Dynamic left atrial strain by dobutamine: Evidence for relationship with both left ventricular strain and atrioventricular volumetrics

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Left atrial strain (LASR) by speckle-tracking echocardiography allows the assessment of LA function in each phase of the cardiac cycle. However, its determinants and its relation with left ventricular (LV) function have not yet been fully described. Moreover, a potential effect of the LV cavities volumes has been recently proposed. Purpose Purpose of the study was to assess the effect of LV functional indices to LASR in combination with LA and LV volumes both at rest (R) and during dobutamine stress echo (D). Methods We studied 58 consecutive patients (age 59/12, male/female 37/19) who underwent D without evidence of ischemia. Using 2-D speckle tracking in apical views, both LA and LV strain analysis was performed at R and D. The following parameters were estimated: LA volumes (max/min), LA emptying function (max-min/max), LA strain (SR: overall, reservoir, conduit, active), LV volumes (systole: LVSvol, diastole: LVDvol) stroke volume (SV), LV ejection fraction (LVEF), LV longitudinal strain (LVSR) and LA/LV max volume ratio (LA/LVvol). Results At R, among LA indices, LAtotalSR only was related to LVSR (r=0.31, p = 0.02). However, at D, LAcondSR, LAactive SR, LAtotalSR were related to LVSR (r=-0.25/0.36/0.3 respectively, all p<0.001). At R, LAEF, LAactiveSR and LAtotalSR were related with La/LVvol (r=-0.40/-0.40/0.45 respectively, all p<0.002). At D, LAEF, LAreservoirSR, LAactiveSR and LAtotalSR were related with La/LVvol (r=-0.39/-0.31/-0.31/-0.42 respectively, all p<0.001). For the determination of LAactiveSR at R, using stepwise multiple regression analysis including LVEF LVSR LVsv, LVDvol, La/LVvol, the greater contribution was provided by La/LVvol (initial R=0.41), with small improvement by LVSR (final R=0.50, p<0.001). In contrast, at D, the greater contribution for LAactiveSR was provided by LVSR (initial R=0.36) with some improvement by La/LVvol (final R=0.47 p<0.001). For the determination of LAtotalSR at R, the greatest contribution was provided by LA/LVvol (initial R=0.45) with improvement by LVSR (R=0.57) and finally by LVDvol (final R=0.64, p<0.001). For LAtotalSR at D, the greatest contribution was provided also by LA/LVvol (initial R=0.43) with further improvement by LVSR (final R=0.54, p<0.001). Conclusions LA strain indices are determined partially by LV strain both at rest and mainly during inotropic stimulation. However, they are further and beyond LV strain modulated by the ratio of LV and LA volumes, which play a key role for the overall LA strain both at R and during D. The LA active component is less dependent on volumes, and it is coherent to LV strain during inotropic modulation. Nonetheless, dynamic LA strain is of interest since it integrates LV/LA function, thus providing new insights for clinical application.