Serial assessment of left ventricular performance at rest and during bicycle exercise by ECG-gated myocardial perfusion SPECT

The present study evaluates left ventricular performance during exercise by ECG-gated myocardial perfusion SPECT with short-time data collection. Methods: The study population consisted of 10 healthy volunteers (Group N) and 9 patients with ischemic heart disease (Group 1). Seven patients in Group I had a history of prior myocardial infarction. Rest ECG-gated SPECT was performed 40 min after an injection of Tc-99m-tetrofosmin (555-740 MBq). After resting data acquisition, Group N underwent up to two 5-min stages of exercise (75 and 125 watts) on a detachable bicycle ergometer. The Group I patients all underwent symptom-limited, maximal testing on the ergometer. ECG-gated SPECT data were acquired from both groups for 3 min at rest and during the last 3 min of each exercise stage. Results: Significant increases occurred in LVEF from rest to peak stress in both groups (from 55.4+/-5.8 to 66.6+/-4.1% in group N, p < 0.0001; from 49.0+/-12.8 to 56.7+/-13.8% in Group I, p < 0.001). The LVESV values significantly decreased to peak stress in Group N (from 49.9+/-13.1 to 37.8+/-10.0 ml, p < 0.0001), whereas LVEDV did not change (from 110.6+/-18.9 to 112.0+/-19.0 ml). In contrast, the LVESV values at rest and under peak stress were similar in Group I (from 52.6+/-23.9 to 51.7+/-31.4 ml) and LVEDV in Group I at peak exercise tended to increase (from 102.8+/-36.7 to 111.3+/-39.0 ml). The changes in LVESV from rest to peak stress were significantly different between Groups N and I(-12.1+/-6.3 vs. -0.9+/-11.6 ml, p < 0.02). Conclusion: ECG-gated SPECT with short-time data collection can assess left ventricular function during exercise and may offer useful information for evaluating patients with ischemic heart disease.