Circulation, Vol 87, 1840-1849, Copyright © 1993 by American Heart Association
Myocardial infarct size can be estimated from serial plasma myoglobin measurements within 4 hours of reperfusion
T Yamashita, S Abe, S Arima, K Nomoto, M Miyata, I Maruyama, H Toda, H Okino, Y Atsuchi and M Tahara
First Department of Internal Medicine, Faculty of Medicine, Kagoshima University, Japan.
BACKGROUND. An early estimation of infarct size is useful for the
appropriate early treatment of patients with acute myocardial infarction.
We evaluated how early and how accurately infarct size could be estimated
from serial plasma myoglobin (Mb) measurements in patients with successful
reperfusion. METHODS AND RESULTS. We measured plasma Mb and creatine kinase
(CK) in 35 patients in whom reperfusion therapy was successfully performed.
Blood samples were collected at 15- minute intervals for 2 hours after
reperfusion, at 30-minute intervals for the subsequent 2 hours, and at
3-6-hour intervals until 52 hours after reperfusion. Plasma Mb was measured
by a newly developed turbidimetric latex agglutination assay. Total Mb and
CK release (sigma Mb, sigma CK) were calculated with a one-compartment
model. The mean chord motion in the most hypokinetic 50% of the
infarct-related artery territory was calculated from follow-up
ventriculograms as an index of the severity of regional hypokinesis. There
were significant correlations between sigma Mb and sigma CK (r = 0.89),
between log sigma Mb and the severity of regional hypokinesis (r = -0.85),
and between log sigma CK and the severity of regional hypokinesis (r = -
0.74). The time required for the cumulative Mb release curves to reach a
plateau was 64 +/- 28 minutes. An additional 53 +/- 14 minutes was required
to calculate the disappearance rate constant of Mb, and 15 minutes was
necessary for the assay. Therefore, the total time required for sigma Mb to
be available was 132 +/- 40 minutes, significantly shorter than the time
required for sigma CK, 24.3 +/- 9.1 hours (p < 0.001). The infarct size
could be estimated from the sigma Mb in 34 of 35 patients within 4 hours of
reperfusion. CONCLUSIONS. Infarct size can be estimated accurately 4 hours
after reperfusion by calculating the sigma Mb in patients with successful
reperfusion.