Abstract 19169: Is Left Ventricular Twisting Obtained Using Three-dimensional Ultrasound Speckle Tracking Imaging Useful in Assessing Left Ventricular Function?-Comparison with Invasive Parameters
Background: During systole the left ventricle (LV) presents an opposite rotation between the apical and the basal levels, that is, LV twisting. A novel 3-dimensional ultrasound speckle tracking imaging (3D-STI) enables us to evaluate these motions simultaneously. We investigated whether LV twisting or untwisting had relations with invasively obtained LV systolic and early diastolic function parameters.
Methods: Study subjects consisted of consecutive 27 patients who underwent diagnostic cardiac catheterization and echocardiographic examination simultaneously. We acquired 3D images (Artida, Toshiba) at rest lying in the supine position with recording LV pressure simultaneously during cardiac catheterization. Frame rate ranged was from 30 to 35 frames per second. Seven of them were excluded from analyses due to insufficient image quality. The twisting of LV was calculated by a newly developed software (Ultra-Extend, Toshiba). Twisting of LV was expressed in degrees, negative if clockwise and positive if counterclockwise. Peak twisting during systole was obtained as the difference between apical and basal rotation. Amplitude of untwisting during early diastole was also calculated. From the recorded pressure waves in cardiac catheterization, both peak positive and negative dP/dt were determined and then the time constant τ of LV isovolumic relaxation was also calculated.
Results: Peak twisting during systole significantly correlated with both negative dP/dt (r=0.76, p<0.0001) and the time constant τ (r=−0.74, p<0.0001). Amplitude of untwisting during early diastole also significantly correlated with both peak negative dP/dt (r=0.72, p<0.0001) and the time constant τ (r=−0.60, p<0.0001).
Conclusions: These findings indicate that LV relaxation is related not only to the amplitude of LV untwisting during early diastole but also to the peak LV twisting during systole. Twisting of LV plays a crucial role in producing LV elastic recoil and is closely related to LV relaxation.
- © 2010 by American Heart Association, Inc.