Feeds:
Posts
Comments

Posts Tagged ‘e and a velocity swings’

Heart is a dynamic organ . It can alter  its force of contraction with every beat  according to the needs.Generally it responds to  length  of  previous  diastole.This is famously called frank starling law , ie the force of contraction is directly proportional to the end diastolic fiber length. So changing diastolic  duration as in atria fibrillation classically result in varying amplitude of LV contraction and pulse volume.

However , the commonest cause for  pulsus alternans  is  due to  severe left ventricular systolic dysfunction .There has  always been a suspicion about the existance of  beat to beat variation in  diastolic function as  well.  We have recently observed a  new* explanation for pulsus alternans .We know AV inflow is subjected to respiratory swings . Non  respiratory swings in mitral and tricuspid valves are rarely described. This pattern is now increasingly recognised.

These  non respiratory swings in the mitral inflow doppler pattern  is seen in  some of the  patients with hypertension and LVH.This  probably confirms the existence of  beat to beat variability of diastolic function . This phenomenon is relatively a new observation . Such pattern are common in patients who have had a recent hypertensive failure .

 

Here is a doppler of mitral inflow recorded from a patient with hypertension with LVH .

This is the doppler mitral inflow profile of a patient with Hypertension, LVH and class 2 dyspnea .Note the non respiratory swings in both "e" and "a" velocity

It is proposed  to  define  a new class of diastolic dysfunction that can be referred to as diastolic  mitral inflow  alternans .This phenomenon probably indicates a more severe grade of diastolic dysfunction.At the molecular level this is related to  undulating flux  in the calcium uptake from cytoplasm into SERCA .There is one more possible explanation for diastolic alternans  -Left atrial  dysfunction .

Occasionally one can visualise  a chaotic pattern of  diastolic filling waves  (e=a e>a a> e )  Such patterns are thought  to be markers of impending acute diastolic shutdown .

Further  analysis of  this  mitral doppler inflow pattern will be reported  later.

Reference

* Though we observed this for the first time , this is not a new phenomenon .There are few reports available in the literature.

http://www.sciencedirect.com/science/article/pii/S0735109785800358


http://www.sciencedirect.com/science/article/pii/S0894731706012818

Read Full Post »