The Big Heart Disease Lie
Left Ventricle LVIDd
Fig. 3. Two-dimensional-guided M-mode measurements and derived indices. M-mode is simple, reproducible, and accurate when ventricular geometry is normal. It provides good endocardial resolution. The ejection fraction (EF, Teich) is an automated calculation based on the Teichholz method (see Table 4).
Fig. 3. Two-dimensional-guided M-mode measurements and derived indices. M-mode is simple, reproducible, and accurate when ventricular geometry is normal. It provides good endocardial resolution. The ejection fraction (EF, Teich) is an automated calculation based on the Teichholz method (see Table 4).
Diameter 1
Diameter 1
Fig. 4. Prolate ellipsoid. One geometric model used to calculate left ventricular volumes from on M-mode measurements assumes an elliposoid shape for the left ventricle. This model uses diameters (D) and length to calculate areas and volumes. A hemi-ellipsoid model is preferred in left ventricular volumetric and mass quantification using two-dimensional echocardiography (Figs. 13 and 15).
Fig. 4. Prolate ellipsoid. One geometric model used to calculate left ventricular volumes from on M-mode measurements assumes an elliposoid shape for the left ventricle. This model uses diameters (D) and length to calculate areas and volumes. A hemi-ellipsoid model is preferred in left ventricular volumetric and mass quantification using two-dimensional echocardiography (Figs. 13 and 15).
lv volumes and ef by m-mode
Estimates of LV volumes and EF by M-mode rely on geometrical assumptions of LV morphology. The simplest formula cubes the LVIDd. Another calculates volume using the formula for a prolate ellipsoid (Fig. 4). These measures become even more inaccurate when applied to dilated ventricles. The Teichholz method (Table 4) is commonly used to calculate ventricular volumes from M-mode measurements (from which EF can be calculated). However, this method is only recommended when ventricular geometry is relatively normal (see Chapter 3, Fig. 14D). Specifically, in patients with myocardial infarction involving the apex, M-mode measurements, which are obtained at the base of the heart, will underestimate ventricular size and overestimate ventricular function.
lv parameters by 2d echocardiography
2D echocardiography is the primary modality used for qualitative and quantitative assessment of ventricular systolic performance (Table 5). In postmyocardial infarction and heart failure patients, 2D echo has great utility in their management and risk stratification. An inverse relationship exists between cardiovascular morbidity, mortality, and LV systolic functionâ€”specifically LVEF. EF, however, is not the only predictor of survival in patients with advanced heart failure.
limitations of 2d assessment of lv systolic function
2D echocardiography is not a true tomographic technique (like cardiac computed tomography or cardiac magnetic resonance imaging). Off-axis measurements,
Table 5
Two-Dimensional Parameters in Left Ventricular Function
Qualitative/semi-quantitative parameters
Quantitative parameters
Global function: ventricular wall motion and thickening
RWM assessment
Visual estimation of ejection fraction
Longitudinal ventricular shortening
Mitral annular motion
Left ventricular wall dimensions:
Wall thickness Internal diameters: LVIDd, LVIDs
MWFS: from linear measures of diastolic and systolic cavity sizes and wall thickenesses:
Inner shell = ([LVIDd + SWTd/2 + PWTd/2 ]3 - LVIDd3 + LVIDs3) 1/3 - LVIDs
([LVIDd + SWTd/2 + PWTd/2] - [LVIDs + inner shell])
Left ventricular quantification
Biplane method of discs (modified Simpson's rule) Multiple diameter method Others based on assumptions for left ventricular geometry, e.g., cylinder-hemiellipse, biplane ellipsoid, hemisphere-cylinder, bullet, models
Left ventricular ejection fraction (%) = [(EDV - ESV)/EDV] x 100% Left ventricular mass (MassLV) = 0.8 x [1.04 (LVIDd + PWTd +
SWTd)3 - (LVIDd)3] + 0.6 g Left ventricular wall stress (a) Meridional wall stress Circumferential
Table modified from Recommendations for Chamber Quantification. American Society of Echocardiography, 2005. RWM, regional wall motion; LVIDd, left ventricular internal diameter at end diastole; LVIDs, left ventricular internal diameter at end systole; MWFS, mid-wall fractional shortening; SWTd, septal wall thickness; PWTd, posterior wall thickness; EDV, end diastolic volume; ESV, end systolic volume; FS, fractional shortening.
Table modified from Recommendations for Chamber Quantification. American Society of Echocardiography, 2005. RWM, regional wall motion; LVIDd, left ventricular internal diameter at end diastole; LVIDs, left ventricular internal diameter at end systole; MWFS, mid-wall fractional shortening; SWTd, septal wall thickness; PWTd, posterior wall thickness; EDV, end diastolic volume; ESV, end systolic volume; FS, fractional shortening.
Fig. 5. Left ventricular foreshortening. Foreshortening (shown right) occurs when the imaging plane does not transect the center of left ventricular apex (left). It is a common source of error in left ventricular quantification in two-dimensional echocardiography. (Please see companion DVD for corresponding video.)
Fig. 5. Left ventricular foreshortening. Foreshortening (shown right) occurs when the imaging plane does not transect the center of left ventricular apex (left). It is a common source of error in left ventricular quantification in two-dimensional echocardiography. (Please see companion DVD for corresponding video.)
e.g., foreshortening, easily occur (Fig. 5; please see companion DVD for corresponding video). Distortions of LV geometry seen in patients with ischemic heart disease pose challenges to 2D assessment (Figs. 1A,B and 6).
qualitative and semi-quantitative measures of lv systolic function
Making linear measurements of cardiac chamber dimensions by 2D echo follows the principles outlined
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