Assessment of LV diastolic function primarily depends on the Doppler flow profile across the mitral valve and also to be noted are the 2D features of LA and LV for associated abnormality like LVH, LAE etc.
Why diastolic dysfunction assessment difficult in AF ?
Since most diastolic doppler mitral inflow parameters involve analysis of atrial contraction A wave, atrial fibrillation makes it difficult to assess diastolic dysfunction. Since we have only early diastolic velocity to assess, the changes confined to this E velocity is of paramount importance. This E velocity again is subjected to cycle length dependent alteration in both its acceleration and deceleration time , making things still more complex.
However, the following features help diagnose diastolic dysfunction in AF
- Lack of significant E velocity variation (<20%) Inspite of significant RR interval change.(This implies mean LAP is kept high irrespective of cycle length suggesting elevated baseline LAP)
- E deceleration time (<140ms) (In long cycle)
- Propagation velocity in color M Mode(Vp) <45cm/sec might help (RR interval dependent, measure in the long cycle)
- E/e” in a single beat by dual doppler probe (Ref 1) > 10 indicate diastolic dysfunction that correlate with PCWP> 15mmhg (Ref 1)
- Finally (and curiously ) presence of AF by itself may imply significant LV diastolic dysfunction. It could be due to an increase in atrial strain and afterload of LA (ie pre A-LVEDP) (Of course, It should be in the absence of mitral valve disease)
- LA dimension in AF*
*LA dimension is a very good sign of chronic elevation of LAP and diastolic dysfunction in the absence of mitral valve disease. However, AF can dilate the LA making it a less useful parameter. But, it should be noted in AF both RA and LA dilate together.So, a disproportionate LA>RA (or if RA is normal size ) could still be a marker of baseline LV diastolic dysfunction.
- Kusunose K., Yamada H., Nishio S., et al. Clinical utility of single-beat E/e′ obtained by simultaneous recording of flow and tissue Doppler velocities in atrial fibrillation with preserved systolic function. J Am Coll Cardiol Img 2009 2:1147–1156