Serum myoglobin determinations in the assessment of acute myocardial infarction.

Abstract

Serum myoglobin (SMb) changes following acute myocardial infarction were studied in 67 patients admitted to the coronary care unit soon after the onset of symptoms (mean delay 2.8 ± 2.2 h; CK on admission < 150 iu/l). A typical rise and fall of SMb concentrations was seen in all cases. The maximum SMb level (718 ± 301 ng/ml) was reached 7.2 ± 3.7 h after admission. Return to values lower than 80 ng/ml was observed after a mean time of 36.2 ± 20.9 h. SMb peak concentration correlated significantly with both serum enzyme peak level and cumulated CK activity (r=0.64, P < 0.0001). The myoglobin release patterns were recorded in 121 patients. The twenty-four patients whose SMb levels remained higher than 100 ng/ml 48 h following admission demonstrated a higher incidence of left ventricular failure (Killip classes III and IV) and a mortality rate of 33%. Patients who died within three months following hospitalization (n=10) showed significantly more elevated myoglobin concentrations throughout the investigation period as compared to survivors (n=111). Myoglobin determined 4 h following admission correlated with serum lactate dehydrogenase activity, and high SMb levels were associated with an increased mortality rate. Our results suggest that SMb measurements might allow a stratification of patient risk as early as 9 to 12 h following the onset of myocardial infarction.