A biocompatible medical device can be at least partially implantable into a living human or animal subject to provide active treatment of biofilm that can occur use within the subject. The medical device can include a catheter, including an interior conduit capable of permitting fluid flow. A heating device can be located on a portion of the catheter to be located within the subject, the heating device including at least a pair of electrodes having a variable spacing therebetween, the variable spacing specified to allow heat to be generated using a time-varying electromagnetic input signal providing a variable frequency to control a variable location along the electrodes at which heat is generated, such as can provide a virtual matrix of local heat sources.