Metformin to Reduce Heart Failure After Myocardial Infarction

In this trial, the investigators will evaluate the effect of metformin therapy following ST-elevation myocardial infarction (STEMI) in a total of 380 non-diabetic patients. This trial is a randomized, double blind, controlled trial. The intervention, which consist of metformin 500mg twice daily or placebo twice daily, will commence within three hours after the percutaneous coronary intervention, and will be continued for 4 months. The primary endpoint is the difference between the two intervention groups (metformin vs placebo) in left ventricular ejection fraction, as measured with magnetic resonance imaging after 4 months. The investigators hypothesize that metformin therapy results in a significantly higher ejection fraction in this population.

Inclusion criteria

• The diagnosis acute MI defined by chest pain suggestive for myocardial ischemia for at least 30 minutes, the time from onset of the symptoms less than 12 hours before hospital admission, and an ECG recording with ST- segment elevation of more than 0.1 mV in 2 or more leads.
• Successful primary PCI (post-procedural TIMI 2/3);
• At least one stent sized ≥ 3.0 mm;
• Eligible for 3T CMR imaging;
• Verbal followed by written informed consent.

Exclusion criteria

• rescue PCI after thrombolytic therapy;
• need for emergency coronary artery bypass grafting;
• creatinin >177 μmol/L measured pre-PCI;
• Younger than 18 years;
• Mechanical ventilation;
• Diabetes;
• Prior myocardial infarction;
• Contra-indication to metformin (see safety);
• The existence of a life-threatening disease with a life-expectancy of less than 6 months.