TY - CHAP
M1 - Book, Section
TI - Measurements and Calculations
A1 - Mathew, Joseph P.
A1 - Nicoara, Alina
A1 - Ayoub, Chakib M.
A1 - Swaminathan, Madhav
PY - 2018
T2 - Clinical Manual and Review of Transesophageal Echocardiography, 3e
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)
SN -
PB - McGraw-Hill Education
CY - New York, NY
Y2 - 2023/03/20
UR - accessanesthesiology.mhmedical.com/content.aspx?aid=1171728658
ER -