To the Editor.
—We read with great interest the article by Irvin et al in the Archives (1980;140:329-334) concerning the biochemical indicators creatine phosphokinase (CPK) and isoenzyme MB CPK and their relationship to the onset of symptoms in the acutephase of myocardial infarction.However, we would like to comment on the number of samples of MB CPK that should be taken for diagnosing myocardial infarction and on the difficulties in choosing the optimal hour for sampling. Based on a recent study of ours (unpublished data) of 15 patients with definite acute myocar dial infarction in whom frequent blood samples were drawn for determining MB CPK and serum myoglobin values in the acute phase of the infarction (15 samples during the first 24 hours for each patient), it was demonstrated that all values of MB CPK were definitely elevated (above 6%) during the interval between nine to 20 hours from
Grenadier E, Keidar S, Alpan G, Palant A. Acute Myocardial Infarction and MB Creatine Phosphokinase. Arch Intern Med. 1981;141(11):1556-1557. doi:10.1001/archinte.1981.00340120164044