Radionuclide analysis of peak filling rate, filling fraction, and time to peak filling rate. Response to supine bicycle exercise in normal subjects and patients with coronary disease.

Using gated equilibrium radionuclide angiography, variables of diastolic filling were analyzed at rest and during supine bicycle exercise in normal subjects (Group 1, n = 18), coronary patients with normal resting ejection fractions (Group 2, n = 26), and coronary patients with reduced resting ejection fractions (Group 3, n = 8). Indexes analyzed were peak filling rate and filling fraction during the first third of diastole. At rest, the peak filling rate was significantly lower in coronary patients than in normal subjects (3.18 +/- 0.82 end-diastolic volume [EDV]/s in Group 1 versus 2.41 +/- 0.66 EDV/s in Group 2, p less than 0.005; and 1.34 +/- 0.26 EDV/s in Group 3, p less than 0.001 versus Group 1). These differences persisted at peak exercise. Coronary patients also had significantly lower filling fractions at rest and during exercise than did normal control subjects. The time from end-systole to peak filling rate was longer at rest in patients in Group 2 (203 +/- 52 ms) than in subjects in Group 1 (172 +/- 50 ms, p less than 0.025). This remained true when the time to peak filling was normalized by the R-R interval. Although the exercise time to peak filling was longer in coronary patients in both Groups 2 and 3 than in Group 1, these differences were not apparent when the interval was normalized by the R-R interval. Thus, abnormalities in peak filling rate and filling fraction exist in patients with coronary disease both at rest and during exercise, but large overlaps exist between normal and coronary patients. Caution is advised in comparing the timing of events during diastole because apparent group differences may be related in part to rest or exercise heart rate.