Left atrial-left ventricular angle, a new measure of left atrial and left ventricular remodeling

Abstract

We assessed the left atrial-left ventricular (LA-LV) long axis angulation value as a new measure of LA remodeling, and studied its predictors, its effect on two-dimensional LA volume (2D LAVol) estimation, and optimization techniques for 2D LAVol values. Retrospective electrocardiogram-gated coronary computed tomographic angiograms of 164 consecutive patients were reviewed. The LA–LV angle was measured in reconstructed 3-chamber views, and its predictors were determined. The LAVol measured by the area-length method after image optimization along the LV long axis (AL) and the LA long axis (AC–AL), was compared with that measured by the three-dimensional (3D)-volumetric method. LAVol calculation was modified to minimize differences from the 3D values. LA–LV angles ranged from 0° to 63°. In the univariate analysis, decreasing angulation was significantly associated with increasing LV end-diastolic volume (LVEDV), mitral regurgitation grade, LV and LA anteroposterior dimensions, and decreasing LV ejection fraction (LVEF). On multivariate analysis, increasing LVEDV, MR, and LA anteroposterior dimension inversely correlated with angulation; LVEF was positively correlated. The AL and 3D methods significantly differed only for patients with angles ≤ 29.9°. Conversely, LAVol was overestimated for all angules by AC–AL. Modification of AL LAVol using a regression equation, or by substituting the shortest with the longest and average LA lengths in patients with angles ≤ 29.9° and 30–39.9°, respectively neutralized the difference. The LA–LV angle is a new measure of LA and LV remodeling predicted by LV size and function, MR, and LA-anteroposterior dimension. AL formula modifications based on angulation in LV-optimized views better correlate with the 3D method than LA-view modification.

A method for measuring the angle between left atrial and left ventricular long axes using 3D echocardiography

“…Using cardiac MRI, the concept of the angle between the LA and LV long axes (LA‐LV angle) measurement has recently been established 6 . To our knowledge only a single study has previously utilized this concept in CT imaging, concerning only volume measurements, and has found only minor differences in 2D volume calculation accuracy with respect to the LA‐LV angle 7 . Using echocardiography, atrial‐focused views have been shown to yield better LA volume estimations than traditional LV‐focused views, 8 but the determinants of this difference—such as, possibly, the LA‐LV angle—have not been known previously.…”

“…6 To our knowledge only a single study has previously utilized this concept in CT imaging, concerning only volume measurements, and has found only minor differences in 2D volume calculation accuracy with respect to the LA-LV angle. 7 Using echocardiography, atrial-focused views have been shown to yield better LA volume estimations than traditional LV-focused views, 8 but the determinants of this difference-such as, possibly, the LA-LV angle-have not been known previously. Even atrial-focused views may still misrepresent true LA size due to difficulty to verify a non-foreshortened view and due to constraints regarding acoustic windows 9 -indeed, getting a 2D view aligned to the LA axis would sometimes require absurd acoustic windows through the intestine.…”