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 =
