Devices, systems and methods are provided for electrical stimulation of a body organ, particularly within the gastrointestinal tract. In preferred embodiments, the stomach is the organ within the gastrointestinal tract which is targeted for such stimulation. A guide wire or other delivery device is positioned within the body so as to transect the stomach wall. Devices and systems are then advanced over the guide wire for attachment to the stomach wall. The guide wire may be placed by endoscopic, open, laparoscopic or a modified percutaneous approach. In a modified percutaneous approach, the stomach is accessed without the use of general anesthesia by advancing a needle through the abdomen, transecting the stomach wall with the needle and advancing the guide wire through the needle. In some embodiments, particularly for use in obese patients, the modified percutaneous approach includes advancing a trocar through the tissue of the patient toward the outer surface of the organ and advancing the needle through the trocar prior to transecting the wall with the needle.