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

Area of Science:

• Cardiovascular Physiology
• Cardiac Imaging
• Biomechanical Analysis

Background:

• Understanding the precise timing and sequence of regional myocardial contraction is crucial for assessing left ventricular function.
• Digitized left ventricular cineangiography provides detailed insights into cardiac mechanics.
• Previous studies have established general patterns of systolic motion, but apical dynamics warrant further investigation.

Purpose of the Study:

• To examine the timing and sequence of systolic regional wall motion in patients with normal coronary arteries and left ventricular function.
• To compare the motion patterns of anterior and inferior wall segments, the aortic valve plane, and the apex with ventricular volume changes.

Main Methods:

• Analysis of digitized left ventricular cineangiograms from 13 patients with normal coronary arteries and ventricular function.
• Generation of distance-time curves for anterior and inferior wall segments, aortic valve plane, and apex.
• Comparison of these curves with the volume-time curve of each ventricle.

Main Results:

• No significant differences were observed in the onset of motion for anterior and inferior wall segments or the descent of the aortic valve plane.
• The sequence of motion for these segments and the aortic valve plane was generally uniform.
• A significant delay in the onset of motion was noted at the apex, with reduced velocity in early systole followed by increased velocity in late systole.

Conclusions:

• The apex exhibits a distinct pattern of delayed and altered velocity systolic motion compared to other ventricular regions.
• This non-uniform apical motion is likely attributable to the geometric configuration of myocardial fibers and the apex's intrinsic contractile properties.
• These findings contribute to a more nuanced understanding of normal left ventricular mechanics.