Left Ventricular Remodeling

The Big Heart Disease Lie

Cure for Cardiovascular Disease Found

Get Instant Access

Gross Lvef

Fig. 6. Three-dimensional (3D) images showing gross distortion of left ventricular geometry post-myocardial infarction. 3D representation of progressive remodeling of the left ventricle in a patient with a large anterior-apical myocardial infarction. Note the progressive distortion of the ventricular geometry with time (A-C).

Fig. 6. Three-dimensional (3D) images showing gross distortion of left ventricular geometry post-myocardial infarction. 3D representation of progressive remodeling of the left ventricle in a patient with a large anterior-apical myocardial infarction. Note the progressive distortion of the ventricular geometry with time (A-C).

using M-mode described earlier (see also Chapter 3, Fig. 16). "Eyeball" estimates of LVEF are routinely used in clinical practice, but interobserver variability is high, and should be "calibrated" by quantitative measurements.

Accurate assessment of ventricular wall movements during the cardiac cycle is dependent on image quality. Optimal image acquisition is influenced by patient characteristics, operator skill, and instrument settings. Proper patient positioning helps to optimize imaging of parasternal and apical views (Chapter 3, Fig. 9). Images are best acquired at end-expiration or during quiet respiration.

Failure to accurately visualize the endocardial border introduces uncertainty into 2D measurements. To minimize this, techniques to improve endocardial border definition, e.g., harmonic imaging, B-color imaging, LV opacification with contrast agents, and Doppler based techniques are often employed (Figs. 7 A,B and 8; please see companion DVD for corresponding video).

qualitative grades of lv systolic function

Normal ventricular walls thicken during systole—a manifestation of myocardial fiber shortening—as both ventricles contract. Ventricular systolic contraction is accompanied by a reduction in ventricular cavity size and can be qualitatively assessed as normal, reduced, or hyperdynamic (Fig. 9). Normally, 60-70% of ventricular end-diastolic volume is ejected during each cardiac cycle.

Reduction of LV systolic function can be estimated to the nearest 5 or 10% by an experienced observer. EF of 55% or more is generally considered normal. EF between 40 and 55% is considered mildly reduced; EF between 30 and 40% is considered moderately reduced; EF less than 30% is considered severely reduced. Global reduction of systolic function is frequently accompanied by regional variation.

When the EF exceeds 70%, it is considered to be "hyperdynamic." EFs exceeding 75% manifest as near obliteration of ventricular cavity when viewed from the parasternal or apical windows. This can be seen in hypo-volemia or in patients with hypertrophic cardiomyopathy.

Estimations of EF by experienced sonographers correlates well with other quantitative measures of EF. It is, therefore, a practical first step in qualified hands.

grading regional wall motion

Regional LV wall motion assessment generally employs the 16-segment model recommended by the ASE (1989), or the more recent 17-segment model (which adds an additional region for the apex). Ventricular segment scores are assigned based on two qualitative measures of ventricular wall behavior during systole: (1) wall movement (contraction) and (2) wall thickening. Graded scores of contractility of the individual segments range from a normal score of 1 to the worst score of 5 (Figs. 1B and 10A; please see companion DVD for corresponding video for Fig. 8). The myocardium of a dysfunctional segment thickens less, or becomes thinner, during systole.

A segment that shows noticeable reduction in contractility is hypokinetic and assigned a score of 2. A segment that barely moves or thickens during systole is akinetic (score = 3). Dyskinetic myocardium moves paradoxically during systole (score = 4). Aneurysmal myocardium remains deformed during diastole. The integrated wall motion score is the sum of the scores divided by the number of scored segments. A wall score index of 1 indicates normality. Larger scores reflect more severe degrees of systolic dysfunction (Fig. 1B; please see companion DVD for corresponding video).

Was this article helpful?

0 0
Your Heart and Nutrition

Your Heart and Nutrition

Prevention is better than a cure. Learn how to cherish your heart by taking the necessary means to keep it pumping healthily and steadily through your life.

Get My Free Ebook


Post a comment