RT Book, Section
A1 Mathew, Joseph P.
A1 Nicoara, Alina
A1 Ayoub, Chakib M.
A1 Swaminathan, Madhav
SR Print(0)
ID 1158274401
T1 Measurements and Calculations
T2 Clinical Manual and Review of Transesophageal Echocardiography, 3e
YR 2018
FD 2018
PB McGraw-Hill Education
PP New York, NY
SN 9780071830218
LK accessanesthesiology.mhmedical.com/content.aspx?aid=1158274401
RD 2020/02/25
AB Fractional shortening(%)=(end-diastolic diameter)−(end-systolic diameter)(end-diastolic diameter)×100Velocity of circumferential fiber shortening (circ/s) = fractional shortening ×1/ ejection timeFractional area change(%)=(end-diastolic area)−(end-systolic area)(end-diastolic area)×100Fractional area change corrected for afterload(FAC afterload corrected(FACac)=FAC×log([MAP-RAP]/CI)×100%)Ejection fraction(%)=(end-diastolic volume)−(end-systolic volume)(end-diastolic volume)×100Volume by Simpson method of disks where the LV is modeled as a series of stacked cylindrical disks capped by an elliptical disk apex Volumecylindrical disks=(π×D12)×D22)×Hwhere D1 and D2 are orthogonal diameters of the cylinder, and H is the height of the cylinderandVolumeelliptical disk=Ah2+a2b2×π×h36where A is the area of the ellipsoid segment, h is the height of the ellipsoid segment, and a and b are radii of the total ellipsoid.Volume by the area-length method where the LV is modeled as a cylinder–hemi-ellipsoidVolume=(5×area×major-axis length)6where the area is planimetered by using a short-axis view at the level of the mitral valveVolume by the diameter-length method where the LV is modeled as a prolate-ellipsoidVolume=(π×D1×D2×major-axis length)6where D1 and D2 are orthogonal short-axis diametersStroke volume (ml) = (end-diastolic volume – end-systolic volume)Cardiac output (liters/min) = (stroke volume × heart rate)Cardiac index (liters/min/m2) =(stroke volume×heart ratebody surface area)Meriodinal wall stressσm=1.33×P(Ac/Am)×103dyne/cm2where P represents LV peak pressure, Ac is LV cavity area, and Am represents LV myocardial area (area of the muscle in the short-axis view)Circumferential wall stressσc=[(1.33PAc)(Am+Ac−Ac)]×[4AcAc/πL2(Am+Ac−Ac)]dyne/cm2where L represents the LV long-axis lengthPreload-Adjusted Maximal Power index =Integrated Area within Pressure-Area Loop(End-Diastolic Area)3/2Strain (%) =length−length0length0where length0 is the initial lengthStrain rate (s−1) =straintimeStrain Rate≅Velocitya−VelocitybDistanceLV mass (g) = (1.04×[(LVID+PWT+IVST)3−LVID3])×0.8+0.6 gdP/dt (mm Hg/s) = 32 × 1000/dtwhere dt (in ms) is the time for velocity to rise from 1 to 3 m/s on a continuous-wave Doppler tracing of mitral regurgitationMyocardial performance index =(isovolumic contraction time+isovolumic relaxation time)(ejection time)