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Dr. Vittorio Dall'Aglio - Medico Chirurgo specialista in Cardiologia - Pordenone
 

Overview and choice of parameters to assess regional ventricular function: the semiquantitative approach


GIAN LUIGI NICOLOSI,VITTORIO DALL’AGLIO, CHIARA LESTUZZI,RENATA MIMO,DANIELA PAVAN, DOMENICO ZANUTTINI

Cardiologia, Ospedale Civile, 33170 Pordenone, Italy


© 1990 Elsevier Science Published B.V. (Biomedical Division)
Echocardiography 1990
A. Dagianti and H. Feigenbaum, editors

Ischemic heart disease and several other cardiac disorders are associated with regional abnormalities in ventricular structure and function.
Two-dimensional echocardiography, because of its characteristics of spatial and temporal resolution, is a real-time tomographic technique especially suitable for regional analysis of left ventricular wall abnormalities, either structural and functional [1-6].
In current clinical practice, a semi quantitative method that derives wait motion score based on a visual impression of regional wall motion is commonly utilized [1-6]. Several studies using a variety of segmental divisions and different methods of analysis of wall motion have been published [1-6].

REPORTED METHODS

The reported methods divide the base-apex length (long axis) of the left ventricle into three nearly equally spaced thirds.These three levels are basal, mid and apical. The basal region lies between the reference line drawn through the base of the heart and a line drawn through the tips of the left ventricular papillary muscles. The mid region lies between a line drawn through the most caudal portion of the base of the papillary muscles and a line drawn through the tips of the papillary muscles. The apical region lies between a line drawn through the tip of the cardiac apex and a line drawn through the most caudal portion of the base of the papillary muscles [1-6].
Using short-axis planes through the mid-portion of each of the three long-axis regions, the left ventricular free wall and the ventricular septum can be further subdivided. The basal and the mid region can be subdivided into 5, 6 or 8 segments. The apical region can be considered as a single segment or subdivided into 4 segments. These different classifications leads to an 11 segment model [3], a 14 segment model [1], a 16 segment model [5], a 20 segment model [4].

ADVANTAGES AND DISADVANTAGES OF THESE CLASSIFICATIONS

Each of these classifications has advantages and disadvantages. All these classification systems [1,3,4,5] are compatible with anatomic data which indicate that the ventricular septum forms approximately 40% of the circumference of the left ventricle [1]. All allows easy identification of the segments using internal anatomic landmarks [1,3,4,5].
The ventricular segments tend to correlate well with common patterns of coronary arterial distribution [1]. However, myocardial regions will almost never correlate precisely with coronary blood flow,because the patterns of coronary distribution are so highly variable [1].Furthermore any given myocardial region may, in some person, receive its blood supply from the branches of two independent major epicardial arteries [1].
Classification models which subdivide the left ventricle into an even number of myocardial segments around the short-axis [4,5] are such that every myocardial wall segment has a complimentary myocardial segment exactly opposite (i.e.180 degrees) from it. This feature is particularly useful when comparing myocardial wall segments identified with two-dimensional echocardiography to shadow-graphic images of the left ventricle such as those obtained with contrast ventriculography, radionuclide cineangiography or thallium scintigraphy [4].
By subdividing the left ventricle into a larger number of segments around the short-axis, functional abnormalities can be described more clearly and precisely. This leads to a better correlation with generally employed anatomic and electrocardiographic terms [4,5].
Classifications with lower number of segments tend to overestimate the percent age of dissynergic areas. Classifications with higher number of segments, on the other hand, usually require longer training and can be more difficult to apply [5,6]. Left ventricular apex, however, should be probably considered as a 4 segment region, because it can be very frequently only partially involved by the dissynergy [1,4,5,6].

SCORING SCHEMES FOR REGIONAL WALL MOTION ABNORMALITIES

Another area that has been the source of confusion pertains to the different scoring schemes for regional wall motion abnormalities.
One scoring scale has assigned to normally contracting segment the score of 0,
hypokinesis 1, akinesis 2, diskinesis 3, hyperkinesis -1 [2].
More recently a different scoring scale has been suggested assigning to normally contracting segments (or hyperkinetic segment) the score of 1, hypokinesis 2, akinesis 3, diskinesis 4, and aneurysmal (that is diastotically deformed) segment 5 [5].
A wall motion score index can be derived representing the sum of all scores divided by the number of segments visualized [5]. For this index to be reliable and meaningful it is important that all or nearly all segments be visualized [5]. The percent of abnormally and/or percent of normally contracting myocardium can also be calculated. It must be realized, however, that the percent of abnormally contracting myocardium should not be equated with the percent of infarcted myocardium.

EVALUATION OF MYOCARDIAL WALL SEGMENTS

Both motion and thickening of myocardial wall should be evaluated for each segment [2]. To obtain adequate visualization of motion and thickening of each wall segment a complete and extensive echocardiographic examination should be always obtained by using parasternal, apical and subcostal approaches.All longitudinal, cross-sectional, 4 chamber and intermediate off-axis views, which can be useful for adequate visualization of anatomy and function of different myocardial walls, should be adequately explored.
Wall motion and thickening should be analyzed by using real-time, slow-motion and frame by frame evaluation of two-dimensional images, either by videotape or computer assisted.

CONCLUSIONS

In conclusion two-dimensional echocardiography allows identification and definition of site and extension of regional wall abnormalities, either structural or functional.
Complete and extensive examination should be performed in order to achieve adequate visualization of each segment from different views and approaches.
Wall motion abnormalities should be defined both for motion and thickening of myocardial wall.
Complete examinations and adequate standardization should allow precise eva-
Illation of myocardial segments in the majority of patients.

REFERENCES

1. Edwards WD, Tajik AJ, Seward JB (1981) Standardized nomenclature and anatomic basis for regional tomographic analysis of the heart. Mayo Clin Proc 56:479-497

2. Kotler MN, Goldrnan AP, Parameswaran R, Parry WR (1986) Acute consequences and chronic complications of acute myocardial infarction.Echocardiography 3:295-317

3. Marino P , Zanolla L, Zardini P (1989) Effect of streptokinase on left ventricular modeling and function after myocardial infarction:the GISSI (Gruppo Italiano per lo Studio della Streptochinasi nell’Infarto miocardico) Trial. J Am Coil Cardiol 14:1149-1158

4. Henry WL, DeMaria A, Feigenbaum H, Kerber R, Kisslo J, Weyinan AE, Nanda N, Popp RL, Sahn D, Schiller NB, Tajik AJ (1982) Report of the American Society of Echocardiography Committee on nomenclature and standards: identification of myocardial wall segments. American Society of Echocardiography, Duke University Medical Center, PO Box 3840, Durham, North Carolina 27710,USA

5. Schiller NB, Shah PM, Crawford M, DeMaria A, Devereux R, Feigenbaum H., Gutgesell H, Reichek N, Sahn D, Schnittger I, Silverman NH,Tajik AJ (1989) Recommendations for quantitation of the left ventricle by two-dimensional echocardiography. J Am Soc Echo 2:358-367

6. Nicolosi GL, Zannini L, Facchin L (1987) Sede ed estensione dell’ischemia miocardica acuta:diagnosi ecocardiografica. In: Caturelli G (ed) Cura Intensiva Cardiologica 1987. Librex, Milano, pp 82-90

 

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