Abstract
Diastolic and systolic parameters of left ventricular performance were characterized from high-frequency time-activity curves obtained in 10 normal volunteers (mean age 29 ± 4 yr), in 25 patients with normal coronary arteries, and in 50 patients with coronary artery disease (CAD) at rest and during three stages of exercise radionuclide angiography. In the normal volunteers ejection fraction was 65 ± 5% (SD) at rest and 78 ± 5% with exercise (p < .001). In patients with normal coronary arteries ejection fraction was 64 ± 5% at rest and 72 ± 8% with exercise (p < .0001). In patients with CAD resting ejection fraction was 60 ± 10% and that during exercise was 61 ± 13% (p = NS). Peak diastolic filling rate in the first half of diastole, peak systolic ejection rate, and times to peak rates and to end-systole were measured. In the normal subjects resting peak distolic filling rate was 3.1 ± 0.6 end-diastolic counts/sec and it increased in all subjects with exercise to 3.6 ± 0.7 (p < .05). In patients with normal arteries and those with CAD peak diastolic filling rate was 2.3 ± 0.8 at rest and with exercise this parameter increased to 3.2 ± 1.1 (p < .001) in patients with normal arteries and fell to 1.7 ± 0.6 in those with CAD (p < .001). Peak systolic ejection rate decreased from 2.5 ± 0.8 to 1.9 ± 0.8 with exercise in patients with CAD (p < .001). The sensitivity of wall motion and ejection fration response to exercise for detection of CAD in patients was 62% (80% excluding those with one-vessel disease), with no false-positive results. Sensitivity and specificity of peak systolic ejection rate were 66% and 67%, respectively. Peak diastolic filling rate exercise/rest ratio was greater than 1 for patients with normal and 1 or less for patients with diseased arteries, with sensitivity of 98% and specificity of 94%. Thus, alteration of peak diastolic filling rate during exercise is a very sensitive and specific indicator of ischemic heart disease.