Mismatch of left ventricular function and infarct size demonstrated by technetium-99m isonitrile imaging after reperfusion therapy for acute myocardial infarction: identification of myocardial stunning and hyperkinesia.
Quantitation of perfusion defect size using tomographic imaging with technetium-99m-hexakis-2-methoxy isobutyl isonitrile was performed at the time of hospital discharge in 32 patients with a first myocardial infarction who underwent successful coronary reperfusion within 8 h of the onset of chest pain. Reperfusion was accomplished with thrombolysis or primary coronary angioplasty. Radionuclide angiography was performed at discharge and 6 weeks later. There was a close correlation between perfusion defect size and values for ejection fraction and regional wall motion both at discharge (r = -0.80 and -0.75, respectively) and 6 weeks later (r = -0.81 and -0.81, respectively). There was no overall group difference in ejection fraction between the value at discharge and at 6 weeks; however, five patients had a significant increase (greater than or equal to 0.08) and six had a significant decrease (greater than or equal to 0.08) in ejection fraction. In patients with a significant increase at 6 weeks, ejection fraction was significantly lower at discharge than the value predicted from perfusion defect size (0.37 +/- 0.09 measured versus 0.47 +/- 0.13 predicted, p less than 0.05) and it improved at 6 weeks to near predicted values (0.51 +/- 0.07). In patients with a significant decrease at 6 weeks, ejection fraction was significantly higher at discharge than the value predicted from perfusion defect size (0.60 +/- 0.10 measured versus 0.50 +/- 0.10 predicted, p less than 0.05) and it decreased at 6 weeks to near predicted levels (0.51 +/- 0.09). Left ventricular ejection fraction at the time of hospital discharge is a potentially misleading index of the efficacy of reperfusion therapy for myocardial infarction. In a significant minority (34%) of patients this index does not accurately reflect perfusion defect size, apparently because of the effects of myocardial stunning and compensatory hyperkinesia.
Christian
T F
TF
Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905.
Behrenbeck
T
T
Pellikka
P A
PA
Huber
K C
KC
Chesebro
J H
JH
Gibbons
R J
RJ
D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000188:drug therapy*; D015428:Myocardial Reperfusion Injury / Q000000981:diagnostic imaging*; D009570:Nitriles; D015609:Organotechnetium Compounds; D011446:Prospective Studies; D011875:Radionuclide Angiography; D017256:Technetium Tc 99m Sestamibi; D015912:Thrombolytic Therapy; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use; D016277:Ventricular Function, Left / Q000502:physiology*
D009570:Nitriles; D015609:Organotechnetium Compounds; D017256:Technetium Tc 99m Sestamibi; D010959:Tissue Plasminogen Activator