For many pacemaker people, these things are easily avoided. But many people need regular MRI scans to monitor ongoing conditions, such as cancer. Besides that, people really cannot predict if they might suddenly be put in a situation where an MRI scan is prudent if not crucial. But if you have a pacemaker, that's a no-no.

An MRI is a special imaging technique that helps doctors get a visual picture of soft tissues, including organs and possibly tumors. Many MRIs are like giant tubes; the patient is placed on a gurney and then pushed inside the MRI. The MRI machine takes a sequence of images which are then assembled together by the device's software to create the scans. During the sequence of images, the MRI may make a noisy pounding noise. An MRI can take many minutes to produce. In recent years, the claustrophobia-inducing tube-type MRI machine has been replaced by so-called "open MRI" machines and even standing MRIs (that's where you stand up throughout the scan).

The problem with MRIs and pacemakers is inherent in the "M" in MRI. MRIs use powerful magnets to create their images. Magnets can mess with the pacemaker's internal workings. In fact, one way to "reset" a pacemaker and cause it to "safety pace" (pace without sensing) is to put a magnet directly over it. Furthermore, the pacemaker is made out of metal and the magnetic force of the MRI machine can pull on the pacemaker as attracts it.

But an even bigger issue is that the MRI machine can start to heat up the pacemaker and the lead. If the pacemaker and lead(s) get too hot, they burn delicate cardiac tissue. An MRI can be potentially life threatening to a pacemaker person!

Right now, most pacemaker people who need some kind of scan of soft tissue can opt for a CT-scan (or "CAT" scan) which is generally considered safe for pacemaker patients. However, there are times when an MRI is better for what the doctor needs to see. In 2007, a total of 26 million MRIs were conducted in the U.S.; it's a familiar and reliable and frequent type of medical imaging.

Medtronic, the world's largest pacemaker manufacturer, has a new pacemaker on the way to approval. It's called EnRhythm MRI SureScan. The pacemaker was explicitly designed to be MRI-safe. It is rumored–but we cannot confirm it–that other manufacturers are working on similar producs.

Right now, EnRhythm MRI SureScan is not commercially available. It is currently under consideration by the FDA.

So how did a woman from the little town of Wimberley, Texas, get the first one ever to be implanted? The 45-year-old woman found out she needed a pacemaker after suffering some fainting spells. The problem was that she had Cushing's disease, which was caused by a couple of tumors on or around her pituitary gland. The woman needed to get an MRI every six months to monitor the condition which is associated with fatigue, weakened bones, and muscle weakness.

Her conundrum was that the pacemaker she needed would make it impossible to monitor her Cushing's disease. She visited a hospital in Austin and talked to a cardiologist there who knew about the MRI-safe pacemaker in development. The cardiologist got in contact with the Medtronic's representative who worked with officials at the company and the FDA to get special permission to use the new pacemaker before it is officially approved. This kind of special dispensation is known in the business as "compassionate use."

Compassionate use of a device allows the FDA to waive restrictions and will let the woman get a pacemaker that is not yet commercially on the market. To get a compassionate use waiver, one has to work with both the manufacturer and the FDA (not to mention the doctor) and complete a great deal of paperwork.

Fortunately for the woman from Wimberley, Texas, it was completed relatively quickly and she was able to get her MRI-safe pacemaker and also make some news as the first woman to get the MRI-safe pacemaker.

Although it is always a little bit tricky to "predict" when products will be approved by the FDA, it is anticipated that the MRI-safe pacemaker will be cleared for market release in the spring of 2010.

When a new pacemaker is evaluated by the FDA, the manufacturer is asked to submit what is loosely called "data," but that makes it seem like it's no big deal. Data come from a variety of sources, including all kinds of clinical and bench testing. Manufacturers are expected to conduct and fund these tests which the FDA monitors. The results of all of these studies (the "data") are then reviewed by the FDA and play a major role in whether or not the device is approved so that it can be sold in the U.S.

The FDA approval process (technically called "clearance" since the FDA really does not "approve" or put a stamp of approval on anything; it clears for market release) is important. The U.S. Supreme Court has found that if the FDA approves a pacemaker or other medical device for sale, manufacturers are somewhat protected in the event that patients sue the manufacturer over the device.

Two studies were recently released (just this week) that indicate the FDA is likely going to be increasing scrutiny on medical devices like pacemakers and stents. One study was conducted by the FDA itself in conjunction with Beth Israel Deaconess Medical Center in Boston. That study found that in the clinical trials submitted to the FDA for use in product approvals from the time 2000 to 2007, about 40% of the studies used for cardiac devices lacked "high-quality data" about the treatment or safety goals of the study.

Nobody so far has made any connection that lack of high-quality data has led to substandard devices being approved. However, the first study by the FDA itself showed that data it accepted was not sufficient.

A second study was conducted by researched at the University of California San Francisco was just published in the prestigious Journal of the American Medical Assoociation. Dr. Rita Redberg was one of the investigators and she was quoted in the New York Times as saying that many cardiac device trial lacked sufficient "scientific rigor." This study was more critical of the FDA but has come under fire itself.

One of the problems with the California study, according to the New York Times article, was that authors tried to make standards in drug testing applicable to testing pacemakers and other devices and clinical trials for devices have be conducted differently for many reasons.

While experts continue to wrangle out the issues, this definitely means that the approval process for pacemakers and defibrillators will be scrutinized even more intensively in 2010 and beyond. Chances are very good that some of the procedures in place right now will be changed. In fact, the FDA already started to review its device approval procedures back in 2007 and that will continue in the wake of these two studies.

Fallout from these studies will go beyond pacemakers to include other "medical devices," like implantable hips and knees, spinal implants, and implantable pumps.

What does all this mean? For patients, it means that future pacemakers may be subject to more scientifically sound study. That's good news. For manufacturers, it may mean more expensive studies or some lost time as the confusion gets sorted out. The best possible outcome of this finding is that the medical community will join forces with the FDA to achieve practical, workable, but scientifically sound ways to evaluate new pacemakers and other medical devices.