Info

metabolic syndrome, anemia

Table modified from Jessup M, Brozena S. Heart failure. N Engl J Med 2003;348:2007-2018.

Table modified from Jessup M, Brozena S. Heart failure. N Engl J Med 2003;348:2007-2018.

the long axis of the heart and immediately distal to the tips of the mitral valve leaflets in the parasternal long-axis view (Fig. 3).

Measurements are taken at end-diastole (d)—defined as the beginning of the QRS complex—but preferably using the at the widest LV cavity diameter, and at endsystole (s)—using the narrowest LV cavity diameter. The leading-edge convention of the ASE is the recommended method of measurement. The diastolic measurements obtained are the interventricular septal wall thickness, the LV internal diameter at end diastole (LVIDd) and posterior wall thickness. In systole, the LV systolic diameter (LVIDs) is measured (Fig. 3). Calculations of other indices of LV systolic function, e.g., LV ejection fraction (EF), volumes, and mass can then be performed (Table 4).

Table 4

M-Mode Parameters Used to Assess Left Ventricular Systolic Function

LVID (LVIDs < 3.7 cm; LVIDd < 5.6 cm are normal) Left ventricular WT

Percent change in WT = (WTs - WTd/WTs) Left ventricular volume Prolate ellipse calculation: volume= n/3 (LVIDd)3 Teichholz formula: volume = [7/(2.4 + LVIDd)] (LVIDd)3

Ejection fraction (EDV - ESV)/EDV

Fractional shortening (FS) (%) = (LVIDd - LVIDs)/LVIDd

Mitral valve E point—septal separation (normal > 7 mm)

Left ventricularmass (MassLV) = 0.8 x [1.04 (IVS + PWT + LVIDd)3 - LVIDd3] + 0.6 g

LVIDs, left ventricular internal diameter at end systole; LVIDd, left ventricular internal diameter at end diastole; WT, wall thickness; WTs, wall thickness at end systole; WTd, wall thickness at end diastole; EDV, end diastolic volume; ESV, end systolic volume; IVS, septal wall thickness, PWT, posterior wall thickness.

limitations of m-mode measurements

A common pitfall of M-mode measurements is the nonperpendicular alignment of the M-mode line in relation to the long axis of the LV. This leads to overes-timation of ventricular dimensions. Two-dimensional (2D)-guided M-mode measurements can aid proper alignment thereby minimizing error.

Another challenge is to accurately identify the endo-cardial and epicardial borders and avoid confusion with contiguous structures, e.g., chordae, trabeculations near the posterior wall, and false-tendons. The endocardial border is distinguished from ventricular trabeculations and chordae by its appearance as a continuous line of reflection throughout the cardiac cycle. The latter structures appear intermittently. The epicardium lies just anterior to the highly echo-reflective parietal pericardium (see Chapter 3, Figs. 13 and 14).

A major drawback of M-mode measurements is that these are valid only when LV geometry is normal. When LV geometry is abnormal, as in aneurysmal remodeling or in the presence of regional wall motion abnormality following myocardial infarction, M-mode measurements of heart size may be misleading. An exponential relationship exists between ventricular diameters and ventricular volumes. M-mode parameters, and indeed all other parameters of LV systolic function, are dependent on ventricular loading conditions.

End systolic Measurements

M-mode ivsd

LUI Del LVPWd LVIDs measurements used for calculations

1.05 cm

Was this article helpful?

0 0
How To Lose Your Belly Fat

How To Lose Your Belly Fat

Losing All that Excess Belly Fat and Getting a Well Toned Flat Stomach. Trimming down and toning up your entire body, from head to toe, is definitely something that many people want to do. But chances are, theres one place in particular where all that excess fat just doesnt want to seem to go away, no matter how hard you try.

Get My Free Ebook


Post a comment