Abstract 18157: Can 3-Dimensional Left Atrial Endocardial Surface Area Tracking Method Be Applied to the Evaluation of Left Atrial Reservoir Function?

Abstract

Background: Three-dimensional wall motion tracking (3D-WMT, Toshiba) is a newly developed technique that enables us to evaluate left atrial (LA) endocardial surface area deformation, which is named area change ratio (ACR). The peak LA-ACR was obtained at LV end-systole; our hypothesis, therefore, was that peak LA-ACR had relations to not only LV systolic function but also LV early diastolic function. We investigated this issue in comparison with invasively obtained parameters of LV systolic and diastolic function.

Methods: Study subjects were consecutive 37 patients with sinus rhythm who underwent diagnostic cardiac catheterization and 3D-WMT on the same day. Seven of them had prior myocardial infarction, while the remaining 30 had no localized LV wall motion abnormality. The temporal change of LA-ACR was drawn offline using an echo image analyzer (Ultra-Extend, Toshiba). Initial frame was set at LV end diastole, and then the peak LA-ACR at LV end-systole was calculated. LV pressure was obtained using a catheter-tipped micromanometer, and then left ventriculography was perfumed. From the recorded pressure waves, both peak positive and negative dP/dt values were determined, and then the time constant τ of LV isovolumic relaxation was also computed. LV volumes were calculated from left ventriculography. LV end-systolic volume was indexed to body surface area (LVESVI).

Results: The peak LA-ACR had significant positive correlations with both peak positive dP/dt (r=0.56, p<0.001) and LVESVI (r=-0.70, p<0.0001). Furthermore, the peak LA-ACR had also inverse correlations with both peak negative dP/dt (r=-0.51, p<0.01) and the time constant τ of LV isovolumic relaxation (r=-0.75, p<0.0001).

Conclusion: This study indicates that peak LA-ACR reflects LV behavior from LV end systole to early diastole, suggesting the LA-ACR can be used as a parameter of the LA reservoir function.