Usefulness of gated myocardial perfusion SPECT imaging soon after exercise to identify postexercise stunning in patients with single-vessel coronary artery disease.

BACKGROUND

This study determines the value of gated single photon emission computed tomography (SPECT) imaging soon after exercise to identify patients with single-vessel disease and exercise-induced prolonged myocardial dysfunction (ie, postischemic stunning).

RESULTS

We examined 19 normal individuals and 52 patients with single-vessel disease by use of 2-day technetium 99m tetrofosmin exercise/rest gated SPECT imaging. Sequential imaging was started 10, 30, and 50 minutes after exercise. The ejection fraction (EF) values were calculated with the Cedars-Sinai program. The participants were classified as follows: group A (normal individuals, n = 19), group B (individuals with coronary stenosis without Q-wave infarction, n = 18), group C (individuals with Q-wave infarction without myocardial ischemia, n = 15), and group D (individuals with Q-wave infarction and ischemia, n = 19). The post-stress EF values at 10 minutes (69.8% +/- 9.6% and 59.8% +/- 11.8%, respectively) were higher in groups A and C than those at 30 minutes (67.6% +/- 10.2% and 57.2% +/- 11.3%, respectively) ( P < .05) but were lower in group B (61.7% +/- 9.2%) than both the 30- and 50-minute values (64.2% +/- 9.5% and 64.6% +/- 9.4%, respectively; P < .05). The EF value did not significantly change in group D.

CONCLUSIONS

Tc-99m gated SPECT imaging soon after exercise is superior to conventional late imaging to discriminate patients with single-vessel disease and postexercise stunning.