Techniques are disclosed for using a cardiac signal sensed via a plurality of electrodes disposed on one or more leads implanted within an epidural space of a patient to control spinal cord stimulation (SCS) therapy. In one example, an implantable medical device (IMD) senses an electrical signal via a plurality of electrodes disposed on one or more leads implanted within an epidural space of a patient. Processing circuitry determines, from the electrical signal, one or more cardiac features indicative of activity of a heart of the patient. The processing circuitry controls, based on the one or more cardiac features, delivery of SCS therapy to the patient.