The predictive value of cumulative lactate dehydrogenase release within the first 72 h of acute myocardial infarction in patients treated with primary angioplasty.

BACKGROUND In patients with acute myocardial infarction, estimation of infarct size by cumulative lactate dehydrogenase release at 72 h (LDHQ(72)) 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 (LV(ef)) 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 (LDHQ(72)<800 U/L), medium (LDHQ(72) 800-2500 U/L) or large (LDHQ(72)>2500 U/L) myocardial infarction. RESULTS LDHQ(72) was closely correlated with LDHQ(60), LDHQ(48) and LDHQ(36) (r = 0.998, 0.993 and 0.987, respectively, P <0.0001). The relations between LDHQ infarct size classification and mean LV(ef) (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 LDHQ(36) is an objective and widely available method for early risk stratification in patients treated with primary angioplasty for acute ST-segment elevation myocardial infarction.