A sterile, battery-powered, hermetically-sealed pulse generator impregnated with a steroid (e.g., dexamethasone) intended to be implanted with a catheter, via transvenous access, into the right ventricle (i.e., single-chamber pacing) of an arrhythmic heart to generate/conduct electrical impulses to improve cardiac output. It contains sensors to detect changes in the body (e.g., motion, breathing frequency) and to adjust the pacing rate accordingly (rate-responsive). Wireless telemetry with external devices enables programming adjustments and may allow on-going heart monitoring; it does not provide defibrillation therapy. Disposable devices associated with implantation may be included.