["Inappropriate" thrombolysis in suspected myocardial infarct]

Thrombolysis in patients with suspected acute myocardial infarction (MI) without increase of cardiac enzymes (i.e. creatine kinase) above the normal level is a rare phenomenon which is not well described in the literature. We studied 1.077 consecutive patients admitted to the General Hospital of Vienna who were treated for suspected acute MI with thrombolytic agents between January 1992 and December 1998. In 39 patients (3.6%) MI was ruled out on the basis of persistently normal creatine kinase (CK) levels. By means of chart review and database inquiry 28 (72%) of these patients were finally diagnosed as having an acute coronary syndrome (coronary group); 11 patients (non-coronary group) had other diagnoses (pericarditis in 5 cases). Comparison of the coronary vs. the non-coronary group showed no differences in risk factors, in the history of cardiac events and vital signs at the time of admission. Statistically significant differences were found in age [61 (IQR 50-70) years in the coronary group vs. 47 (IQR 47-55) years in the non-coronary group, p = 0.009], in gender distribution (p = 0.007), in the ST-depression score [4 (IQR 1-5) mm vs. 0 (IQR 0-0) mm, p < 0.0001], in the difference between highest CK level and CK level at admission [21 (IQR 8-35) U/I vs. 0 (IQR 0-0) U/I, p < 0.0001] and in the time difference from admission to highest CK level [6 (IQR 3-10) hours vs. 0 (IQR 0-0) hours, p < 0.0001]. A trend towards more complications, i.e. pulmonary congestion, bradycardia, ventricular taycharrhythmia and in-hospital mortality (21% vs. 0%, p = 0.09) was found in the coronary group. The relatively low number of patients with "unjustified" thrombolysis does not justify the need for a change in criteria for thrombolysis. Patients of the non-coronary group may be identified by a lack in ST-depression. Moreover, patients of the coronary group may have benefitted from thrombolysis by prevention of myocardial damage.