Systems and methods for treating a gastrointestinal condition of a patient includes minimally invasively implanting a modular or non-modular stimulation system in a patient's treatment site. The treatment site is in or on a gastric wall and electrical stimulation is provided to the gastric wall to improve a function or pressure a lower esophageal sphincter of the patient. Electrical stimulation is provided for a short period of time and treatment efficacy is evaluated through clinical results and patient reporting. If therapy is not effective, stimulation parameters may be changed.