Embodiments of the invention are related to medical devices filled with a liquid composition, amongst other things. In an embodiment, the invention includes a hermetically sealed housing defining an interior volume, a component module disposed within the interior volume, the component module comprising a circuit board, the component module displacing a portion of the interior volume. A liquid composition can be disposed within the housing, the liquid composition filling at least 80% of the interior volume not displaced by the component module. Other embodiments are also included herein.