Acute Myocardial Infarction Management

Thrombolysis Indications and Contraindications

The American College of Cardiology recommends thrombolysis for STEMI when primary PCI cannot be performed within 120 minutes of first medical contact, provided the patient has symptoms within 12 hours of onset and no contraindications to fibrinolytic therapy 1, 2
Indications for thrombolysis based on ECG include ST elevation ≥0.1 mV in at least 2 contiguous precordial leads or 2 adjacent limb leads, new or presumably new left bundle branch block, and true posterior MI with ST depression in anterior leads 1, 2, 3
Contraindications for thrombolysis based on ECG include ST depression only, except when true posterior MI is suspected or when associated with ST elevation in lead aVR, and non-diagnostic ECG changes without clear ST elevation 1, 3

If symptom onset is less than 12 hours, primary PCI is preferred if available within 120 minutes of first medical contact; otherwise, administer thrombolysis within 30 minutes of first medical contact 1, 2
If symptom onset is between 12-24 hours, consider thrombolysis if PCI is unavailable and the patient has ongoing ischemic symptoms and a large area of myocardium at risk or hemodynamic instability 1, 3
Thrombolysis is not indicated if symptom onset is more than 24 hours 3

Select a fibrin-specific agent, such as tenecteplase, reteplase, or alteplase, for thrombolysis 1, 2
Tenecteplase is administered as a single IV weight-based bolus, while reteplase is given as 10 U + 10 U IV boluses 30 minutes apart, and alteplase is administered as a 90-minute weight-based infusion 1, 2

Transfer patients to a PCI-capable center immediately after fibrinolysis 2
Perform emergency angiography and PCI if fibrinolysis has failed, or if hemodynamic or electrical instability develops, or if worsening ischemia occurs 2
If fibrinolysis is successful, perform angiography between 2-24 hours after 2

The mortality benefit of thrombolysis is time-dependent and most effective when administered within the first 1-2 hours of symptom onset 1

Do not administer thrombolytics to patients with only ST depression, unless posterior MI is suspected 1, 3
Do not delay thrombolysis when PCI cannot be performed within the recommended timeframe 1, 2
Do not overlook contraindications to thrombolysis, such as prior intracranial hemorrhage, recent stroke, or active bleeding 4
Do not forget to transfer patients to a PCI-capable center after thrombolysis for potential rescue PCI 2