A therapy electrode system comprises a garment configured to be worn about a torso of a patient, a therapy electrode disposed in the garment and configured to deliver one or more electrical shocks to a body of the patient, a replaceable gel cartridge disposed on the therapy electrode and configured to release a conductive gel onto the patient's skin at an interface between the therapy electrode and the patient's skin prior to the delivery of the one or more electrical shocks to the body of the patient at the interface between the therapy electrode and the patient's skin, and a fluid pump in fluid communication with the replaceable gel cartridge.