RT Book, Section A1 Mathew, Joseph P. A1 Swaminathan, Madhav A1 Ayoub, Chakib M. SR Print(0) ID 6922062 T1 Appendix E. Measurements and Calculations T2 Clinical Manual and Review of Transesophageal Echocardiography, 2e YR 2010 FD 2010 PB The McGraw-Hill Companies PP New York, NY SN 978-0-07-163476-2 LK accessanesthesiology.mhmedical.com/content.aspx?aid=6922062 RD 2022/05/23 AB Fractional shortening (%) =Velocity of circumferential fiber shortening (circ/sec) =fractional shortening × ejection timeFractional area change (%) =Ejection fraction (%) =Volume by Simpson's method of disks where the LV is modeled as a series of stacked cylindrical disks capped by an elliptical disk apexVolumecylindrical disks = (π × D1/2) × D2/2) × Hwhere D1 and D2 are orthogonal diameters of the cylinder, and H is the height of the cylinderandVolumeelliptical disk = Ah/2 + a2/b2 × π × h3/6where 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 acylinder–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) =Meriodinal wall stresswhere 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 stresswhere L represents the LV long-axis lengthStrain (%) =where length0 is the initial lengthStrain rate (s–1) =LV mass (g) =(1.04 × [(LVID + PWT + IVST)3 – LVID3]) × 0.8 + 0.6dP/dt (mm Hg/s) =32 × 1000/dtwhere dt (in msec) is the time for velocity to rise from 1 m/s to 3 m/s on a continuous wave Doppler tracing of mitral regurgitationMyocardial performance index =