Dynamic analysis of left-ventricular shape based on curvature function.

Abstract

The local curvature function is defined as the change in curvature around the circumference of the LV silhouette. The local instantaneous curvature function is used here to quantify regional left-ventricular (LV) performance throughout the cardiac cycle. Left ventriculography images, taken in the right anterior oblique (RAO) view from nine patients with normal ventricular contraction, and eight patients with anterior hypokinesis (AHK) are used. The local curvature around the circumference of the LV is calculated for each heart throughout the ejection period. The dynamic increase in the curvature of the apex, defined as apical sharpening, is a typical feature of LV contraction. Apical sharpening from end-diastole to end-systole is closely related to the degree of hypokinesis. Normal hearts show larger apical sharpening (128 +/- 57%, SD) than do AHK hearts (46 +/- 13%, p = 0.002). The ratio between apical and anterior curvatures at ES has been found to be 7 +/- 3.5 for normal hearts and 2.3 +/- 0.6 for AHK hearts (p = 0.003). Linear regression between the ventricular volume and apical curvature yields a significant relationship for the normal hearts (r = 0.82 +/- 0.06, average p = 0.07), but not for the AHK hearts (r = 0.72 +/- 0.2, average p = 0.24). Thus, the information inherent in the local curvature of the LV and its dynamic change throughout the cardiac cycle may be used to distinguish between normal and anterior hypokinetic hearts.