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Posts Tagged ‘Mconnell sign pulmonary embolism’

Mconnell’s  sign is a distinct echocardiographic sign that occurs in Acute pulmonary embolism , where RA and RV dilates. RV shows a distinct regional wall motion abnormality in which RV free wall shows akinesia (or severe hypokinesia ) with well-preserved RV apical contraction.This is visible in apical 4 chamber view.

This sign is explained by  both anatomic  and hemo-dyanmic reasons.

  • RV when exposed to  sudden pressure overload  it not only dilates , it’s wall stress increases (Laplace law : Wall tension = P x Radius  )   and end up mechanically stunned . But , since the RV has a complex shape the distribution of this stress  is not uniform .As the RV assumes more spherical  shape the apical  part is not exposed to this stress as it tend to abut under LV.
  • RV apex is anatomically tethered with LV apex and share significant amount of circumferential fibres .In patients with acute pulmonary embolism ,  LV usually is hyperkinteic  due to tachycardia .This pulls the  RV apex  along with it for a proxy contraction .
  • Rarely , primary RV ischemia  due to RCA under perfusion* may be responsible for this unique  wall motion defect . Since RV apex  is mostly supplied by LAD it is free from ischemia . (*Acute elevation of RV intramural pressure due to PHT , compromising RCA perfusion pressure  )

Reference

1.McConnell MV, Solomon SD, Rayan ME, Come PC, Goldhaber SZ, Lee RT. Regional right ventricular dysfunction detected by echocardiography in acute pulmonary embolism. Am J Cardiol. 1996; 78: 469–473.

2. Rachel P. SoslandKamal Gupta,McConnell’s Sign circulation. 2008; 118: e517-e518

3. Link to the Echo clipping of McConnell sign in echocardiography

 

 

 

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