Comparison of post-exercise and post-vasodilator stress myocardial stunning as assessed by electrocardiogram-gated single-photon emission computed tomography.
BACKGROUND
Exercise gated single-photon emission computed tomography (SPECT) using technetium-99m (99mTc)-sestamibi evaluates both myocardial perfusion during stress and wall motion >30 min after the stress, which has the potential to assess not only exercise-induced myocardial ischemia but also the development of myocardial stunning.


RESULTS
To evaluate the incidence of post-stress myocardial stunning, as well as comparing the effects of different stress methods on the development of stunning, 179 consecutive patients with known or suspected coronary artery disease (CAD) underwent (99m)Tc-sestamibi SPECT with either exercise (n=135) or adenosine triphosphate disodium (ATP) (n=44). Electrocardiogram-gated SPECT images were acquired >30 min after the stress and again 4 h later, and perfusion and wall motion were evaluated. Post-stress myocardial stunning occurred in 24 patients (13%): 22 after exercise and 2 after ATP stress. The magnitude of the transient wall motion abnormality after exercise was greater in patients with severe ischemia, compared with those with mild-to-moderate ischemia (p<0.0001). By contrast, with ATP stress, the magnitude of the transient wall motion abnormality was similar, regardless of the severity of perfusion abnormality. Furthermore, a significant correlation between summed difference score and transient wall motion abnormality was found after exercise (r=0.68, p<0.0001). With ATP, however, no such correlation was observed (r=0.28, p=NS).


CONCLUSIONS
Using 99mTc-sestamibi gated SPECT, myocardial stunning is frequently observed after exercise and correlates with the severity of myocardial ischemia, but this does not occur with ATP, which is regarded as a specific marker for severe CAD.
Tanaka
Hirokazu
H
Department of Internal Medicine II/Cardiology, Tokyo Medical University, Tokyo, Japan. htanaka7@tokyo-med.ac.jp
Chikamori
Taishiro
T
Hida
Satoshi
S
Usui
Yasuhiro
Y
Harafuji
Katsufumi
K
Igarashi
Yuko
Y
Yamashina
Akira
A
D000255:Adenosine Triphosphate / Q000008:administration & dosage; D000368:Aged; D003327:Coronary Disease / Q000150:complications / Q000000981:diagnostic imaging*; D004562:Electrocardiography / Q000379:methods; D005080:Exercise Test / Q000009:adverse effects; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017682:Myocardial Stunning / Q000000981:diagnostic imaging* / Q000209:etiology; D011859:Radiography; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
D019275:Radiopharmaceuticals; D000255:Adenosine Triphosphate; D017256:Technetium Tc 99m Sestamibi