Use of electromagnetic flow probes to assess myocardial performance in man.

Aortic blood flow was measured in 14 patients by means of an electromagnetic flow probe placed around the ascending aorta during cardiac surgery. High fidelity left ventricular pressure was monitored directly, 8 different indices of left ventricular function were derived from these measurements, and compared. Peak aortic blood flow correlated with the conventional indices of left ventricular function derived from left ventricular pressure, but better correlations were obtained for the maximum rate of change of power with respect to time. The clinical advantage of the derivation of this index is small and for clinical purposes peak aortic blood flow and the maximum rate of change of flow provide indices of myocardial performance which are directly available from the instrument.