Inclusion Criteria- Women must not be of child-bearing potential (1 year post-menopausal or surgically sterile).
- Symptoms of acute MI of more than 30 min but less than 6 hours
- New persistent ST-segment elevation ≥ 1 mm in two or more contiguous electrocardiogram (ECG) leads.
Exclusion Criteria- Expected time to 1st PCI balloon inflation in the hospital, from the qualifying ECG is more than 120 minutes
- Contraindication to ticagrelor (refer to SmPC)
- Concomitant medication that may increase the risk of bleeding [e.g non steroidal anti-inflammatory drugs (NSAIDs), oral anticoagulant and / or fibrinolytics, planned or administered 24 hours before randomization]
- Any of the following conditions in the absence of a functioning implanted pacemaker: known SSS, second or third degree AVB, or documented syncope of suspected bradycardic origin.