The cross-talk between spinal cord stimulators and the Confirm™ cardiac monitor

Spinal cord stimulators (SCS) function by transmission of electrical impulses to electrode contacts placed within the epidural space depending on the painful area to be treated. Because of the electrical nature of the SCS, there has been concern about the interaction between these devices and devices that monitor or augment the cardiac system. Implantable loop recorders help to identify the causes of syncope or palpitation by continuously evaluating and recording portions of an electrocardiograph in patients being evaluated for cardiac conduction arrhythmias. The purpose of the study is to simulate the possible effects of spinal cord stimulation on a Confirm cardiac monitor (St. Jude Medical, St. Paul, MN, USA).

Twenty patients without preexisting cardiac disease, who were successfully being treated with SCS, were enrolled. Confirm loop recorders (St. Jude Medical) were placed on their chest wall in a noninvasive manner, with all programmed at identical settings. Multiple stimulation settings were adjusted on the stimulators and the recordings from the Confirm loop recorder were analyzed for evidence of interference.

Fifteen of the patients had no electrical noise detected at any of the tested combinations of stimulation. Five patients had some electrical "noise" detected by the loop recorder, but it did not inhibit the cardiologist evaluating the recording from analyzing the electrocardiograph for diagnostic purposes. At no point with any of the patients at any tested setting was there an appearance of a life-threatening arrhythmia.

Our study demonstrates that spinal cord stimulation is unlikely to interfere with the data collected by the Confirm loop recorder, and the presence of an SCS should not interfere with the ability to use a loop recorder for diagnostic purposes.