[Troponin I in acute ischemic cardiopathy]

The present study was aimed at investigating cardiac troponin I values in the first week of acute myocardial infarction and in non-infarct acute coronary ischemic syndromes.

Eighty-two patients, 42 with acute myocardial infarction, 10 with stable angina and 30 with primary unstable angina, were enrolled in the study. Blood was collected within 6 hours of symptom onset and, in the group with acute myocardial infarction, after 24 and 48 hours, and on day 7.

Serum troponin I increased within the first 6 hours of myocardial infarction, reached the peak after 24 hours, at 48 hours it decreased, and remained above the normal range until day 7. However, troponin I values 1) were constantly higher in patients who died, in those > 60 years old and in those with antero-lateral necrosis than in survivors, in those < 60 years old and in those with infero-posterior necrosis, respectively; 2) returned to normal range on day 7 in survivors and in patients with infero-posterior acute myocardial infarction; 3) were significantly higher in fibrinolysed patients than in those who did not undergo thrombolysis; 4) were higher in patients classified as Killip class > 2. Serum troponin I values were in the normal range in non-infarct acute coronary ischemic syndromes, but were higher in unstable than in stable angina.

The lesser increase and the early return to the normal range of cardiac troponin I levels in the subgroups of patients with myocardial infarction having a better clinical course could be regarded as a favorable prognostic sign. Since the persistent higher values of cardiac troponin I in fibrinolysed subjects are associated with the angiographic finding of patent coronary arteries, it can be suggested that the large and persistent post-thrombolysis release of cardiac troponin I from the myocardium represents a biochemical marker of a successful reperfusion. The persistent high cardiac troponin I values in patients with advanced Killip class suggest that the neuropeptide is an index of ongoing myocyte injury and hemodynamic impairment as well. The higher values of cardiac troponin I in unstable angina are probably due to focal areas of myocardial necrosis undetectable by conventional enzymatic serum markers.