ECG Changes Warranting Antiplatelet and Anticoagulant Therapy

Acute Coronary Syndrome with ST-Segment Elevation (STEMI)

The European Society of Cardiology recommends initiating dual antiplatelet therapy (aspirin plus a P2Y12 inhibitor) and anticoagulation immediately when the ECG shows ST-segment elevation or new left bundle branch block (LBBB), as these findings indicate acute myocardial infarction requiring urgent reperfusion therapy 1, 2
Aspirin should be administered immediately at 150-300 mg oral loading dose (or 75-250 mg IV if unable to take orally), followed by 75-100 mg daily maintenance, in patients with STEMI 1, 2
A P2Y12 inhibitor, such as ticagrelor 180 mg loading dose, then 90 mg twice daily, or prasugrel 60 mg loading dose, then 10 mg daily, should be given before or at the time of PCI in patients with STEMI 1, 2
Anticoagulation with unfractionated heparin (UFH), enoxaparin, or bivalirudin should be started immediately during PCI in patients with STEMI 1, 2

Aspirin should be administered at 150-300 mg loading dose, followed by 75-100 mg daily maintenance, in patients with NSTE-ACS 1
A P2Y12 inhibitor, such as ticagrelor 180 mg loading dose, should be initiated as soon as diagnosis is established in patients with NSTE-ACS 1
Anticoagulation with UFH, enoxaparin, or fondaparinux should be selected based on bleeding and ischemic risk in patients with NSTE-ACS 1

The European Society of Cardiology recommends continuing dual antiplatelet therapy for 12 months unless excessive bleeding risk exists (PRECISE-DAPT score ≥25), in which case consider stopping at 6 months 1, 2
Anticoagulation should be discontinued immediately after PCI procedure 1
For patients with high ischemic risk and low bleeding risk, dual antiplatelet therapy may be continued beyond 12 months 1
The American Heart Association recommends that patients already on warfarin who present with ACS should not initiate additional anticoagulation until INR <2.0, but start antiplatelet therapy immediately even if therapeutically anticoagulated 3