[Sensitivity of creatine phosphokinase in early diagnosis of myocardial infarction and improvement of the test's specificity by determination of the rate of increase of enzyme activity].

The activity of serum enzymes: creatine phosphokinase (CPK), CPK isoenzyme MB and asparagine aminotransferase--was examined every 1-3 hours after the onset of a painful attack in 68 patients with "determined" (according to the 1979 WHO classification) myocardial infarction (DMI) and 32 patients with unstable angina pectoris. The activity of all three enzymes was increased in 100% of DMI cases. The rate of enzyme activity increment (delta E/delta T) calculated for the first 3-12 hours of the disease demonstrated that absolute delta E/delta T values for CPK were significantly higher than those for other enzymes. The CPK delta E/delta T was several times as high in DMI patients as it was in patients with unstable angina. Measurement of the rate of CPK activity increment over any 6-hour interval within the first day after the painful attack is suggested as a way of further improvement of the test specificity.