Assessment of cardiac function in mice using ventricular catheterization and MRI derived Pressure‐Volume loops

Abstract

Stroke work normalized to end diastolic volume derived from pressure‐ volume (PV) relationships is regarded as a gold standard for measurement of the contractile status. Though conductance catheters are widely used to obtain PV relationships in the heart, it does not provide accurate measurements of absolute ventricular volumes. Magnetic resonance imaging (MRI) on the other hand provides accurate measurement of Left ventricular (LV) cavity volume but does not provide absolute measurement of LV pressure. The aim of this study was to demonstrate the feasibility of obtaining MRI volume data while invasively measuring LV pressure in wild type C57BL/6 and δ sarcoglycan null (Scgd−/−). LV pressure was measured invasively using a MR compatible fluid filled pressure transducer and volume data collected simultaneously from a 7 Tesla scanner at rest and during infusion of Dobutamine. Stroke work was calculated from the integrated area within the PV loop. Stroke work of Scgd−/− decreased from 2.8±0.56 mmHg mL at rest to 1.1±0.49 mmHg mL at stress but did not change significantly in WT. Decreased stroke work in Scgd−/− mice under stress was associated with LV pressure decline which may be related to vascular abnormalities in these mice as previously reported. This study demonstrates for the first time that invasive pressure and MRI derived volume measurements can be made simultaneously in mice.