Measuring left ventricular function in the normal, infarcted and CORM-3-preconditioned mouse heart using complex admittance-derived pressure volume loops.

INTRODUCTION: Miniaturized conductance catheters have been successfully applied to measure left ventricular (LV) function in the mouse to assess cardiac or pharmacological interventions. Complex admittance, in contrast to existing methods using conductance catheters, produces an estimate of the parallel admittance of cardiac muscle that can be used to correct the measurement in real-time. The aim of this study was to validate the use of complex admittance to assess LV function in normal and infarcted hearts.
METHODS: Using a single conductance catheter, we directly compared measures of LV function using a specially developed admittance system (ADVantage system) and a traditional conductance-derived pressure-volume (PV) system. We subjected mice to focal myocardial ischaemia-reperfusion injury while measuring cardiac function to determine the ability of the new system to distinguish between normal, and dysfunctional LV, contractile performance.
RESULTS: LV pressure-volume loops from complex admittance is a reproducible and reliable method of determining LV function, producing data similar to that of the conductance catheter. Our data suggest that the ADVantage system records larger systolic LV cavity volumes when compared to the traditional conductance system in the same animal. In addition, we demonstrate marked LV dysfunction following coronary artery occlusion and reperfusion which is ameliorated using CORM-3, a cardioprotective agent that liberates carbon monoxide (CO).
CONCLUSION: The ADVantage system is both effective and reproducible in measuring LV function and dysfunction in the mouse, without the need for complicated interventions to calibrate the measurements. This may mark the way toward an accurate assessment of murine cardiac function.