Assessment of Left Ventricular Function by Cardiac Ultrasound
James D. Thomas, MD* and
Zoran B. Popovi , MD, PhD
Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, Ohio
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Figure 1 Principle of the conservation of mass. Instantaneous flow through the shell outlined by the proximal isovelocity surface is identical to the regurgitation flow rate occurring through this insufficient mitral valve. To the right, the same valve shows a highly asymmetric regurgitation jet whose area underestimates the true amount of regurgitation.
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Figure 2 Principle of the conservation of energy. Decrease of cross-sectional area (as seen in aortic stenosis) leads to increase in velocity. Velocity increase leads to a pressure decrease distal to the stenosis.
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Figure 3 (A) Myocardial fiber and sheet orientation within a block of muscle excised from the anterior wall of the left ventricle. Myocytes lie in planes parallel to the long axis of the heart. Within these planes, myocyte orientation is circumferential at the mid-wall, but rotates clockwise (when viewed from the outside) to form a –60 degree left-handed helix in the epicardium (Epi) and counterclockwise to a +60° right-handed helix in endocardium (Endo). Myocytes are organized into sheets 4 cells thick that are stacked like shingles. (B) Myocardial sheet movement during cardiac cycle. During systole, due to rearrangement of myocytes, sheets are becoming more perpendicular toward the endocardium, thus helping to transform a 14% decrease in myocyte length to 40% thickening of the left ventricular wall.
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Figure 4 A dramatic difference between endocardial and epicardial shortening (quantitated by measurement of circumferential strains) of the septum and lateral wall in a normal left ventricle detected by speckle tracking imaging.
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Figure 5 (A) One-, 2-, and 3-dimensional representation of linear myocardial strains. (B) One-dimensional strain obtained by tissue Doppler imaging (TDI). (C) Two-dimensional strain obtained by speckle tracking imaging (STI). (D) A hypothetical strain that could be obtained by STI analysis of 3-dimensional data set.
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Figure 6 An example of the mismatch between high transmitral E-wave velocity (vmax; left) and flow propagation velocity (vp) occurring in a patient with a heart failure and elevated preload. PW = pulsed wave.
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Figure 7 A standard time/velocity map obtained by color M-mode (top); a time/pressure gradient map generated from color M-mode data by solving Euler equation (middle); and tracings of intraventricular pressure differences obtained by integration of time/pressure gradient map (bottom). E = peak early diastolic gradient obtained from left ventricular inflow; LV = left ventricular; LVOT = left ventricular outflow tract; S = peak systolic gradient obtained from the LVOT.
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Figure 9 Quantitation of torsion and torsion velocity (rate) by speckle tracking imaging. Images to the left represent cross-sectional views of the base and the apex of the left ventricle superimposed with speckle tracking imaging-generated markers of left ventricular torsion. Images to the right represent torsion rate and torsion signal. Arrowhead and arrow mark peak negative torsion velocity and peak systolic torsion, respectively.
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xy and torsion 
. Shear strain is generated by a contraction of epicardial fibers oriented in left-handed helix (light red arrow). Torsion is proportional to shear strain and ventricular length, and inversely proportional to short-axis radius.