Objective: Although post-ischemic stunning has emerged as an important marker for severe coronary artery disease (CAD), differences in stress methods may have different effects on left ventricular (LV) volumes and function.
Methods: To assess differential effects comparing exercise and pharmacologic stress on the LV measurements, (99m)Tc-sestamibi gated single-photon emission computed tomography (SPECT) acquired more than 30 min after stress and at rest was evaluated in 38 patients undergoing adenosine triphosphate (ATP) stress (ATP group) and 38 age-and sex-matched patients subjected to exercise stress (Ex group) among 268 patients with normal SPECT findings.
Results: Coronary risk factors and LV volumetric measurements at baseline were similar in the two groups. Compared with volumetric measurements at rest, end-diastolic volume (EDV) increased (72 +/- 21 ml to 74 +/- 21 ml; P = 0.01), end-systolic volume increased (25 +/- 12 ml to 28 +/- 13 ml; P = 0.001), and ejection fraction (EF) decreased after stress (66% +/- 8% to 63% +/- 9%; P < 0.002) in the ATP group. In the Ex group, by contrast, no such change was observed. In addition, changes in EDV (3 +/- 6 vs. -1 +/- 5 ml; P = 0.01) and the stress-to-rest ratio of EDV (1.04 +/- 0.09 vs. 0.99 +/- 0.08; P < 0.02) after stress were greater in the ATP than in the Ex group.
Conclusions: Differential effects of stress methods on LV volumes persist more than 30 min after the stress. These findings should be kept in mind when interpreting post-ischemic stunning.