Submitted on December 3, 2004
Accepted on January 3, 2006
Longitudinal but not Circumferential Deformation Reflects Global Contractile Function in the Right Ventricle with Open Pericardium
H. Alex Leather1, Ruggero Ama'1, Carlo Missant1, Steffen Rex2, Frank E Rademakers3, and Patrick F Wouters1*
1 Department of Anesthesiology, Katholieke Universiteit Leuven, Leuven, Belgium
2 Department of Anesthesiology, Katholieke Universiteit Leuven, Leuven, Belgium; Department of Anesthesiology, University Hospital of the RWTH Aachen, Aachen, Germany
3 Department of Cardiology, Katholieke Universiteit Leuven, Leuven, Belgium
* To whom correspondence should be addressed. E-mail: patrick.wouters{at}uz.kuleuven.ac.be.
The clinical evaluation of right ventricular (RV) contractility is problematic because instantaneous RV volumetry is difficult to achieve. Our aim was to test whether global RV contractility can be assessed using regional indices in the longitudinal and/or circumferential axis. Six anesthetized adult ewes were instrumented with a right ventricular conductance catheter and four RV free wall sonomicrometry crystals (interrogating the longitudinal and circumferential axes). Global and regional preload recruitable stroke work (PRSW) was measured using acute vena cava occlusions at baseline, during esmolol and dobutamine infusion, and during stable low preload and high afterload conditions. The agreement between regional and global PRSW was assessed with regression and Bland-Altman analysis. Both regional PRSW indices correlated well with global PRSW in baseline conditions, during inotropic modulation (R2 =0.83 and 0.74 for longitudinal and circumferential regional PRSW respectively) and during preload reduction (R2 = 0.62 and 0.83 respectively), but only longitudinal regional PRSW correlated with global PRSW in increased afterload conditions (R2 =0.59 and 0.13 for longitudinal and circumferential regional PRSW respectively). We conclude that in the open chest-open pericardium animal model, deformation in the longitudinal axis accurately reflects global RV contractile function in baseline conditions and during acute load modulation, whereas circumferential motion is influenced by changes in afterload.
