Posts Tagged ‘jvp’

Jugular vein is a natural non invasive right heart catheter inserted permanently in the right atrium . It faithfully reflects the right heart hemo-dynamics  during  every heart beat.

The information you gather is dependent upon the time you spend and mind you you apply on this biological catheter.Wenke back did so nicely he was able to identify progressive a and c interval and a drop of c wave  before even the ECG machine was invented.

The following table  illustrates  the difference

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V wave  is one of two positive  upstrokes   seen  in JVP.  Physiological  “v” wave is due to  atrial filling  and reaches the peak at late  systole , while pathological ” v” waves  are often  due to tricuspid regurgitation  . It is  a mid systolic wave .It is a fusion of  “c”and “v” waves .

Here is a patient  with dilated cardiomyopathy with severe tricuspid regurgitation  who presented with prominent neck veins.

there is no difficulty in identifying the  v wave . Careful acuity will reveal  a  sharp  “a”  wave as well !

JVP pressure wave form of tricuspid regurgitation showing classical systolic cv waves

How to measure the amplitude of  v waves ?

In JVP,  there is a baseline oscillating column . Individual wave  spikes  occur over and above this baseline . Hence  technically there  should be two measurements  , but we take only the  top most part of the oscillating  column.

What is the indirect evidence for tall  v waves ?

Physiologically “y” descend is  integral part of v wave (In fact ,  “y” descend  can be referred to as down stroke of  “v” wave )  .For every  tall “v” wave  there  must be  a prominent  “y”descent . (Probably  constrictive pericarditis is an important exception ! )

If  “y” descend is not rapid but shallow one can suspect two conditions

  • Tricuspid stenosis
  • Significant RV dysfunction

How to differentiate v waves from a waves ?

“V” wave  is a passive filling wave hence it raises  slowly , has  relatively   shallow summit and  occurs in   mid or late-systole  . “A”waves are  due to active contraction of atria . It is a  sharp pre-systolic wave . One practical way to recognise   “a” wave is ,  it  never stays in the eye , it just flickers.  If your eye sees a sustained wave for more than  a fraction of  moment it can not be  “a”  wave ! Another point that may be useful is  “a” is taller than “v” in  right atrium .


Click below to hear the murmur of TR (Courtesy of Texas heart institute )


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AV dissociation is  common clinical situation that can occur  during both    bradyarrhythmias  and tachyarrhythmias .


  • Complete heart block
  • During pacemaker rhythms


  • Accelerated junctional  rhythm
  • Idioventricular  rhythm
  • Ventricular  tachycardia

AV dissociation is essentially an  ECG diagnosis. But it is associated with some  clinical  signs   ,which can be detected by an astute physician in the bedside. At rapid heart rates  it may be really difficult at times to recognise theses findings, but a  cardiology fellow should look for these whenever they encounter AV dissociation  in ECG.

  1. Varying pulse volume
  2. Varying korotkoff  sounds during BP measurement.
  3. Cannon a waves in JVP
  4. Varying intensity of first heart sound on auscultation
  5. Mitral regurtitant murmur may be heard
  6. Hypotension in compromised hearts

What is the mechanism of clinical signs of AV dissociation ?

During AV dissociation , the atrial and ventricular contractions occur  out of phase  and the sequential contraction  is lost. So atrial contractions  might  occur with a closed AV valves .  This result in reflux of blood into the neck resulting in cannon waves . It may be visible only in few beats as the retrograde conduction VA conduction , is highly variable.

Further , only some atrial beats contribute for ventricular filling some do not.This results  in varying LV volumes and this  could result in changing pulse volume.Occasionally the ventricular and atrial   contraction occur simultaneously  .When this happens ,  some amount of blood  reguritates through the open tricuspid valve and mitral valve  which result in MR or TR .

Clinical utility

This could be important , in differentiating  the perennial  issue   of decoding the   wide qrs  VT from  SVT with  aberrancy .A rapid clinical assessment  here could  aid in the diagnosis  of VT  by  identifying  AV dissociation  . An experienced cardiologists will realise even in a given  ECG  with VT  identifying or ruling out  AV dissociation is not always a  pleasant excercise !

In this era of  high tech gadget  oriented cardiology is it not too much  to call for clinical   recognition of  this  entity ?

Definitely not , if  we know Wencke bach  recognised  the classical type 1 2nd degree  AV block in late 19th century even before the ECG machine was  invented ,

Simply by looking at the neck , by carefully observing progressive prolongation of  distance between a and c waves and subsequent dropping of c waves . Amazing isn’t it ?

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