title: Reduction of left ventricular preload by lower body negative pressure alters Doppler transmitral filling patterns.
abstract: 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 -50 mm 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 less than 0.0001). There was a significant reflex increase in heart rate from 59.9 +/- 1.9 to 77.1 +/- 2.4 beats/min (p less than 0.0001), but blood pressure was unchanged. This reduction in preload altered Doppler transmittral filling patterns as follows: 1) peak early velocity (E) decreased from 59.2 +/- 3.8 to 39.1 +/- 1.7 cm/s (p less than 0.0001); 2) atrial filing velocity (A) was unchanged (35.58 +/- 1.5 to 33.52 +/- 1.4 cm/s, p = 0.517); 3) E/A ratio decreased from 1.7 +/- 0.13 to 1.19 +/- 0.08 (p = 0.0087); 4) mean acceleration (from 482 +/- 37 to 390 +/- 27 cm/s2, p = 0.03) and mean deceleration (from 327 +/- 31 to 169 +/- 21 cm/s2, p less than 0.001) of the early filling wave were significantly reduced; and 5) peak acceleration (from 907 +/- 42 to 829 +/- 29 cm/s2) and peak deceleration (from 771 +/- 94 to 547 +/- 76 cm/s2) also decreased, but not significantly.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Division of Cardiovascular Medicine, University of Kentucky Medical Center, Lexington 40536-0084.
authors.forename: M R
authors.initials: MR
authors.lastname: Berk
authors.forename: G Y
authors.initials: GY
authors.lastname: Xie
authors.forename: O L
authors.initials: OL
authors.lastname: Kwan
authors.forename: C
authors.initials: C
authors.lastname: Knapp
authors.forename: J
authors.initials: J
authors.lastname: Evans
authors.forename: T
authors.initials: T
authors.lastname: Kotchen
authors.forename: J M
authors.initials: JM
authors.lastname: Kotchen
authors.forename: A N
authors.initials: AN
authors.lastname: DeMaria
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology*; D003971:Diastole / Q000502:physiology; D015150:Echocardiography, Doppler; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008150:Lower Body Negative Pressure; D008297:Male; D012016:Reference Values; D016277:Ventricular Function, Left / Q000502:physiology*