Medical device maker Medtronic, Inc. has provided initial safety and efficacy data on its investigational pacemaker EnRhythm MRI SureScan Pacing System as a potential solution for patients with pacemaker, with the need for an MRI at the European Society of Cardiology Congress.

Medtronics says the results of its clinical trials 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.

Additionally, its study showed 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, randomised, controlled, unblinded, multi-center 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 MRITM SureScan pacing leads, Model 5086MRI), 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.''

''This data is 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 centres 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 2 million Europeans have implanted pacemakers, but these patients are prohibited from receiving magnetic resonance imaging (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 per cent of patients worldwide with implanted cardiac devices are expected to need an MRI scan during the lifetime of their devices.

MRI lets doctors see internal organs, blood vessels, muscles, joints, tumors, areas of infection and more, without X-rays or surgery, and without exposing the patient to any ionizing radiation. The MRI machine creates a magnetic field, sends radio waves through the body, then measures the response with a computer, creating an image of the inside of the body. In many cases, MRI gives information that cannot be seen on an X-ray, ultrasound or computed tomography (CT) scan.

ASTM International is an international standards organistion that has developed a classification system for implanted and ancillary clinical devices:
MR Safe: An item that poses no known hazards in all MR environments.
MR Conditional: An item that has been demonstrated to pose no known hazards in a specified MR environment with specified conditions of use.
MR Unsafe: An item that is known to pose hazards in all MR environments.
Editor's Note: The EnRhythm MRI SureScan Pacing System safety and efficacy data was presented by Prof. Torsten Sommer on 31 August at the European Science Congress.

Caution: The EnRhythm MRI SureScan Pacing System is investigational and not currently available for sale in the United States. The device is limited by federal law to investigational use only.