Alterations in left ventricular volumes and ejection fraction during atrial pacing in patients with coronary artery disease: assessment with radionuclide ventriculography.

The present study was performed to determine the utility of radionuclide ventriculography (RNV) in conjunction with atrial pacing in the identification of individuals with coronary artery disease. Accordingly, left ventricular end-diastolic volume index, end-systolic volume index, ejection fraction, and regional wall motion were measured with radionuclide ventriculography before and during atrial pacing in 37 patients: 27 with and 10 without (control subjects) coronary artery disease. In the control subjects, pacing caused a decrease in end-diastolic volume index (77 +/- 19 [mean +/- SD] ml/M2 at rest, 50 +/- 18 ml/M2 at peak pacing; p less than 0.001), a decrease in end-systolic volume index (34 +/- 14 ml/M2 at rest, 19 +/- 9 ml/M2 at peak pacing; p less than 0.001), an increase in ejection fraction (0.61 +/- 0.11 at rest, 0.66 +/- 0.11 at peak pacing; p = 0.006); and no deterioration in wall motion. In 16 patients with coronary artery disease who developed ECG and/or metabolic evidence of ischemia during pacing, end-diastolic volume index decreased (87 +/- 26 ml/M2 at rest, 69 +/- 24 ml/M2 at peak pacing; p less than 0.001), end-systolic volume index was unchanged (43 +/- 20 ml/M2 at rest, 44 +/- 21 ml/M2 at peak pacing; p = NS), ejection fraction decreased (0.55 +/- 0.12 at rest, 0.40 +/- 0.14 at peak pacing; p less than 0.001), and new wall motion abnormalities developed in 14. In 11 patients with coronary artery disease but no ECG or metabolic evidence of ischemia, pacing caused a decrease in end-diastolic volume index (80 +/- 26 ml/M2 to 61 +/- 31 ml/M2; p less than 0.001), a decrease in end-systolic volume index (36 +/- 17 ml/M2 to 28 +/- 20 ml/M2; p = 0.002), no change in ejection fraction (0.60 +/- 0.11 to 0.60 +/- 0.13; p = NS), and new wall motion abnormalities in four. Although the specificity of these scintigraphic measurements for the identification of patients with coronary artery disease was excellent (1.0), the combined sensitivity of all scintigraphic measurements was high only if ECG or metabolic evidence of ischemia was present: 0.94 in patients with evidence of ischemia but only 0.36 in those without ischemia. Thus radionuclide ventriculography during incremental atrial pacing is useful in the identification of patients with coronary artery disease only if ischemia is induced.