This experiment showed the safety and antiarrhythmic effect of human bone marrow-derived CD271+ MSC. This was performed in immune deficient mice (Rag2-/-γc-/--mice) with electrocardiogram monitoring through Implantation of telemtry system. The induction of ventricular arrhythmias has been achieved via a permanent re-infarction through left anterior descending artery (LAD) ligation one week after a 30-minute ischemia-reperfusion. The time between 2 infarctions gave the stem cells the required period to entgraft themselves after their intramyocardial injection with the first infarction.