Echocardiographic Tissue Characterization Demonstrates Differences in the Left and Right Sides of the Ventricular Septum

Abstract

The left and right ventricular function of the heart are influenced by the complex structure of the ventricular septum. The cyclic variation of ultrasonic backscatter over the cardiac cycle is known to be sensitive to both structural and functional characteristics of the myocardium. The objective of this study was to investigate differences in the measured magnitude and normalized delay of cyclic variation between the left and right sides of the ventricular septum in normal adult subjects (N=31). The measured mean magnitudes of cyclic variation were found to be 4.9 ± 0.4 dB and 2.4 ± 0.3 dB (mean ± SE; p < 0.0001) and the corresponding normalized delay values were found to be 0.94 ± 0.05 and 1.59 ± 0.12 (mean ± SE; p < 0.0001) for the left and right sides, respectively. These results show significant differences in the measured magnitude and normalized delay of cyclic variation between the left and right sides of the ventricular septum in normal subjects that appear consistent with predictions based on previously described models of cyclic variation of backscatter and reported measurements of transmural differences in strain properties of the septum.

Assessment of the Helical Ventricular Myocardial Band Using Standard Echocardiography

“…It is necessary to determine a rational means of segmental differentiation. Several investigations demonstrated that the echogenic reflection arises when insonification is perpendicular to the predominant myofiber orientation, and disappears for parallel insonification . Our study also showed that different acquisition angles had influence on the reflection.…”

“…Several investigations demonstrated that the echogenic reflection arises when insonification is perpendicular to the predominant myofiber orientation, and disappears for parallel insonification. 20,21 Our study also showed that different acquisition angles had influence on the reflection. Second, because speckle tracking uses a pattern-matching algorithm, errors in early frames can become amplified through subsequent frames.…”

Will the real ventricular architecture please stand up?

“…; Holland et al. ) in which lengthening begins first in the left ventricular side (right‐handed helix). This lengthening begins before aortic valve closure.…”

The helical ventricular myocardial band—or what's in a name?

“…These observations have been made by sonomicrometry 21 and by different modalities of F I G U R E 1 Five models of strips | 1449 Editorial echocardiography. [22][23][24] Therefore, even without anatomic evidence of separate muscle bands, there are two functional groups of muscle fibers.…”

“…The left ventricular side of the septum (right‐handed helix) contracts about 60–90 ms and relaxes about 60–90 ms before the left‐handed helix on the right ventricular side of the septum. These observations have been made by sonomicrometry and by different modalities of echocardiography . Therefore, even without anatomic evidence of separate muscle bands, there are two functional groups of muscle fibers.…”