Reduction of left ventricular preload by lower body negative pressure alters Doppler transmitral filling patterns

The objective of this study was to evaluate the effect of alterations in preload induced by lower body negative pressure on Doppler transmitral filling patterns. Echocardiograms and Doppler recordings were performed in 18 normal young men (aged 23 to 32 years) during various levels of lower body negative pressure (0, −20 and −50mm Hg). Lower body negative pressure induced a reduction in diastolic velocity integral (from 12.17 ± 0.79 to 8.42 ± 0.71 cm, p = 0.0067) and consequently left ventricular diastolic diameter (from 5.11 ± 0.09 to 4.45 ± 0.1 cm, p < 0.0001). There was a significant reflex increase in heart rate from 59.9 ± 1.9 to 77.1 ± 2.4 beats/min (p < 0.0001), but blood pressure was unchanged.