Reduced preload elicits increased LV twist in healthy humans: An echocardiographic speckle-tracking study during lower body negative pressure

• Published in: Clinical physiology and functional imaging 2011-09, Vol.31 (5), p.382-389
• Main Authors: HODT, Anders, HISDAL, Jonny, STUGAARD, Marie, STRANDEN, Einar, ATAR, Dan, STEINE, Kjetil
• Format: Article
• Language: English
• Subjects: Adult; Analysis of Variance; Biological and medical sciences; Biomechanical Phenomena; Blood Pressure; Fundamental and applied biological sciences. Psychology; Heart Ventricles - diagnostic imaging; Humans; Imaging; Lower Body Negative Pressure; Male; Mathematical analysis; Myocardial Contraction; NTA; Reduction; Regional; Rest; Rotation; Stroke Volume; Ultrasonography; Ventricular Function, Left; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Young Adult
• ISSN: 1475-0961; 1475-097X
• DOI: 10.1111/j.1475-097X.2011.01029.x

In normal left ventricles (LV), counterclockwise rotation (CCR) and net twist angle (NTA) have shown important roles during ejection. We investigated the effect of reduced preload by lower body negative pressure (LBNP) on CCR and NTA. Twelve healthy men were examined at rest, LBNP -20 and -40 mmHg. By two-dimensional speckle-tracking imaging, we measured rotation at four short-axis levels: basal, papillary, sub-papillary and apical. LV NTA was calculated as apex-to-base difference in rotation. Additionally, regional end-diastolic (EDA) and end-systolic area (ESA) were measured and regional area fraction (RAF) calculated [(EDA-ESA)/EDA] × 100). From rest to LBNP -40 mmHg, rotation at basal and papillary levels was unchanged. At sub-papillary level, rotation increased from 3·2 ± 3·6 to 5·8 ± 4·7° (P