Initial Data Presented on First Pacemaker Designed for Safe Use in MRI Systems

Initial safety and efficacy data have been compiled on a pacing system, which showed promise as a potential solution for patients receiving their first pacemaker and requiring a magnetic resonance imaging (MRI) scan.

The data were presented in September 2008 at the European Society of Cardiology Congress In Munich, Germany, on the Medtronic, Inc. (Minneapolis, MN,USA) investigational EnRhythm MRI SureScan pacing system. Results presented showed no MRI-related complications, and no arrhythmia or asystole (absence of electrical activity in the heart) during MRI scans conducted on patients as part of a worldwide clinical study. Moreover, other study endpoints showing that the heart responded appropriately to the level of electrical stimulation it received from the device were met. A small number of patients experienced implant complications consistent with rates for other pacemaker implant procedures, but none were related to the MRI technology.

The trial is a prospective, randomized, controlled, unblinded, multicenter study, involving 470 individuals; eligibility is based on the clinical indication for pacemaker implantation and a willingness and ability to undergo elective MRI scanning. All patients in the trial will receive an investigational EnRhythm MRI SureScan pacing system (consisting of the dual chamber EnRhythm MRI SureScan pacemaker and CapSureFix MRI SureScan pacing leads, model 5086 MRI), and two-thirds of the participants will receive MRI scans; the first MRI scans will occur approximately two to three months after device implant. The study will compare the electrical system performance, among patients in both groups. In addition, the study will assess the MRI-related complication rates in the month following the MRI scans. The expected study duration and follow-up time is approximately 30 months.

"MRI is unmatched and irreplaceable in the diagnosis of cancer and neurological disorders,” said Prof. Dr. Torsten Sommer, chief of the cardiovascular section of the radiology department, University of Bonn (Germany), and European lead radiology investigator for the clinical trial. "And for investigation of the brain and spinal cord, there is simply no suitable alternative in most cases. As the necessity for MRI grows, it is critical to introduce a solution that allows pacemaker patients safe access to MRI.”

"These data are promising,” continued Prof. Sommer. "While the trial is ongoing, we've observed no lead-performance issues or unexpected MRI effects in this patient group to date.” The clinical trial will include up to 470 patients at 53 centers in Europe, the Middle East, Canada, and the United States.

"Pacemaker technology has extended the lives of millions of patients since Medtronic founder Earl Bakken invented the first battery-operated pacemaker more than 50 years ago,” said Pat Mackin, senior vice president, Medtronic, and president of the Cardiac Rhythm Disease Management business. "Today we are building pacemakers and other devices from the ground up to ensure they meet the increasingly complex medical needs of today's patients.”

Approximately two million Europeans have implanted pacemakers, but these patients are prohibited from receiving MRI scans, a widely practiced diagnostic method for many common diseases and conditions, because their device could interact with MRI machines, potentially affecting the device or patient safety. According to Medtronic estimates, up to 50% of patients worldwide with implanted cardiac devices are expected to need an MRI scan during the lifetime of their devices.

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