The study was withdrawn due to many implementation difficulties.

The study will see if mechanical impulses delivered by an echocardiographic probe during a continuous infusion of MRX 801 are capable of improving blood flow in smaller heart vessels in patients with acute coronary syndromes.

Pre-clinical studies have indicated that, during a continuous infusion of intravenous perfluorocarbon-containing microbubbles, the ultrasonic power delivered from a diagnostic ultrasound transducer is capable of restoring microcirculatory flow and improving epicardial recanalization rates following acute coronary thrombotic occlusions. Since both diagnostic ultrasound and intravenous infusions of microbubbles are a Class I indication to assess regional and global left ventricular function and risk area in patients with ST segment elevation myocardial infarction (STEMI), this pilot study will examine whether diagnostic assessments of left ventricular function and risk area size impacts epicardial recanalization rates and infarct size in STEMI.

The aim of this study is to test whether guided high mechanical index impulses from a diagnostic transducer during a continuous infusion of intravenous microbubbles are capable of improving microvascular recanalization and epicardial recanalization rates in STEMI, as assessed by coronary angiography, and recovery of regional microvascular perfusion and function in the post-infarction period.

Inclusion Criteria:

1. Male or female, age ≥ 30 years.
2. Chest Pain occurring lasting less than six hours from onset, and EKG evidence of an acute ST segment elevation myocardial infarction.
3. Arrival in the Emergency Department with above inclusion criteria between 7 am and 7pm.

Exclusion Criteria:

1. Known or suspected hypersensitivity to ultrasound contrast agent used for the study.
2. Complicated hemodynamic instability (i.e., NYHA Class IV heart failure, unstable angina at rest despite medical therapy).
3. Life expectancy of less than two months or terminally ill.
4. Heart transplant recipient, hypertrophic cardiomyopathy, severe valvular disease, acute myo- or pericarditis.
5. Contraindication to Heart Catheterization
6. Known bleeding diathesis or contraindication to glycoprotein 2b/3a inhibitors or aspirin.