MAGNETIC-RESONANCE-IMAGING ANALYSIS OF LEFT-VENTRICULAR PRESSURE-VOLUME RELATIONS - VALIDATION WITH THE CONDUCTANCE METHOD AT REST AND DURING DOBUTAMINE STRESS

The accuracy of magnetic resonance (MR) imaging was assessed for in vi vo measurement of the ventricular end-systolic pressure-volume relatio n (ESPVR) and preload recruitable stroke work (PRSW). The conductance catheter was used as reference. In 10 pigs, ventricular volumes were m easured with both methods under different loading conditions at two le vels of contractility. Increased contractility resulted in a significa nt leftward shift of the ESPVR and PRSW for both methods. The magnitud e of these shifts was on average similar for the two methods; MR imagi ng, 6.9 ml for ESPVR, 9.3 ml for PRSW; and the conductance catheter, 7 .4 ml for ESPVR, 9.1 ml for PRSW. It was concluded that MR imaging may be used for in vivo analysis of pressure-volume relations, and that i ts sensitivity for detecting contractility changes is similar to that of the conductance catheter method.