Hormonal and plasma volume changes after presyncope
Version of Record online: 24 MAR 2011
© 2011 The Authors. European Journal of Clinical Investigation © 2011 Stichting European Society for Clinical Investigation Journal Foundation
European Journal of Clinical Investigation
Volume 41, Issue 11, pages 1180–1185, November 2011
How to Cite
Hinghofer-Szalkay, H., Lackner, H. K., Rössler, A., Narath, B., Jantscher, A. and Goswami, N. (2011), Hormonal and plasma volume changes after presyncope. European Journal of Clinical Investigation, 41: 1180–1185. doi: 10.1111/j.1365-2362.2011.02523.x
- Issue online: 10 OCT 2011
- Version of Record online: 24 MAR 2011
- Received 9 December 2010; accepted 22 February 2011
- Passive head-up tilt;
Eur J Clin Invest 2011; 41 (11): 1180–1185
Background Aim of this study was to test the hypothesis that after presyncope, some blood hormone pools increase while others decrease.
Materials and methods In twelve healthy male adults, we determined plasma volume changes with plasma mass densitometry and hormone levels. The following were compared: supine rest, presyncope and 20-min post-presyncopal supine rest. We determined plasma renin activity (PRA), aldosterone, adrenocorticotropic hormone (ACTH), adrenomedullin and vasopressin (AVP) from venous blood samples.
Results Using passive 4-min 70° head-up tilt followed by 4-min sequences of additional lower body negative pressure of increasing intensity (15 mmHg steps), presyncope occurred after 11·6 ± 2·8 min, at which time plasma volume was reduced by 15·5 ± 7·4%, aldosterone increased by 37%, ACTH by 75%, PRA by 187% and AVP about 16-fold in average (all P < 0·01); no significant changes in adrenomedullin were seen. Twenty-min post-presyncope, ACTH increased above presyncopal levels (+36%, P < 0·05), aldosterone by 35% (P = 0·07). PRA (−47%, P < 0·01) and AVP (−84%, P < 0·05) decreased below presyncopal but were still above supine control (P < 0·01); similarly, plasma density fell by 2·17 ± 0·97 g L−1 below presyncopal (P < 0·01), but above supine control (P < 0·05), indicating rapid recovery (83% of initial plasma volume).
Conclusions We conclude that during the 20-min supine post-syncopal period, plasma volume, PRA and AVP return closer to baseline but aldosterone and ACTH continue increasing. The magnitude of observed concentration changes cannot be explained by haemoconcentration/haemodilution, rather it appears that the observed changes are indicative of hormone-specific endocrine activation patterns in the recovery phase.