Stem Cell to Repair Heart Tissue After Heart Attack

According to this website http://www.emaxhealth.com/93/8199.html, doctors in the U.K. have been testing stem cells for possible heart tissue repair after a heart attack. This procedure uses the patients own stem cell extracted from his/her spine thus elimating the ethical complications common in today's stem cell research field. According to their prelimanary finds. Patients with the injected stem cells have a much healther life after a heart attack. I find this interesting in that doctors are able to extract the stem cell from the patient instead from other sources. I'm also curious as to how this procedure actually works. All the article talked about was that stem cells were injected to the patient's hear and that these patients have suffered far less complications afterwards. How does this actually work? Does the stem cell automatically intergrate into heart tissue and begin the repairing process? What side effect would this procedure have on the patient when extra stem cell are taken away from the spine? How is that going to affect the patients other bodily functions? There are still so much that we don't know yet. I really want to see the end conclusion of this study.