Background: In patients with acute myocardial infarction, estimation of
infarct size by cumulative lactate dehydrogenase release at 72 h (LDHQ72)
is a simple and widely used method. Our objective was to study the value of
estimating infarct size, by the cumulative release of LDH over 72, 60, 48 and 36 h in
predicting left ventricular ejection fraction (LVef) and cardiac death at
1 year.
Methods: In the Zwolle Infarction Study infarct size estimated as LDHQ
was calculated in 1224 patients treated with primary percutaneous coronary
intervention for acute myocardial infarction between December 1993 and June 2001.
Patients were categorized as having small (LDHQ72<800 U/L), medium
(LDHQ72 800-2500 U/L) or large (LDHQ72>2500 U/L)
myocardial infarction.
Results: LDHQ72 was closely correlated with
LDHQ60, LDHQ48 and LDHQ36 (r =
0.998, 0.993 and 0.987, respectively, P <0.0001). The relations
between LDHQ infarct size classification and mean LVef (51% vs 45% vs 35%,
P <0.001) or cardiac death at 1 year (0-0.3% vs 0.7-1% vs
6-8%) showed a similar pattern, irrespective of whether LDH was measured up to 36,
48, 60 or 72 h.
Conclusion: Infarct size classification based on LDHQ36 is an
objective and widely available method for early risk stratification in patients
treated with primary angioplasty for acute ST-segment elevation myocardial
infarction.
