Correlations between vegetative autonomic function and specific left atrial functions in healthy adults: Insights from the three-dimensional speckle-tracking echocardiographic MAGYAR-Healthy Study.

Introduction: The functioning of the left atrium (LA) is partly controlled by the neural system. It was purposed to evaluate correlations between the result of Ewing's 5 standard cardiovascular reflex tests (SCRTs) characterizing autonomic function and LA volumetric and functional features as assessed by three-dimensional speckle-tracking echocardiography (3DSTE) in healthy individuals.
Materials and Methods: The current study comprised 18 healthy volunteers being in sinus rhythm (mean age: 35 ± 12 years, 10 men). Measurement of blood pressure, ECG, 5 SCRTs, two-dimensional Doppler echocardiography and 3DSTE were performed. These parameters were in normal ranges in all cases.
Results: From LA volumetric parameters, only systolic total atrial emptying fraction (r = 0.559, p = 0.037) and early diastolic passive atrial emptying fraction (r = 0.539, p = 0.047) correlated with systolic blood pressure response to standing representing sympathetic autonomic function. From LA strains, peak mean segmental LA radial strain (RS) (r = -0.532, p = 0.050), global and mean segmental LA circumferential strain (CS) (r = 0.662, p = 0.010 and r = 0.635, p = 0.015, respectively) representing systolic LA function correlated with Valsalva ratio representing parasympathetic autonomic function. Global LA-RS (r = -0.713, p = 0.040) and LA-CS (r = 0.657, p = 0.011) and mean segmental LA-CS (r = 0.723, p = 0.003) at atrial contraction representing end-diastolic atrial contraction showed correlations with Valsalva ratio, as well. Peak global and mean segmental LA-CS (r = 0.532, p = 0.050 and r = 0.530, p = 0.050) and the same strains at atrial contraction (r = 0.704, p = 0.005 and r = 0.690, p = 0.006) representing systolic function and end-diastolic atrial contraction correlated with systolic blood pressure response to standing representing both parasympathetic and sympathetic autonomic functions.
Conclusions: Significant correlations between features of vegetative autonomic function represented by Ewing's 5 SCRTs and specific LA functions represented by 3DSTE-derived LA volume-based functional properties and strains could be demonstrated in healthy adults.
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