So, this chamber is decreasing in size and pressure is building okay. So, atrial systole there is obviously entry of blood into the ventricle correct, but you see as I told there is no valve between the vein and the right atrium. So, what happens that whatever pressure changes are there they are reflected into the internal jugular vein as well simple see blood will flow into the ventricle and some amount of blood little bit back flow will also occur because there are no valves and that will be seen as a wave in the jugular venous pulse and that wave is basically a wave. So, there is a positive wave seen that is a rise in pressure which occurs and that is known as a wave okay. Then just after the atrial systole the atria will start relaxing back again okay. So, it is going to come back here again. So, there will be a descent in the pressure because it is relaxing. So, the pressure will again fall. So, that is known as x wave fine. But you see as the atria start relaxing there will be ventricular systole right. So, ventricular chambers have started contracting and first phase will be the iso volumetric contraction. So, the blood is not moving out but the ventricles are contracting the pressure is building inside the right ventricle and because of this there will be little bulging of this tricuspid valve into the atria and hence there will be a small rise in pressure again in the JVP form. So, this wave is known as C wave. So, you see the descent in pressure is interrupted by a little rise in pressure and that is known as C wave. Then after iso volumetric contraction what will happen? The pulmonary valve is going to open and the blood will start flowing into the pulmonary atria. So, that is the rapid ejection phase and slow ejection phase and again due to this this will come back to the normal place and you know that during ventricular systole what is happening atria are continuously relaxing ok. So, we will that descent of X wave will resume ok. So, this is X wave. So, that will continue so that there will be fall in the pressure of the right atrium that is seen as a descent of the JVP. So, what has happened that this part A wave we got due to the atrial systole and the beginning of the C wave it denotes that ventricular systole has started and this is the atrial diastole coincides with the ventricular systole what we see that the descent in the pressure in the right atrium. Now, obviously with the relaxation of the right atrium the right atrium is continued to be filled by blood. There will be a point that the filling is itself going to increase the pressure in the right atrium. See initially here also atrial filling is continuing but the pressure is going down why it is going down because the right atrium is continuously relaxing but after a point due to too much filling what will happen that this pressure wave again will rise. So, that is known as V wave and why it is occurring due to the venous filling of the right atrium. So, again we get a positive pressure wave and what about the happening in the ventricles yes ventricles systole is continuing understanding. So, during this entire phase the ventricular systole is happening. Now, once the ventricular systole is over and after iso volumetric relaxation what will happen that this valve is going to open and with opening of the valve there will be emptying of the blood which is present in the right atrium into the ventricle. So, this is just passive emptying atria is not contracting atria is still relaxing but due to sudden emptying that is the rapid filling phase of the ventricular diastole we start getting a negative waveform and this is known as Y wave. So, here ventricular systole has ended right and here ventricular diastole has started. So, again what we see A wave due to the atrial contraction right and this is atrial systole then the X wave starts but it is interrupted by a C wave due to the iso volumetric contraction of the ventricle then there is a negative wave that is the X wave which happens because due to the continuing atrial relaxation also due to the ventricular ejection this closed tricuspid valve is pulled a little bit down okay. So, simple terms we will remember that it is due to atrial relaxation then V wave that atrial diastole is continuing and the venous filling of the atria is too much and then there is Y wave due to the ventricular diastole the filling of the ventricular is started because of the opening of the tricuspid valve. So, that is very basic waveforms of the JVP let us see a little mnemonic to remember these waveforms and then we will go into further details. So, here we are seeing two JVP waveforms right this is one and this is the second JVP waveform and what we saw that various waves of JVP occur in a single cardiac cycle. So, this is happening in a single cardiac cycle and what we saw that there are various waves what are the waves A wave C wave X wave V wave and Y wave AC and V are the positive waves pressure changes increasing and X and Y is the negative waves that the pressure is decreasing. So, what is the mnemonic for this A wave is because of atrial contraction. So, how I remember is A for A ok A wave is for atrial contraction then C wave is due to the isovolumetric contraction. So, that where we took the first letter here we are taking the last letter that is the isovolumetric contraction of the ventricle. So, this part is atrial systole and isovolumetric contraction of the ventricle causing tricuspid valve bulging into the atria. So, that also here C is there so that also I take a C wave. So, here ventricular systole has started right then X wave is due to atrial relaxation relaxation ok. So, X of relaxation that is atrial relaxation right then V wave that is due to the venous filling of the atria venous filling right. So, you see I am talking in terms of atria mostly here for the mnemonic atrial contraction atrial relaxation X wave venous filling of the atria is V wave only here I told about the isovolumetric contraction or to remember other way around in terms of atria tricuspid valve bulging into the atria. Then at the peak of the V wave what happens that there is opening of the tricuspid valve and it causes starts atrial emptying atrial emptying. So, how I remember Y of emptying is Y wave and if we see the phases of the cardiac cycle here was a ventricular systole and here the ventricular diastole has started and this will continue till here right because the atrial systole is basically a part of the ventricular diastole only and this hole is basically from here to this portion is atrial diastole. So, that is the relationship between the phases of the cardiac cycle and jugular venous pressure waveform. Now, let us move on to how this JVP is visualized and how it is measured at bedside. For measurement what we do is we ask the person to lie down in 45 degree position and then we palpate on the chest and identify the angle of Lewis. After identifying angle of Lewis we put a ruler there okay so this is a ruler and it is placed vertical to the ground okay so this is a horizontal position and ruler is placed vertically on the angle of Lewis. Now, we look at the neck okay now remember normally JVP is usually not seen so when we ask the person to turn the head to the other side because we have to see on the right side right. So, we ask the person to turn the head to the left side and we put a torch light okay focus a torch light on the neck and here there is sternocleidomastoid muscle so internal jugular vein which is the one which has no valves and directly communicates via the superior vena keva to the right atrium runs just here just middle to the sternocleidomastoid muscle. So, in physiological conditions this JVP will not be visualized so what we do is that we put another scale at the level of the clavicle okay and that has to be put again perpendicular so if this is the level it is put perpendicular exactly perpendicular and we note the level the height at which it is crossing on the vertical ruler so here normally this height will come to around three centimeters and remember we are talking when the JVP is not visible so at the level of the clavicle we will put the second ruler and then also we will see some height that is around three centimeter so how much is the normal JVP well you see the distance of this angle of louise from the center of the right atrium it is five centimeters okay that is why angle of louise is taken as the standard point for measurement of the right atria pressure now this distance is five centimeter right and this distance is three centimeters so how much is the total JVP it is eighth centimeter and since we are seeing the level of the blood column in the JVP and which has water so basically JVP we express in terms of eighth centimeter of water so this is the normal JVP now if this JVP waveforms which we were talking they can be seen in the internal jugular vein much above this level okay so you are able to visualize clearly then if you put a ruler then what will happen that this height is going to increase and there will be rise in the JVP okay so that is known as a raised JVP so that is how you measure JVP there is another simpler way which can be done in bedside basically you ask the person to sit down and if venous pulsations are seen above clavicle in sitting position they are considered abnormal because in sitting position the distance between the clavicle and the right atrium is 10 centimeters okay so in sitting position if they are definitely seen above the clavicle that means JVP is more than 10 centimeters right so that is abnormal that is raised JVP now what do you actually see when you are looking for the pulsations in the internal jugular vein we are seeing the same waveform which we discussed before so if it is visible is it that the waveform which should be there is it normal or is it abnormal so as we saw that in one cardiac cycle there will be this is the complete JVP and basically the C wave which we saw it is basically an interruption of the descent wave so what we see actually is two positive waves so that is why JVP is known as being biophasic and two negative waves so we have to visualize very carefully it is very difficult you have to practice a lot to understand these JVP waveforms when you are actually visualizing in the patient so in one cardiac cycle you will see one rise one fall and then again one rise one fall so two rise and two fall you will see in JVP however if you compare it with the arterial pulsation arterial pulsation is only a single pulsation during a cardiac cycle so that is why arterial pulsation is known as monophasic and it is very important that when we are looking at the neck we differentiate between the arterial and venous pulsation so let us see what are the differences between arterial and in the neck which artery is there carotid artery is there so that pulsation we are talking about so arterial pulsation and venous pulsation we should differentiate as I told you that venous pulsation is biophasic so in a single cardiac cycle you will see two venous waves while arterial pulsation is monophasic right and which of these pulsations can you palpate arterial pulsation is the one which is basically expensile pulsation and that is why you can palpate this arterial pulsation while venous pulsation you can only visualize so it is only visible you cannot palpate this pulsation so that is the second difference coming to third difference this venous pulsation can be made to increase or decrease by means of certain maneuvers for example there is something known as abdominal jugular reflex abdominal jugular reflex what is this basically we press on the right upper quadrant of the abdomen and when we are doing that what is happening that there is increase in the venous return this increase in the venous return it is going to increase this venous pulsation however there will not be any change in arterial pulsation also you can as a person to change the posture which of these will change with the change in the posture it is jvp which is going to change with the change in the posture because you see that venous return again changes with the change in the posture so these things you should take note when you are looking for jvp now let's talk about certain abnormalities which you can figure out by looking at jvp so here i have drawn many jvp pulse forms which you will be seeing continuously when you are looking in the neck right and this one you are seeing in one single heartbeat right now remember that jvp also changes with inspiration and expiration during inspiration what happens that there is increase in the intrathoracic volume because your chest is expanding so there will be increase in the intrathoracic volume and with that there is suction pressure for the venous return to the heart so there is increase in the venous return if we change this craft to what will happen to jvp which change in the inspiration and expiration what we will see that initially if you are seeing jvp maybe suppose this is the neck maybe somewhere here with inspiration there will be fall in the jvp waveform so first is that obviously you will see it higher in some abnormality but in that if the waveform is normal with inspiration and expiration you will see that the height of the waveform in the neck has decreased so what will happen that it will go below so overall you see the waveform may will be similar but the height is lesser during the inspiration okay so that is one thing which you should remember because there may be certain abnormalities in which you don't see this fall in the waveform with inspiration so here we have the normal jvp here it is showing in the expiration phase and there it is showing in inspiration phase now let us see certain abnormalities so as I told you this one is a wave due to atrial contraction then there is c wave due to iso volumetric contraction of the ventricles then there is x wave due to atrial relaxation v wave due to the venous feeling of the atrium and then there is y wave due to the atrial emptying with the opening of the tricuspid valve now suppose you see that a waves have become stronger okay so while you are visualizing you see that one positive wave is coming much stronger than the other positive wave and since they are coming continuously you need to find out which wave is coming is stronger is it a wave or v wave for that what you do is you simultaneously palpate carotid artery right carotid artery you palpate and when will you feel the carotid pulsation only during the ventricular systole when the rapid ejection is started isn't it so when you are palpating the carotid artery suppose you feel the carotid pulsation it will be somewhere here if we match it with the jvp isn't it so if there is a wave which has become stronger and it is coming before the carotid artery pulsation then that is the a wave that has become stronger the one which is coming along with the carotid artery pulsation that is the v wave so this needs a lot of practice in theory it looks easy but you have to be actually with the patient and see a lot of patients to actually observe this and understand this what is happening coming to theoretical part suppose you see that a waves have got a stronger and we know that a wave is occurring due to the atrial contraction that means the atria is contracting with much force isn't it and this increase in force happens when the atria have to contract against your resistance so let us go back to our schematic diagram so this is the atria and this is the valve this is the ventricle when do you think will that atria have to contract with much force suppose when there is some block here isn't it so in a condition where tricuspid valves are not opening properly as in tricuspid stenosis we will see large a waves also these large a waves are seen in right ventricular hypertrophy which occurs in case of pulmonary stenosis pulmonary hypertension so when right ventricular hypertrophy develops what will happen that there is increase in pressure in the right ventricle because of some output block from the right ventricle to the pulmonary atria right and that happens in case of pulmonary stenosis pulmonary hypertension and to overcome this increased pressure in the right ventricle for the feeling to continue properly right atrium has to contract with a much greater force isn't it so in these cases also we will get large a waves so in tricuspid stenosis and right ventricular hypertrophy which may occur due to pulmonary stenosis pulmonary hypertension then we get large a waves the second wave is v wave right when will you get large v waves large v waves we said that v wave is due to what v wave is due to venous filling so here we are telling that right atrium is filling more that is why the b waves are becoming large and when that will happen that will happen in case of tricuspid regurgitation because you see the valves here have not closed during ventricular contraction and when the ventricles contract the blood will flow back into the right atrium and that is going to increase the pressure in the right atrium right so that will lead to large v waves so that is the abnormalities in the waves of the jvp now suppose waves are normal you don't see any abnormality in the waveform as such but overall there is increase in jvp right so in the neck when you see there is very high jvp but the waveforms there is no change that can occur in case of heart failure heart failure and that can also occur in case of fluid overload maybe due to some other condition like in case of itrogenic when we are giving fluid to the patient in that case we have to actually monitor the jvp because when fluid overload occurs then we will see high jvp heart failure also you see fluid overload occurs because the kidneys try to compensate and they retain more and more waters so in heart failure also you see increased jvp however you will see that there is no abnormality in the jvp waveforms then there may be another abnormality in which you don't see this normal fall in jvp with inspiration so what will happen you will see that it is like this only that is known as kuzmol sign kuzmol sign and that is seen in constrictive pericarditis so constrictive pericarditis does not allow proper filling of the heart so even in inspiration when the chest is expanding the pericardium is constricting the heart and it is not allowing more filling of the heart during inspiration so we see that instead of fall during inspiration actually there is rise in jvp during inspiration so it becomes opposite than that of the normal physiology so kuzmol sign is seen in constrictive pericarditis so that is very basic about the jvp some abnormalities we have discussed i have not told everything because i personally feel that for this you actually have to be with the patient see a lot of patients with raised jvp but just before ending i will also touch on something known as static jvp see here we are talking about various pulse forms okay so this is a pulsatile jvp but static jvp is one where you see that yes there is a definite rise in the internal jugular vein pressure which you will see as filling much filling of the internal jugular vein however you will not be able to see any of these waveforms that means that atrial pressure is not being communicated to the internal jugular vein we have seen that how the atrial pressures are being reflected as these various waveforms so if atrial pressure is not communicated to the internal jugular vein we will not see any waveform and that is seen in case of superior vena keva obstruction and that is static jvp so that's all for jugular venus pressure if you like the video do press the like button share the video with others and don't forget to subscribe to the channel Physiology Open thank you