[Standard contraction curves of the left ventricle for the objective quantification of segmental kinetics]

Two left ventricle angiographically-standard contraction curves are proposed: one for the 30-degree right anterior oblique (RAO) projection, and the other for the 60-degree left anterior oblique (LAO) projection. These curves are obtained by a calculation which uses the end-diastolic and end-systolic silhouettes along with the longitudinal axes. The best calculation method, which is different in the two projections, has been identified by computer testing of a number of hypothesis over a "normal" population of 18 pairs of RAO and 7 pairs of LAO silhouettes. The working hypothesis was selected by minimizing the standard deviation. In both projections the percent reduction of 20 areas is performed. The 20 RAO areas are defined by 10 equidistant orthogonal coordinates which intersect the longitudinal axis; moreover, the longitudinal axis "angiographic shortening", becomes divided into "cavity real shortening" and "apical parietal effacement'. The 20 LAO areas are defined by radial axes spaced by 15 degree intervals. The proposed standard curves show a low standard deviation of the calculated points: mean 7.8% +/- 3.68 (SD) for the RAO curve, and mean 9.8% +/- 3.68 for the LAO curve. These curves achieve the goal of a standard reference for the objective evaluation of the left ventricle segmentary contraction analysis.