Easy to detect systolic time intervals may 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 oscillometric measured LVET measured at the brachialis. Furthermore, we assessed the progression of left ventricular ejection time index (LVETI), pre-ejection period index (PEPI) the Weissler index (PEP/LVET) and the total electromechanical systole index (QS2I) during prolonged strict head-down tilt bedrest including 16 male and 8 female subjects. Simultaneous oscillometric and echocardiographic LVET measurements show significant correlation (r = 0.53 with p = .0084 before bedrest and r = 0.73 with p < .05 at the last day of bedrest). The shortening of LVET during head-down tilt bedrest measured with both approaches is highly concordant in their effect direction with a concordance rate of 0.96. Our results furthermore report a significant decrease of LVETI (p < .0001) and QS2I (p = .0992) as well as a prolongation of PEPI (p = .0049) and PEP/LVET (p = .0003) during head down tilt bedrest over 60 days. 4 days after bedrest LVETI fully recovers to its baseline value. Because of the relationship between shortening of LVETI and heart failure progression, the easy-to-use oscillometric method might be not only a useful measure to evaluate the cardiovascular system during space flights, butcould also be of high value in a clinical setting.

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