DIAGNOSTIC-VALUE OF HUMAN CARDIAC TROPONI N-I ASSAY IN ACUTE MYOCARDIAL-INFARCTION

Immunoenzymatic assay (IEMA) of human cardiac Troponin I (Tnl c) was u sed in patients admitted to the coronary care unit with acute myocardi al infarction (AMI). Tnl c was detected in all patients with AMI. The detection of Tnl c was earlier after the onset of pain (4.5 +/- 2.3 ho urs) than that of CKMB activity (6.3 +/- 3.6 hours), p = 0.003. The ki netics of Tnl c are usually monophasic and parallel to that of CKMB ac tivity. The peak value occurs 12.2 +/- 4.6 hours and 15.8 +/- 9.0 hour s after the onset of pain in patients treated by thrombolysis. The Tnl c disappears from the plasma between 5 and 9 days after the onset of pain, later than CKMB activity (p = 0.0001). In 49 patients admitted f or AMI treated by thrombolysis, the comparative sensitivities of Tnl c (threshold : 0.1 ng/ml) and of CKMB activity (threshold : 15 IU/I; CK greater than or equal to 100 UI/I) were, at the first sampling on adm ission, 61 % and 22 % respectively (p = 0.0002) (average interval from onset of pain to first blood sampling : 3.4 +/- 1.3 hours). Tnl c was not detected in the plasma of 145 normal subjects nor in any of the 6 patients with severe muscular trauma or rhabdomyolosis (specificity : 100 %). This IEMA is a specific and a sensitive method of diagnosing acute and subacute myocardial infarction. It is ideal for the detectio n of myocardial necrosis in complex clinical situations when the usual enzymatic markers may be ineffective.