Sunday, April 23, 2017

'A' wave in JVP : Mnemonic and explanation

Hi everyone. So JVP is one of the most theoretical clinical signs I've ever studied. And though parts of it are logical , I find it tedious to memorize all causes for a particular finding.
So I've prepared a Mnemonic for prominent a waves.
Here goes.

The A wave is a positive wave of the JVP.
It represents the Right Atrial pressure during systole.

Causes of a prominent a wave
Remember :

C - Cor Pulmonale
R - Right heart Failure
P - Pulmonary stenosis
T - Tricuspid stenosis
S - The S tells you it's Stenosis for P and T.

The a wave essentially represents the pressure in the Right atrium during systole.
So any condition that causes this pressure to increase would cause a prominent A wave.

Cor Pulmonale and RVF are basically congestion in RV causing elevation of pressure in the RV.
This means the atrium needs to pump with greater force into the Ventricle for the venous return to enter the Ventricle. This increases the RA pressure causing prominent a wave.

Pulmonary Stenosis leads to accumulation of blood in the RV and this follows a similar fate as the above mentioned causes.

Tricuspid stenosis causes obstruction to the flow of blood from RA to RV. Thus accentuating the pressure in the RA.

That's the Prominent a wave for you !

Now there's something called the Cannon a wave.
These represents contraction of the RA against a closed Tricuspid valve.
The causes of this include -
A- V dissociation.
Heart blocks.
Ventricular arrhythmias - V tach , Ventricular premature complexes and Ventricular pacing.
The a wave would be absent in Atrial fibrillation as the atrium is functionally not pumping at all , and just vibrating.

These are the a wave findings for you !
Hope this helped
Stay awesome.
~ A.P. Burkholderia

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