They broke these up, in order to extract cardiacstemcells from them (these cells can be identified by the presence on their surfaces of a particular protein), and then bred the stemcells in tissue cultures until they numbered millions.
The long-term hope is to treat patients with some sort of stem cell that could turn into beating heart muscle and replace dead cardiac tissue with fully functioning new cells.
Bolli has refined his procedure to make it less invasive -- stemcells can now be taken through a catheter -- and none of the patients in cardiacstem cell trials have suffered serious adverse effects.