06 PV loop

  • volume on bottom, pressure on top
  • right: take volume and pressure of each time and plot against one another
  • green: volume not changing, pressure go way up, isovolumic contraction. Both valves closed

  • top left point: end of systole
  • bottom right point: end of diastole
  • left line: end systolic pressure volume relationship, determined by myocardium characteristics. Adding/removing blood at end of systole moves along this line
  • right line: end diastolic pv relationship

  • MV closes at beginning of isovolumic contraction
  • pressure so high aortic valve opens
  • volume falls in LV, blood leaving

  • AV open, contraction
  • AV closes, isovolumic relaxation

  • MV opens

  • SV: difference between ESV and EDV, volume ejected
  • more afterload, higher pressure LV has to rise to overcome

Changes

  • hit left line sooner, at higher volume and pressure
  • harder to eject blood, eject less blood

  • contractility determines ESPVR
  • less contractility, less blood pushed out, more blood left behind

  • compliance determines preload
  • ventricle cannot fill and stiffer, higher pressure, lower volume

  • area: how much volume pumping x how much pressure generating

Pathology

  • higher afterload, lower SV, higher ESV

  • during isovolumic contraction, blood leak from LV to LA, falling

  • blood filling ventricle during relaxation

  • just slightly smaller