What is an indication for fibrinolytic therapy in acute myocardial infarction?

Fibrinolytic therapy is indicated in acute myocardial infarction when there is evidence of ST elevation in at least two contiguous leads on an electrocardiogram (ECG), particularly when this is observed within 12 hours of symptom onset. This ST elevation indicates a significant occlusion in a coronary artery, suggesting that the myocardial tissue is at risk. The timely administration of fibrinolytics can help dissolve the clot and restore blood flow, reducing the extent of damage to the heart muscle.

The emphasis on the duration of symptoms being less than 12 hours is critical, as the effectiveness of fibrinolytic therapy is greatest when administered early in the course of myocardial infarction. If treatment is delayed beyond this window, the potential for salvaging the heart tissue diminishes, and the risks associated with fibrinolytics may outweigh the benefits.

In contrast, other options do not meet the established criteria for fibrinolytic therapy. Angina lasting longer than 30 minutes may raise suspicion for myocardial infarction but does not fulfill the specific criteria for treatment. Similarly, the presence of Q waves typically reflects prior myocardial infarction and does not indicate a current acute event that would benefit from fibrinolytics. Lastly, chest pain that resolves spontaneously may suggest either a less severe