Quantitative analysis of T-wave amplitude during parabolic flight

Our goal was to develop a method for the analysis of T-wave maximum amplitude (Tmax), to quantify its changes with gravity (G^z) during parabolic flight, and test the hypothesis that microgravity (0 G^z) induces alteration in ventricular repolarization. ECG was obtained in 12 normal male subjects in upright position during consecutive parabolas with lower-body negative pressure (LBNP) randomly activated at 0 G^z. The X, Y and Z leads were used to compute vector V. Each QQ was classified according to G^z (1 G^z, 1.8 GZ, 0 G^z, 1 G^z recovery) at its time occurrence and used to obtain a template, from which Tmax was computed. At 0 G^z, Tmax showed a significant increase (15%+4%), compared to 1 G^z. With LBNP, the Tmax increase at 0 G^z was only 8%+4%. At 1 G^z recovery, Tmax was increased by 5%+2%. Microgravity influences ventricular repolarization by increasing T wave amplitude.