Regional sequential motion in the normal left ventricle: nonuniform apical motion.

Timing of the onset and sequence of systolic regional wall motion was examined in the digitized left ventricular cineangiograms of 13 patients with angiographically normal coronary arteries and left ventricular function. Distance--time curves for anterior and inferior wall segments, the aortic valve plane, and apex point were compared to the volume--time curve in each ventricle. No significant differences were found in the onset of motion for the wall segments or for descent of the aortic valve where the sequence of motion was generally uniform. At the apex point, however, the onset of motion was significantly delayed. In addition, reduced velocity of motion in the first half of systole was followed by high velocity motion in the latter half. This apparent nonuniform apical motion may be explained by a geometric relationship of normally contracting myocardial wall fibers adjacent to a thin apical point which has relatively little or no contractile motion of its own.