[What thrombolytic rate can be realized in acute myocardial infarct? Results of the Oltner Heart Emergency Study].

BACKGROUND

Despite the benefits of thrombolytic therapy, there is evidence that not all suitable patients are receiving it. Early and accurate recognition of the ECG changes of myocardial infarction is a prerequisite for effective thrombolytic treatment.

METHODS

During the Olten Heart Emergency Study we prospectively evaluated 951 consecutive patients with symptoms suggestive of myocardial infarction who were cared for by the emergency networks connected with Olten Cantonal Hospital.

MAIN OUTCOME MEASURES

The final diagnosis was myocardial infarction in 173 patients (18.2%). Diagnostic ST-segment elevation was found in 48.6% and complete left bundle branch block in 13.9% of these patients, representing a total of 62.5% acute myocardial infarction patients eligible for thrombolysis based on the ECG findings. Using a time limit of 6 hours between onset of symptoms and hospital entry for small and medium-size myocardial infarctions and 12 hours for large infarctions, plus an age limit of 70 years for inferior and 75 years for anterior infarctions as exclusion criteria for thrombolysis, we found one or more contraindications for the use of thrombolytic therapy in 50.9% of these patients. The most prevalent contraindication was time delay in the prehospital phase in 38.2%, followed by advanced age in 34.5%. Medical contraindications to thrombolytic treatment were found to be present in only 10.9%. Extension of the prehospital time delay to 24 hours would have increased the candidates for thrombolytic treatment to 39.3%, and raising the upper age limit by 5 years would have increased them to 46.8%.

CONCLUSIONS

Our figures for a theoretically adequate thrombolysis rate contrast with many previous studies and the clinical reality in different hospitals both in Switzerland and around the world. In view of the importance and socioeconomic consequences of thrombolytic treatment in myocardial infarction, studies focusing on possible reasons for discrepancies between guidelines for thrombolytic therapy and their implementation in hospital practice would appear to be a necessity in providing measures to improve patient care in this clinical setting.