Abstract: Ischemic heart disease is a life threatening condition whose prognosis remains poor as current treatments are palliative and the loss of cardiac tissue is not restored. Stem cell therapy appears to be a promising option for myocardial repair after myocardial infarction (MI). Recent experimental and clinical work has suggested that stem cell therapy contributes to cardiac regeneration and improve myocardial function. Unfortunately, there is still a lack about important issues such as mechanism of action of stem cells, dose, long-term engraftment, route of delivery and frequency of cell administration. Also, there is a concern about proarrhythmic effect of stem cell therapy. Some studies have provided basis that stem cells can show intrinsic pacemaker function and provide areas of slowed conduction that can set the stage for arrhythmias.