EPs speak about implanting first MRI-compatible pacemaker

Ilana Kutinsky, DO, implanting the first MRI-compatible pacemaker.

Earlier this month, the FDA approved the first MRI-compatible pacemaker (Medtronic). In an exclusive interview, Thomas Mattioni, MD, director of electrophysiology at Scottsdale Healthcare in Scottsdale, Ariz., and Ilana Kutinsky, DO, an electrophysiologist at Beaumont Hospitals in Royal Oak, Mich., who implanted the first devices at their facilities, said the 10-year wait for the device was worth it.

In a 2007 scientific statement, the American Heart Association (AHA) noted that under certain circumstances it is safe to use MRI in these patients. Why is there a need for a specific MRI-compatible pacemaker? 

Kutinsky: There are case reports showing ways to shield old devices to perform an MRI exam on a part of the body that is relatively far from the device, such as the ankle. But this type of exam cannot be performed in routine MRI settings and the FDA has to be intimately involved with the process. The FDA does not approve MRI scans with current non-MRI compatible devices. I have tried in the past to schedule orthopedic scans for patients with implants to no avail, even though theoretically it should be fine.

Mattioni: The AHA guidelines are not for routine MRI exams. They are for certain circumstances when the clinician feels the information derived from MRI would be so valuable that he or she would be willing to take a small risk. It is my experience, however, that most imaging centers and hospitals will not perform MRI exams on patients with implantable devices. It is unclear whether that decision is financially motivated, as the CMS [Centers for Medicare & Medicaid Services] will not reimburse for an MRI scan in any patient with an implanted cardiac rhythm device or one of safety. But the marketplace certainly needed a device specifically designed and tested to make it safe for MRI scanning.

Are there contraindications for the Revo MRI SureScan pacemaker or special precautions imagers must take?

Mattioni: The exam must be performed on a 1.5T scanner, as the device was not tested on 3T machines. Also, even though the leads and pulse generator were specifically designed for the MRI environment, the device must be programmed into the MRI safe mode prior to the scan, which allows it to pace and recognize it is in the MRI environment. After the scan, the device needs to be unprogrammed out of MRI safe mode. This can be achieved by a physician, technologist or company representative. The next-generation device, which is not approved in the U.S., detects when it is in an MRI environment and goes into the safe mode automatically.

Do you intend to implant only this MRI-compatible pacemaker now or is there a specific patient selection process you will consider?

Kutinsky: We will consider each patient case individually as the device at our hospital costs about 25 percent more than a conventional pacemaker. If we feel the patients will have to undergo MRI tests in the future, we will strongly consider this new device. These could be younger patients who may need to have their joints imaged by MRI, patients with heart disease or certain patients with cancer. The 87-year-old patient in whom I implanted this new device at Beaumont had a meningioma and had been undergoing MRI scans every few years.

Mattioni: At this stage, we are trying to selectively use it in patients likely to require an MRI exam. These could include patients with many comorbidities, neurologic conditions such as multiple sclerosis or dementia, any kind of central nervous system disease that would require regular imaging, and those with joint problems such as arthritis. The 81-year-old patient who received the first device at Scottsdale had central nervous system disease.

It's estimated that 75 percent of patients with pacemakers will require an MRI scan at some point during the life of the device, which is about eight years. The industry as a whole is moving in the direction to develop all cardiac rhythm devices for use in an MRI scanner.

Are there any characteristics about the device that make it different—harder or easier—than other devices to implant?

Kutinsky: It's fairly similar. The leads are thicker, 7.5 Fr, whereas the typical lead is 7 Fr.

Mattioni: The mechanism for the lead screw technique is different. You have to use a few more turns and watch the extension of the screws under fluoroscopy to see how they are coming out, because the torque isn't being transmitted to the tip on a one-to-one ratio.

What are the problems patients with non-MRI compatible pacemakers could have in an MRI scanner?

Kutinsky: There are two parts to the pacemaker, the pulse generator and the leads. The generator can be reset from the magnetic field and if someone is pacemaker-dependent, such a resetting could be fatal. Regarding the leads and the screws, they can heat up and burn tissue, potentially causing a fatal arrhythmia, or the leads could dislodge. There are some data suggesting the batteries can get drained from the magnetic field.

How common is it for patients with pacemakers to undergo MRI imaging and what are the common indications for these exams?

Kutinsky: We are using MRI for many more indications than we did just a few years ago. For example, five years ago, it was not routine to get a cardiac MRI, but now we use it frequently in our EP patient population. I have patients with cardiac disease that can only be evaluated on MRI. When these patients receive implantable devices, they are essentially cut off from this valuable test. We have been waiting 10 years for this first MRI-compatible device and it's only a matter of time before defibrillators and resynchronization devices become MRI-safe as well.

Since this device is FDA approved for MRI use, are payors reimbursing for the imaging test?

Mattioni: My understanding is that Medtronic has started the process to get MRI scanning approved for reimbursement.