Inclusion Criteria:  Age >18 years. Anterior STEMI. Symptom duration ≤6 hours  Written informed consent obtained - Angiographic Inclusion criteria:  Culprit lesion in LAD, major branch of LAD, proximal or mid LCx or proximal or mid RCA  TIMI flow ≤2 in the culprit vessel  -Echocardiographic inclusion criteria:  Detectable hypo- or akinesia corresponding to ≥5% of the left ventricle corresponding to culprit lesion, per bedside visual assessment.  Exclusion Criteria:  Previous randomization in the study  Any of the following contraindications for treatment with adenosine:  Known pre-existing atrioventricular block grade ≥2 or sick sinus syndrome in patients without pacemaker. Known pre-existing elevation of intracranial pressure Treatment with dipyridamole within 24 hours of randomization Systolic blood pressure <80 mm Hg at screening Any concomitant condition resulting in a life expectancy of less than one month Previous myocardial infarction or other cardiac condition resulting in impaired regional or global systolic function without documented recovery of cardiac function Heart transplant or left ventricular assist device recipient Not suitable in the opinion of the investigator due to severe or terminal comorbidity with poor prognosis or characteristics that may interfere with adherence to the trial protocol Pregnancy or woman of childbearing potential who is not sterilized or using a medically accepted form of contraception -