Earlier this year, the Food and Drug Administration approved the first pacemaker that can be used with an MRI scan, making these two potentially lifesaving technologies compatible for the first time.

Magnetic Resonance Imaging has become the diagnostic standard of care for a variety of ailments. An estimated 30 million MRI scans are performed in the United States each year. MRI is safe with no serious side effects, other than perhaps an attack of claustrophobia while in the machine.

Using magnetic fields and radio waves, MRI produces detailed images of the soft tissues and internal organs of the body by creating a temporary magnetic field around the patient’s body. Radio waves are sent and received by a transmitter/receiver in the machine, and these signals are used to produce digital images of the part of the body being scanned.

MRI is used to diagnose and monitor treatment of a wide range of conditions, including tumors, abnormalities of the brain and spinal cord, stroke, and some types of heart problems. A number of people with these conditions are seniors, which is the age range of many pacemaker patients.

Until recently, people with pacemakers could not undergo MRI, which is problematic given that an estimated 75 percent of pacemaker patients will need MRI at some point during the lifetime of the device.

In recent years, new protocols had made it possible for those with pacemakers to undergo MRI, but it was a delicate and risky procedure involving resetting and reprogramming the device before and after the MRI. However, the FDA’s January approval of the Medtronic SureScan Pacing system makes MRI as routine for people with pacemakers as it is for everyone else.

The trouble with pacemakers and MRI has been, of course, the incompatibility of a scan that uses magnetic fields and a device that was made, in part, of metal. Several problems could occur when traditional pacemakers were subject to MRI, explains Raashid Ashraf, MD, of Cardiovascular Associates in Birmingham. The leads that ran from the pacemaker into the heart muscle could overheat, potentially causing tissue damage. Radiofrequency fields could create voltage surges in the leads of the unit causing it to increase stimulation of the heart, potentially causing sustained tachycardia. And the magnetic fields could damage the pacemaker or cause it to shut down. All of these potential glitches are serious enough to make the combination of traditional pacemakers and MRI a very poor idea.

The SureScan Pacing system gets around these problems by a clever design that uses magnetic compatible leads and non-ferrous metals that will not react to the magnetic field. The programming also prevents MRI disasters.

"The system can shut down any leads that begin to heat up or become misplaced," says Ashraf. "MRI is a very important diagnostic tool and its use is growing rapidly. Now people with pacemakers can have MRI when they need it, making it much easier to diagnose and treat the many illnesses, such as degenerative back problems, other musculoskeletal issues, and stroke—problems that are common in older people.”

Medtronic has several pre-screening requirements before patients with SureScan pacemakers are admitted to MRI. Only patients with the complete SureScan system can undergo MRI; the system has to have been implanted for at least six weeks; the pulse generator was implanted in the pectoral region; there are no lead extenders, lead adaptors, or abandoned leads; the leads are electrically intact; and there are no broken or abandoned leads.

Ashraf says that there are no contraindications to the SureScan pacing system. Anyone who is a candidate for other forms of pacemakers will be eligible for the SureScan.

As the population ages, the SureScan should be a great benefit to pacemaker candidates.