REST AND TREADMILL EXERCISE FIRST-PASS RADIONUCLIDE VENTRICULOGRAPHY - VALIDATION OF LEFT-VENTRICULAR EJECTION FRACTION MEASUREMENTS

Background. To assess the accuracy of rest and treadmill exercise firs t-pass radionuclide ventriculographic measurements of left ventricular ejection fraction (LVEF), 40 patients underwent treadmill exercise fi rst-pass and bicycle exercise equilibrium radionuclide ventriculograph y. To determine the frequency of technically adequate treadmill exerci se first-pass studies, an additional 128 consecutive patients undergoi ng treadmill exercise first-pass procedures during stress Tc-99m-label ed sestamibi myocardial perfusion studies were assessed.Methods and Re sults. The treadmill exercise first-pass procedure used a multicrystal camera and an Am-241 point source to allow for correction of patient motion. Excellent correlations were observed between resting first-pas s and resting equilibrium LVEF (r = 0.98; standard error of the estima te = 5.6). A high correlation was also observed between treadmill exer cise first-pass and bicycle equilibrium exercise LVEF measurements (r = 0.85, standard error of the estimate = 7.6). Treadmill first-pass LV EF systematically underestimated the bicycle equilibrium LVEF. Intraob server agreement for rest and exercise first-pass LVEF was high (r val ues of 0.98 and 0.91, respectively). Of the 168 consecutive treadmill exercise first-pass studies evaluated for technical adequacy, 21 (12.5 %) were deemed technically inadequate, with most of the sources of err or being avoidable. The frequency of technically adequate studies was as high (87%) in high levels of exercise (Bruce stages 3 and 4) as in lower levels (88%). The findings of this study validate the first-pass treadmill exercise LVEF measurement. Conclusion. This procedure now p rovides the option for combining the information of peak treadmill exe rcise LVEF with measurements of exercise myocardial perfusion from the same injection of radioactivity.