“…After an infarct it first appears in the plasma within four hours (Roberts et al, 1977) and reaches a peak at between J6 and 24 hours (Wagner et al, 1973); the levels fal1 to normal after 48 hours (Roe et al, 1972). Plasma activity remains low after cardioversion (Konttinen and Somer, 1973), coronary angiography (Wagner et al, 1973), pulmonary embolus (Somer and Konttinen, 1972), angina pectoris (Wolf and Kearns, 1974), arrythmias or pericarditis (Fiolet et al, 1977), intramuscular injection (Rao et al, 1975;Roberts et al, 1975;Ahumada et al, 1976), or exercise (Kaman et al, 1977). CK-MB activity is detectable in normal plasma, but only at low activity, and the conditions other than myocardial infarction (MI), in which it is significantly increased, such as Duchenne muscular dystrophy (Konttinen and Somer, 1973), crush injury (Wilhelm and Todd, 1977), and acromegalic myopathy (Wolf and Griffith, 1978), are not usually considered in the differential diagnosis of Ml.…”