Effect of acute body positional changes on the haemodynamics of rats with and without myocardial infarction

Abstract

In humans, the lateral recumbent position has a beneficial effect on haemodynamics. If this effect is substantial in small animals too, there is a risk of misinterpretation in preclinical investigations. Therefore, the aim of this study was to analyse the impact of acute changes in body position on haemodynamics in rats. Healthy rats (n = 21) and rats post myocardial infarction (n = 20) were randomly positioned supine, prone, or on the right or left side. In each position, we measured haemodynamic parameters by pressure-tip catheter and thermodilution. We found that left ventricular contractility (dP/dt max ) was significantly elevated in both lateral positions as compared to the supine position in healthy rats. In healthy rats and following infarction, cardiac index (CI) and stroke volume index (SVI) were significantly higher in both lateral positions as compared to the supine or prone position. Of importance, if SVI values in the supine position in healthy rats (0.095 ± 0.003 ml (100 g) −1 ) are compared to SVI values measured in different positions after myocardial infarction, the SVI can be either significantly lower in the supine (0.084 ± 0.003 ml (100 g) −1 ) or significantly higher in the left lateral position (0.105 ± 0.003 ml (100 g) −1 ). We conclude that post myocardial infarction and in healthy control rats, important haemodynamic values are increased in lateral positions as compared to prone or supine positions. Analysing haemodynamic data in rats may therefore result in misinterpretation if the body position is inconsistent.

Long‐Term Evaluation of Myoblast Seeded Patches Implanted on Infarcted Rat Hearts

“…The analysis was also performed in a blinded manner. The tip of a 1.4 F pressure catheter (Millar Mikro‐Tip, Millar Instruments, Houston, TX, USA) was placed through the apex of the heart into the LV before the animals were placed in a left lateral position (6). After a stabilization period of 5 min, the pressure curves of 10–15 subsequent arbitrarily chosen beats were recorded and used to calculate the LV contractility (dP/dt max ), LV relaxation (dP/dt min ), LV end‐diastolic pressure (LVEDP), and heart rate.…”

Myoblast-seeded biodegradable scaffolds to prevent post–myocardial infarction evolution toward heart failure

“…The tip of a 1.4F pressure catheter (Millar Mikro-Tip; Millar Instruments, Inc, Houston, Tex) was placed via the right carotid artery into the left ventricle before the animals were positioned in the left lateral position. 14 After a stabilization period of 5 minutes, the pressure curves of 10 to 15 subsequent arbitrarily chosen beats were recorded and used to calculate the left ventricular contractility (dP/ dt max ), relaxation (dP/dt min ), end-systolic pressure (LVESP), enddiastolic pressure (LVEDP), and heart rate.…”

Respuesta adaptativa del niño con síndrome de bajo gasto cardiaco a los cambios de posición en la unidad de cuidado intensivo pediátrico

“…El estudio concluye que el volumen sistólico ventricular se reduce significativamente en el corazón enfermo con cada cambio de posición, mientras que el corazón sano mantiene un volumen sistólico normal en todas las posiciones (23). La severidad de la insuficiencia miocárdica que se genera en el síndrome de bajo gasto cardiaco, sin lugar a dudas, explica la intolerancia a la intervención de enfermería: cambio de posición particularmente en los grupos II y III.…”