Differential response of the right and left ventricle to beta-adrenergic stimulation: an echo planar MR study in intact animals.
OBJECTIVE
The purpose of this study was to compare the response in contractility of the right (RV) and left (LV) ventricle of the heart to beta-adrenergic stimulation using an echo planar MR technique.


METHODS
In six sheep, RV and LV pressure-volume (P-V) relationships were constructed simultaneously using intraventricular pressures and volumes measured with echo planar MRI at rest and during dobutamine stress. Contractility changes were quantified by assessment of the end-systolic P-V relationship (ESPVR) and the preload recruitable stroke work (PRSW).


RESULTS
Both the ESPVR the the PRSW showed a significant increase in contractility for both ventricles after dobutamine administration. The increase in contractility was significantly larger for the LV than for the RV, both measured wit the ESPVR (p < 0.0003) and the PRSW (p < 0.007).


CONCLUSIONS
This study shows the usefulness of echo planar MRI to assess myocardial contractility of both ventricles simultaneously. Furthermore, the study shows that beta-adrenergic stimulation has a significantly greater positive inotropic effect on LV contractility than on RV contractility.
Jerzewski
A
A
Department of Cardiology, Leiden University Medical Centre, The Netherlands.
Pattynama
P M
PM
Steendijk
P
P
Leeuwenburgh
B P
BP
de Roos
A
A
Baan
J
J
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D004280:Dobutamine / Q000494:pharmacology*; D017352:Echo-Planar Imaging / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D005780:Gelatin / Q000008:administration & dosage; D006352:Heart Ventricles / Q000033:anatomy & histology / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects*; D010952:Plasma Substitutes / Q000008:administration & dosage; D015203:Reproducibility of Results; D012756:Sheep; D013268:Stimulation, Chemical; D013318:Stroke Volume / Q000187:drug effects; D013386:Succinates / Q000008:administration & dosage
D000318:Adrenergic beta-Agonists; D010952:Plasma Substitutes; D013386:Succinates; C060085:succinylated gelatin; D004280:Dobutamine; D005780:Gelatin