What is the difference between A wave and Y wave in JV pulse, same thing?

[cooldude89]

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What is the difference between a wave and Y wave in JV pulse, same thing?

A wave is right atrial contraction is that not the same thing as
Y wave which is emptying of right atrium (same thing as right atrial contraction)

 

[Charles_Carmichael]

The a wave is due to the back-pressure from atrial contraction, resulting in venous distension. So, this occurs in late diastole, just before ventricular activation.

The y descent, on the other hand, is the decrease in right atrial pressure during early diastole, once the tricuspid valve opens (after the ventricle relaxes). So, no, the y descent is not the same as right atrial contraction. The y descent is due to passive filling of the ventricle during early diastole and it occurs before atrial contraction.

Hope that helps.

 

[Phloston]

In even more simple terms:

y-descent is passive ventricular filling

a-wave is active atrial contraction (atrial systole)

 

[cooldude89]

but why would there be passive ventricular filling first and then the atrial contraction, shouldn't the atria contract first hence pushing the blood in to the ventricle passively filling them? I am confused..

Which parts of the JP pulse are systole and which ones diastole, i think only a waves is diastole and rest are systole right?

 

[Charles_Carmichael]

but why would there be passive ventricular filling first and then the atrial contraction, shouldn't the atria contract first hence pushing the blood in to the ventricle passively filling them? I am confused..

You should review the cardiac cycle. Passive filling of the ventricles occurs before atrial contraction. At rest, atrial contraction doesn't increase ventricular volume significantly -- most of the filling is passive. Remember, atrial contraction does not result in passive filling; it's active. So, check out BRS physio or something and review this. Once you have a good understanding of the cardiac cycle, the different waves and descents will make much more sense and will be much easier to remember.

 

[withrye]

but why would there be passive ventricular filling first and then the atrial contraction, shouldn't the atria contract first hence pushing the blood in to the ventricle passively filling them? I am confused..

Which parts of the JP pulse are systole and which ones diastole, i think only a waves is diastole and rest are systole right?

Start with the end of systole, when the ventricle has just finished full contraction.

There is Venous return into the atrium (against a closed tricuspid), increasing its pressure (v wave).
Then the tricuspid opens, and the atrium passively emptYs into the ventricle (y descent).
Towards the end of the emptying, the atrium contracts to get extra blood out (a wave). (The contraction pushes blood backwards as well as forwards)
Then the ventricle Contracts and the triCuspid closes, pushing the valve into the atrium (c wave).
At this point the atrium also relaXes, causing a drop in pressure as blood passively enters the atrium (x descent).

It's important to both know the cardiac cycle as well as know that the Jugular Venous Trace is NOT a measure of contractility or some sort of EKG. The wave doesn't go up or down just because something is contracting or relaxing. The wave goes up or down based on whether valves are open or closed, chambers are contracting or relaxing, and what that does to the pressure seen by column of venous blood behind the atrium.

 

[cooldude89]

ok thanks i understand it now