Cuocolo A, Santomauro M, Pace L, Celentano L, Nappi A, Nicolai E, Chiariello M, Salvatore M. Department of Nuclear Medicine, Second Medical School, Universita Federico II, Naples, Italy. Eur J Nucl Med19(2):119-24, 1992. In this study we compared the results of exercise and trans-oesophageal atrial pacing (TAP) technetium-99m methoxyisobutyl isonitrile (99mTc-SESTAMIBI) cardiac imaging in the evaluation of left ventricular (LV) function and myocardial perfusion in patients with angiographically proven coronary artery disease. Ten patients (8 men and 2 women, mean age 59 +/- 6 years) were submitted to 3 separate injections of 99mTc-SESTAMIBI, one under control conditions, one after exercise and one after TAP. LV ejection fraction, as measured by electrocardiogram (ECG) gated first pass, decreased from 49 +/- 5% under control conditions to 42 +/- 6% during exercise (P less than 0.05 versus control) and to 43 +/- 8% during TAP (P less than 0.05 versus control and insignificant change versus exercise). Segmental myocardial perfusion analysis was performed on a total of 150 myocardial segments. On both exercise and TAP 99mTc-SESTAMIBI studies, 103 segmengts (69% of the total) were normal, 32 (21%) had reversible, and 15 (10%) irreversible, perfusion defects. Relative regional tracer uptake was not statistically different between exercise and TAP in normal regions (91.1 +/- 9.1% versus 90.7 +/- 8.5%, respectively), in regions with reversible (61.9 +/- 12% versus 62.4 +/- 10.4%, respectively) and irreversible perfusion defects (55.8 +/- 7.8% versus 58.8 +/- 9.5%, respectively). Our results demonstrated that 99mTc-SESTAMIBI TAP cardiac imaging shows similar results to 99mTc-SESTAMIBI exercise myocardial scintigraphy in the assessment of LV function and myocardial perfusion in patients with coronary artery disease.