The present invention provides improved systems and methods for the minimally invasive treatment of heart tissue deficiency, damage and/or loss, especially in patients suffering from disorders characterized by insufficient cardiac function, such as congestive heart failure or myocardial infarction. In certain embodiments, a cell composition comprising autologous skeletal myoblasts and, optionally, fibroblasts, cardiomyocytes and/or stem cells, is delivered to a subjects myocardium at or near the site of tissue deficiency, damage or loss, using an intravascular catheter with a deployable needle. Preferably, the cell transplantation is performed after identifying a region of the subjects myocardium in need of treatment. The inventive procedure, which can be repeated several times over time, results in improved structural and/or functional properties of the region treated, as well as in improved overall cardiac function. In particular, the inventive therapeutic methods may be performed on patients that have previously undergone CABG or LVAD implantation.
