Assessment of Two‐Component Ventricular Septum: Functional Differences in Systolic Deformation and Rotation Assessed by Speckle Tracking Imaging

BACKGROUND: The purpose of this study was to elucidate functional differences in the right and left components of the ventricular septum (Rt and Lt, respectively). METHODS: Strain, strain rate, rotation, and rotation rate profile curves of Rt and Lt were obtained using speckle tracking echocardiography in 38 normal children and adolescents. RESULTS: The echogenic bright line serving as the boundary separating Rt from Lt was consistently visible in the middle of the ventricular septum. There was no significant difference in peak strain or peak strain rate during systole between Rt and Lt. However, the time interval from the onset of QRS-wave to peak strain and peak strain rate were significantly lower in Lt than in Rt in terms of radial and circumferential deformation (P < 0.005, all), whereas there was no significant difference in longitudinal deformation in the time to peak strain or peak strain rate between Rt and Lt. Lt showed counterclockwise rotation, whereas Rt showed clockwise rotation (10.4 ± 2.9° vs. -10.2 ± 2.6°, P < 0.0001). Time to peak rotation was significantly lower in Lt than in Rt (201.7 ± 32.7 msec vs. 370.4 ± 31.2 msec, P < 0.0001). CONCLUSION: Morphologically and functionally the ventricular septum is a two-component structure. Evaluation of deformation and rotation of the 2 components would help in evaluating septal performance.