The present application relates to an implantable device configured to be placed in a stomach of a patient to elevate with increased stomach contents and stimulate the cardia of the stomach, the device comprising: an inflatable body generally in the shape of a prolate spheroid defining a longitudinal axis between end poles and an equatorial plane, the inflatable body having an exterior surface with alternating longitudinal ribs and channels to facilitate passage of food therearound an internal tube mounted within the inflatable body extending between the end poles, the internal tube being formed of a material that is stiffer than the material of the inflatable body and at least one fill valve mounted to one end of the internal tube for injecting air or an inert gas into an inner chamber of the inflatable body, wherein the implantable device is configured for insertion in the stomach with the inflatable body deflated and collapsed around the internal tube, and configured for implant in the stomach with the inflatable body inflated at least partly with air/inert gas for flotation on the contents of the stomach such that one of the end poles contacts the cardia when the device elevates within the stomach from an increase in the contents therein.
