Echocardiographic evaluation of hemodynamic changes during upright tilt test. Correlation with test's results

The aim of our study was to evaluate the variations of the hemodynamic parameters of the left ventricle during upright tilt test (UTT) by mean of echocardiography. We studied 12 patients referred for syncope or presyncope. The parameters considered were: left ventricle end diastolic volume (LVEDV); left ventricle end systolic volume (LVESV); left ventricle ejection fraction (LVEF). The measurements were performed at baseline and every 10 minutes during UTT. A relevant decrease of LVEDV and LVESV was evidenced only in the 5 patients with positive UTT, whereas no correlations emerged between the hemodynamic variations and heart rate and blood pressure changes during the test. These results seem to confirm the significance of a progressive reduction of venous return in the mechanism of tilt-induced syncope, as a common way to different autonomic efferent responses.