Received January 25, 2005
Revised March 17, 2005
Accepted after revision April 15, 2005
Effect of acute body positional changes on the hemodynamics of rats with and without myocardial infarction
Matthias Siepe 1*,
Daniel M Ruegg 1,
Marie-Noelle Giraud 1,
Johanne Python 1,
Thierry Carrel 1,
Hendrik T Tevaearai 1
1 University Hospital Bern,
* To whom correspondence should be addressed. E-mail: matthias.siepe{at}web.de.
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Abstract |
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In humans, the lateral recumbent position has a beneficial effect on hemodynamics. If this effect is substantial in small animals too, there is a risk of misinterpretation in preclinical investigations. Therefore, we aim to analyze the impact of acute changes in body position on hemodynamics in rats.
Healthy rats (n=21) and rats post-myocardial infarction (n=20) were randomly positioned supine, prone, right, and left side. In each position, we measured hemodynamics by pressure-tip-catheter and thermodilution.
We found that LV-contractility (dP/dtmax) was significantly elevated in both lateral positions as compared to supine position in healthy rats. In healthy and post-infarction rats, cardiac index (CI) and stroke volume index (SVI) were significantly higher in both lateral positions as compared to supine or prone position. Importantly, if SVI values of the supine position in healthy rats (0.095±0.003 ml/100g) are compared to the positional parameters after myocardial infarction, the SVI can be either significantly lower in supine (0.084±0.003ml/100g) or significantly higher on left lateral position (0.105±0.003ml/100g).
To conclude, in post-myocardial infarction and in healthy control rats, important hemodynamic values are increased in lateral positions as compared to prone or supine position. Analyzing hemodynamic data in rats may therefore result in misinterpretation if the body position is inconsistent.
Key Words:
Cardiovascular, Posture, Vascular blood flow
