The aim of the present study was to investigate the efficacy of ischemic postconditioning in acute myocardial infarction patients. The safety of patients enrolled in the study was ensured during the entire study. Over 18 years old men and women were enrolled in the study who arrived to 2 of the most acknowledged Hungarian cardiac centres due to acute myocardial infarction and fulfilled all inclusion and exclusion criteria as per protocol. Patients in the order of their arrival were assigned either to control or post conditioned groups by turns. Medical treatment of the control group was done according to standard Percutaneous Coronary Intervention (PCI) guidelines, i.e. there was no further intervention after artery opening for 8 minutes, then stenting was performed. In the post conditioned group, after reperfusion has been confirmed, the coronary artery was occluded by inflation of the stent balloon 4 times (for 1-1 minute) followed by 1-1-minute reperfusion repeatedly to induce ischemic postconditioning. Postconditioning procedure was followed by stenting as in the control group. All other interventions and treatments in both patient groups were identical according to guidelines.

Over 18 years old men and women were enrolled in the study who arrived to 2 of the most acknowledged Hungarian cardiac centres due to acute myocardial infarction and fulfilled all inclusion and exclusion criteria as per protocol. Patients in the order of their arrival were assigned either to control or post conditioned groups by turns. After closing patient enrolment, further subgrouping will be performed in case sufficient group size has been achieved as follows: (1) normal, control, (2) normal, post conditioned, (3) hypercholesterolemic, not treated with statins, control, (4) hypercholesterolemic, not treated with statins, post conditioned, (5) statin treated, control, (6) statin treated, post conditioned.

Characterisation of postconditioning is performed by the following parameters:

1. Blood tests 5 minutes before as well as 8, 60 minutes, 24 hours, and 3 months after PCI to measure nitrotyrosine, a biomarker of peroxynitrite formation (nitrosative stress) by ELISA; B-type natriuretic peptide, a biomarker of heart failure by ELISA; matrix metalloproteinase activities (MMP-2 and MMP-9) putative biomarkers of cardiac remodelling by zymography; microRNA expression pattern by sequencing and its validation by quantitative real-time polymerase chain reaction (PCR).
2. Routine laboratory tests 6, 12 and 48 hours after PCI including creatine kinase (CKMB) and cardiac troponin T (cTnT).
3. ECG immediately after recanalization and intervention after 60 and 90 minutes, then 12, 24, 36 and 48 hours later 12-lead ECG is registered.
4. Echocardiography: 48 hours after intervention, standard view to judge left ventricle segments movement disorders
5. Angiography: Blush, Syntax score, and ischemic risk zone (area at risk, AAR) are determined
6. cardiac late enhancement magnetic resonance (MR) imaging to determine infarct size

At 3-month follow-up visit the following parameters were measured: echocardiography for restitution assessment, cardiac late enhancement MR imaging to determine infarct size and cardiac function, blood sampling for above mentioned biochemical laboratory tests

Inclusion Criteria:

1. Subject must be >18 years of age
2. Myocardial infarction with elevated ST
3. Chest pain onset less than 12 hours before PCI
4. concordant ST elevation (>0,1 mV) in at least 2 ECG leads
5. Occluded main proximal or middle main coronary ('Thrombolysis In Myocardial Infarction' flow grade: 0) diagnosed with coronarography
6. Coronary opened by PCI (TIMI 2 flow grade)
7. Awake, conscious, co-operating patient, who is able to retain his breath for 10 sec
8. Signed Patient Information Leaflet and Patient Informed Consent Form

Exclusion Criteria:

1. Cardiogenic shock
2. Previous myocardial infarction in the area of the occluded coronary artery
3. Occluded coronary with visible collateral branches
4. Lack of co-operation
5. Current left or right bundle branch block (LBBB)
6. Malignant ventricle arrhythmia or atrial fibrillation
7. Killip class > 2
8. Known renal failure