Subclinical Left Atrial Remodeling in Healthy Adults with Left Ventricular ‘Rigid Body Rotation’—Detailed Analysis from the Three-Dimensional Speckle-Tracking Echocardiographic MAGYAR-Healthy Study

<b>Background.</b> While the basal region of the left ventricle (LV) rotates in a clockwise (cw) direction, the apical regions of the LV rotate in a counterclockwise (ccw) direction in healthy circumstances. Although LV rotational mechanics help optimize LV ejection, in some cases, LV twist is missing. This clinical situation, when the LV base and the apex rotate in the same cw or ccw direction, is called LV 'rigid body rotation' (LV-RBR). Three-dimensional speckle-tracking echocardiography (3DSTE) seems to be optimal for the simultaneous assessment of the LV and the left atrium (LA). Therefore, the present study aimed to determine the features of LA remodeling in healthy adults having 3DSTE-derived LV-RBR as compared to subjects with normally directed LV rotational mechanics. <b>Methods.</b> This study consisted of 165 healthy subjects (mean age: 33.1 ± 12.3 years, 75 males), from which 156 individuals showed normally directed LV rotational mechanics, while 9 cases had LV-RBR. <b>Results.</b> When LV-RBR subjects were compared to subjects with normally directed LV rotational mechanics, all LA volumes were increased with preserved LA stroke volumes and (non-significantly) reduced LA emptying fractions. When subgroups were compared with each other, it has been clarified that an enlargement of the LA with increased volumes was limited only to ccwLV-RBR cases. While reduced global peak LA longitudinal strain could be detected in LV-RBR subjects as compared to subjects with normally directed LV rotational mechanics, which was limited to cases with the ccw form of LV-RBR (15.1 ± 4.7% vs. 26.6 ± 9.0%, <i>p</i> < 0.05), the global peak LA radial strain was increased in subjects with cwLV-RBR (-23.4 ± 6.3% vs. -14.7 ± 8.0%, <i>p</i> < 0.05). Increased global LA radial strain at atrial contraction could be detected in LV-RBR subjects (-9.9 ± 7.1% vs. -5.2 ± 5.2%, <i>p</i> < 0.05), which was present in both ccw and cw LV-RBR cases. <b>Conclusions.</b> In healthy adults presenting LV-RBR, subclinical LA remodeling could be detected in both forms of LV-RBR, but more pronounced in those who present a counterclockwise-oriented form.