Abstract 18095: Left Atrial Endocardial Surface Area Change Ratio Assessed by 3-Dimensional Wall Motion Tracking is a Useful Method in Assessing Left Ventricular End-Diastolic Pressure

Abstract

Background: Several previous studies reported that left atrial (LA) volume is a useful parameter of left ventricular (LV) diastolic dysfunction. One can evaluate LA volume (LAV) more easily and precisely using recently developed 3-dimensional (3D) ultrasound imaging technique in clinical settings. Furthermore, 3D wall motion tracking (3D-WMT, Toshiba) enables us to evaluate not only LA volumes but also LA endocardial surface area deformation, which is named area change ratio (ACR), simultaneously. We investigated whether the LA-ACR was superior to other parameters of the LA obtained by 3D imaging in the evaluation of LV diastolic function.

Methods: Study subjects were consecutive 37 patients with sinus rhythm who underwent diagnostic cardiac catheterization and 3D ultrasound imaging on the same day. Seven of them had prior myocardial infarction, while the remaining 30 had no localized LV wall motion abnormality. The temporal changes of both the LA-ACR and LA volume were 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. Maximal LA volume indexed to body surface area (max-LAVI) and LA emptying fraction (LAEF) were also calculated. LAEF was defined as (maximal LA volume - minimal LA volume)/maximal LA volume. LV pressure was obtained using a catheter-tipped micromanometer. From the recorded pressure waves, we computed mean LV diastolic pressure (m-LVDP) and LV end-diastolic pressure (LVEDP).

Results: The max-LAVI had weak but significant correlations with both LVEDP (r=0.44, p<0.01) and m-LVDP (r=0.45, p<0.01). The LAEF also had weak but significant correlations with both LVEDP (r=-0.45, p<0.01) and m-LVDP (r=-0.46, p<0.01). The peak LA-ACR at LV end-systole had significant and much closer correlations with both the m-LVDP (r=-0.68, p<0.001) and the LVEDP (r=-0.72, p<0.0001).

Conclusion: This study indicates that the LA endocardial surface area change ratio obtained using 3D-STI is superior to the parameters derived from LA volume change in the assessment of LV chamber stiffness. LA wall area change ratio is a new useful parameter for noninvasive prediction of m-LVDP and LVEDP.