A comparison between left ventricular ejection time measurement methods during physiological changes induced by simulated microgravity

New Findings What is the central question of this study? First, we validated easy‐to‐use oscillometric left ventricular ejection time (LVET) against echocardiographic LVET. Second, we investigated progression of left ventricular ejection time index (LVETI), pre‐ejection period index (PEPI), total electromechanical systole index (QS2I) and PEP/LVET ratio during 60 days of head‐down tilt (HDT). What is the main finding and its importance? The LVETosci and LVETecho showed good agreement in effect direction. Hence, LVETosci might be useful to evaluate cardiovascular responses during space flight. Moreover, the approach might be useful for individual follow‐up of patients with altered ejection times. Furthermore, significant effects of 60 days of HDT were captured by measurements of LVETI, PEPI, QS2I and PEP/LVET ratio. Systolic time intervals that are easy to detect might be used as parameters reflecting cardiovascular deconditioning. We compared left ventricular ejection time (LVET) measured via ultrasound Doppler on the left ventricular outflow tract with oscillometrically measured LVET, measured at the brachialis. Furthermore, we assessed the progression of the left ventricular ejection time index (LVETI), the pre‐ejection period index (PEPI), the Weissler index (PEP/LVET) and the total electromechanical systole index (QS2I) during prolonged strict head‐down tilt (HDT) bed rest, including 16 male and eight female subjects. Simultaneous oscillometric and echocardiographic LVET measurements showed significant correlation (r = 0.53 with P = 0.0084 before bed rest and r = 0.73 with P