Medtronic begins European and US trial of MRI-compatible pacemaker
Minneapolis, USA. Medtronic, Inc. (NYSE:MDT) has begun an international
clinical study to confirm the safety and efficacy of its EnRhythm MRI
SureScan pacing system, the first pacemaker system to be developed and
tested specifically for safe use in magnetic resonance imaging (MRI)
scanners under specified scanning conditions.
Pacemaker technology has extended the lives of thousands of patients with
heart rhythm conditions, and each year nearly one million pacemakers are
implanted in patients worldwide. While improvements to pacing technology
have continued since its development nearly 50 years ago, this advance marks
a concerted effort to pursue compatibility with MRI scans, an important
healthcare diagnostic for many conditions.
“For important safety reasons, regulatory agencies worldwide prohibit
individuals with implantable cardiac devices from receiving MRI scans,” said
Steve Mahle, president of the Cardiac Rhythm Disease Management business at
Medtronic. “Medtronic has thoroughly researched the risks to patients and
designed a pacemaker and lead system from the ground up that we expect will
help many, many patients take advantage of the benefits of MRI technology.”
The EnRhythm MRI SureScan pacing system consists of the new dual-chamber
EnRhythm MRI SureScan pacemaker and CapSureFix MRI SureScan pacing leads
The first clinical trial devices were recently implanted in Europe by
Prof. Dr. Firat Duru, University Hospital in Zürich, Switzerland; Dr. Helmut
Pürerfellner, Elisabethinen Hospital in Linz, Austria; Dr. Gijsbert De
Ruiter, Onze Lieve Vrouwe Gasthuis in Amsterdam, The Netherlands; and Dr.
Stefan Spitzer, Praxisklinik Herz und Gefässe in Dresden, Germany.
trial, a prospective, randomized controlled, unblinded, multi-centre study,
is planned to occur at hospitals in Austria, Belgium, Canada, Denmark,
France, Germany, Italy, Netherlands, Switzerland, United States, and United
Kingdom; procedures are expected to begin outside Europe later in the year.
Approximately 350 individuals will participate in the study, and 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 EnRhythm MRI SureScan pacing system, and
approximately half of the participants will receive MRI scans; the trial’s
first MRI scans will occur approximately two to three months after device
implant. The study will compare the electrical and diagnostic system
performance, as well as complication rates, among patients in both groups.
The expected study duration is approximately 24 months.
“We see patients
every week who aren’t able to get an MRI scan to determine the cause of a
clinical issue and must use less effective diagnostic methods because they
have a pacemaker,” said Prof. Dr. Richard Sutton, cardiologist in the Royal
Brompton Hospital in London and European lead cardiology investigator for
the EnRhythm MRI SureScan Pacing System Clinical Study. “The ability to
perform MRI scans is a critical medical need, especially as the number of
people who get medical devices increases; Medtronic’s new pacing system is
designed to meet this need by enabling pacemaker patients to receive MRI
“MRI safety is an important issue,” 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. “It is critical to protect patients from electromagnetic fields that
could contribute to a loss of pacing therapy. The only sure way to do this
is to study a pacing system that was designed specifically for use in MRI
The EnRhythm MRI SureScan pacemaker includes modified hardware to minimize
the level of energy transmitted through the lead/device connection point.
The pacemaker also includes a new SureScan feature that can be programmed
“on” before an MRI scan to eliminate the impact of MRI-generated electrical
noise, which can prevent necessary pacing therapy or cause the device to
oversense and deliver unnecessary pacing therapy. When the SureScan feature
is on, the device’s data collection and monitoring functions are temporarily
suspended, while allowing the device to continue providing asynchronous
pacing if needed. The device and leads also contain radiopaque marks,
viewable via X-ray, to indicate that the system is MRI-compatible.
The pacemaker incorporates all diagnostic and therapeutic features of the
commercialized Medtronic EnRhythm pacemaker, including an exclusive pacing
mode called MVP or Managed Ventricular Pacing, which enables the device to
be programmed to deliver pacing pulses to the right ventricle only when
necessary. MVP has been shown to reduce unnecessary right ventricular pacing
by 99% (median value). Recent clinical studies have suggested that reducing
this pacing stimulation may reduce the patient’s risk of developing heart
failure and atrial fibrillation, a potentially life-threatening irregular
The CapSureFix MRI SureScan leads are modified versions of the
active-fixation Medtronic CapSureFix Novus leads, the most-prescribed lead
in the history of pacing. Leads are insulated wires that carry precisely
timed electrical impulses from the pacemaker in the patient’s chest to a
specific point on the inner heart wall. Available in three lengths, the
atrial and ventricular CapSureFix MRI SureScan leads are designed with
modified internal wiring composition to decrease the risk of overheating
during an MRI scan without limiting the ability to conduct therapy.