Systolic Time Intervals During Lower Body Negative Pressure

摘要

Systolic time intervals (STI) were utilized to assess changes in left ventricular function (LVF) among 8 male USAF volunteers exposed to lower body negative pressure (LBNP). Significant prolongation of the preejection period (PEP) shortening of the left ventricular ejection time (LVET), and consequently an increasing PEP/LVET were observed at both 40 and 50 MM Hg negative pressure. A correlation between cardiac index and observed STI changes is noted. Changes in preload, contractility and after load may account for the observed findings. STIs appear to be a reliable noninvasive mode for examination of transient and continuous changes in LVF during LBNP. (Author)