Myocardial infarct size: clinicopathologic agreement and discordance

An accurate postmortem method of planimetrically estimating the extent of myocardial infarction was employed in 16 cases. Delineation of necrotic myocardium was enhanced by a macroscopic staining technique, which utilizes a tetrazolium dye. Comparison of infarct size with peak serum creatine phosphokinase levels showed a general correlation between the two that was not statistically significant. Two markedly disparate cases serve to emphasize the need for clinical awareness of the temporal relationship between myocardial infarction and creatinine phosphokinase analysis as well as the possibility of other anatomic sources of elevation of serum enzyme levels. Comparison of infarct sizes in cardiogenic shock and nonshock patients confirms the existence of a significant relationship between a larger myocardial infarct and shock. However, the data from several patients in the group again emphasize the possibility of maintaining a reasonable blood pressure in the face of a massive myocardial infarction or, more importantly, of manifesting "cardiogenic" shock when only a small amount of left ventricular damage has been sustained. The latter possibility may be related to other anatomic events, e.g., bowel infarction, hemorrhage, or possibly right ventricular ischemia, infarction, or dysfunction.