Enzyme Profiles in Pulmonary Infarction

To the Editor:— In reply to the letter of Dr. Stead, our studies have indicated that the CPK and HBD were primarily elevated in patients with myocardial infarction. We indicated that the study of isoenzymes in general was not of value in distinguishing pulmonary from myocardial infarction. We also indicated that the LDH alone was often not useful since it was elevated in pneumonia, heart failure, and other diseases. Our conclusion was that in the presence of an increased LDH and clinical manifestations suggesting pulmonary infarction, the finding of a normal CPK would effectively eliminate myocardial infarction as the cause of the symptom and the finding of an elevated CPK would strongly suggest such myocardial infarction.