An implantable medical device includes a housing forming an internal cavity, the housing defining a profile with a height and a width and further defining a thickness perpendicular to its profile. The thickness of the housing is shorter than both the height and the width of the profile of the housing. The implantable medical device further includes at least one battery within the internal cavity, at least one capacitor adjacent the battery within the internal cavity, the capacitor and the battery being located along a common plane within the internal cavity, and circuitry within the internal cavity. The circuitry extends over both the battery and the capacitor within the internal cavity such that the circuitry is in a stacked arrangement relative to the battery and the capacitor.