Serum myoglobin in myocardial infarction: the "staccato phenomenon." Is acute myocardial infarction in man an intermittent event?

When serum was sampled frequently and soon after acute myocardial infarction, myoglobinemia was extremely common, occurring in 12 of 13 selected patients. Myoglobin first appeared in the serum within a few hours after infarction, but not consistently earlier than creatine phosphokinase. The peak level of serum myoglobin was reached appreciably earlier than the peak values of serum creatine phosphokinase activity. Time of earliest myoglobin appearance in the serum, peak level of myoglobin measured, and duration of detectable myoglobin release all correlated poorly with clinical and biochemical estimates of severity of myocardial infarction. There was no correlation between myoglobin levels and infarct size as estimated from creatine phosphokinase kinetics. Myoglobin appeared in the serum in multiple short "staccato" bursts, or episodes, often lasting only one to two hours. The hypothesis is suggested that the pattern of myoglobin appearance is a reflection of the episodic nature of acute myocardial infarction. Although isolated myoglobin determination may not be useful at present, for quantification of total myocardial damage, its pattern of release may be a sensitive marker for studying the time course of infarction, and may be useful to evaluate therapeutic interventions designed to interrupt an ongoing syndrome of myocardial necrosis.