Appendix E. Measurements and Calculations

Fractional shortening (%) =

Velocity of circumferential fiber shortening (circ/sec) =

fractional shortening × ejection time

Fractional 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 apex

Volumecylindrical disks = (π × D1/2) × D2/2) × H

where D1 and D2 are orthogonal diameters of the cylinder, and H is the height of the cylinder

and

Volumeelliptical disk = Ah/2 + a2/b2 × π × h3/6

where 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-ellipsoid

Volume = (5 × area × major-axis length)/6

where the area is planimetered by using a short-axis view at the level of the mitral valve

Volume by the diameter-length method where the LV is modeled as a prolate-ellipsoid

Volume = (π × D1 × D2 × major-axis length)/6

where D1 and D2 are orthogonal short-axis diameters

Stroke volume (ml) =

(end-diastolic volume – end-systolic volume)

Cardiac output (liters/min) = (stroke volume × heart rate)

Cardiac index (liters/min/m2) =

Meriodinal wall stress

where 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 stress

where L represents the LV long-axis length

Strain (%) =

where length0 is the initial length

Strain rate (s–1) =

LV mass (g) =

(1.04 × [(LVID + PWT + IVST)3 – LVID3]) × 0.8 + 0.6

dP/dt (mm Hg/s) =

32 × 1000/dt

where 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 regurgitation

Myocardial performance index =

Fractional area change (%) =

Ejection fraction (%) =

using Simpson's method of disks

Tricuspid annular plane systolic excursion (mm) From the transgastric RV inflow view and using M-mode, the movement of the leading edge of the lateral tricuspid annulus attachment is tracked during systole, and its excursion measured

Myocardial performance index =

dP/dt (mm Hg/s) =

12 × 1000/dt

where dt (in msec) is the time for velocity to rise from 1 m/s to 2 m/s on a continuous wave Doppler tracing of tricuspid regurgitation

Doppler shift

Δf = Difference between the transmitted frequency (ft) and received frequency

v = Velocity of red blood cells

θ = Angle between the Doppler beam and the direction of blood flow

c = Speed of ultrasound in blood (1540m/sec)

Stroke volume (ml) =

Stroke Distance × Cross Sectional Area (CSA)

where

Stroke Distance = LVOT or RVOT Velocity Time ...