P863Left ventricular apex level is the major determinant of twist mechanics magnitude

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Purpose. Left ventricular (LV) torsional deformation is measured by 2D speckle tracking acquiring LV basal short-axis at mitral valve level and apical short-axis at a LV level where papillary muscles are no more visible. Intuitively, the more distal apical short axis is acquired the more twist value results high. We tested if the level at witch LV apex is recorded influences twist measurements.Methods: 34 healthy subjects underwent complete 2D echo Doppler: basal and apical short-axis views were acquired to measure twist and untwisting rate. 3D echocardiography (3D echo) full volume apical view was recorded. In each subject, by 3D echo True Apex was defined as the last apical slice at which LV cavity was visible, whereas False Apex was defined as the LV apical short axis plane with antero-posterior and transversal diameters equal to those of LV short-axis used for torsional analysis. The ratio between the distance of False and True Apex from LV base was calculated and expressed as percentage (False/True Apex). Diastolic function was evaluated by measuring E/e'.Results: False/True Apex was strongly related to the magnitude of twist (Figure) and untwisting rate (r=0,73, p<0,001; r=-0,509, p=0,007, respectively). By linear regression analysis determinants of twist were: False/True Apex (B=,227; p<,001), and E/e' (B=-,580; p=,011); whereas of untwist rate was: False/True Apex (B=-1,075; p<,001).Conclusions: The current suggested method to record apical short-axis view for twist analysis needs standardization. 3D echo may be the key tool for the localization of the apical level at which apical rotation must be measured.

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