Radionuclide ventriculography and central aorta pressure change in noninvasive assessment of myocardial performance

Systolic pressure-volume diagrams were obtained noninvasively by measuring the systolic central aortic pressure with a new device and by combining the pressure measurements, thus obtained, with absolute volume measurements obtained by radionuclide ventriculography during ejection. By dividing the peak power by the time elapsed from the beginning of ejection to the peak power point, the ejection rate of change of power (ERCP) was calculated. The ability of this index to assess left ventricular function at rest and exercise was evaluated in ten healthy subjects. ERCP proved to be more sensitive than global left ventricular ejection fraction increasing fivefold from rest to exercise compared with only 20% increase in global ejection fraction. ERCP increased dramatically postexercise from 3411 ± 2173 to 18162 ± 14633 gm/sec², median 12750, 95% confidence interval 9700-29600, in healthy, while in patients it increased twofold from 2637 ± 824 to 5062 ± 1897 gm/sec², median 4070, 95% confidence interval 2800-7030, p