The purpose of this study is to determine the effects of Nitric Oxide for Inhalation on Myocardial Infarction Size.

The primary objective of the trial is to assess whether or not inhaled nitric oxide can decrease myocardial infarction (MI) size as a fraction of left ventricular size at 48-72 hours in patients presenting with an ST segment elevation MI who undergo successful percutaneous coronary intervention.

Inclusion Criteria:

1. Acute myocardial infarction (defined as an episode of chest pain or related symptom lasting greater than 2 hours but less than 12 hours and electrocardiographic evidence of ST elevation (measured as 0.08 seconds after the J point; sum greater or equal to 0.6 mV in leads I, II, III, AVL, AVF, V1-V6).
2. No evidence of congestive heart failure (no S3 or evidence of pulmonary edema) and normal oxygen saturation on ≤ 2L oxygen by NC.
3. All patients must undergo successful percutaneous coronary intervention for TIMI 0 or 1 coronary flow with resulting TIMI 2 or 3 (residual stenosis less than 30% if stented and less than 50% if opened by balloon angioplasty).
4. Age > 18 years.
5. Signed EC approved informed consent.

Exclusion Criteria:

1. Prior myocardial infarction (as determined by patient history and/or ECG), cardiac surgery, or severe pericardial, congenital, cardiomyopathic or valvular heart disease.
2. Requirement for urgent cardiac surgery.
3. Previous CABG or PCI.
4. Left bundle branch block.
5. Unable to tolerate magnetic resonance imaging (including disallowed metallic implants or BMI > 35) or unable to tolerate gadolinium contrast media, including patients with calculated creatinine clearance less than 60 ml/min/1.73 m2 BSA.
6. Active or recent hemorrhage requiring an invasive procedure for evaluation or transfusion within 6 weeks prior to presentation or hemorrhagic stroke within the 6 weeks prior to presentation.
7. Known or suspected aortic dissection.
8. Prior history of pulmonary disease requiring chronic oxygen therapy.
9. Pregnancy, lactating and woman of childbearing potential.
10. Use of investigational drugs or device within the 30 days prior to enrollment to the study. Investigational uses of approved therapies will be allowed.
11. Medical problem likely to preclude completion of the study.