Dr. Coman is an Associate Professor of Medicine at the University of Oklahoma College of Medicine, as well as a practicing electrophysiologist with the Oklahoma Heart Institute where he specializes in cardiac electrophysiology, ablation therapy and pacemakers. In addition to being a highly credentialed cardiologist, Dr. Coman has a degree from Vanderbilt in biomedical engineering. He currently serves as the Director of Electrophysiology at Hillcrest Medical Center, and is board certified in Internal Medicine, Cardiovascular Disease, and Cardiac Electrophysiology. Dr. Coman has several fellowships and research articles to his credit, but some of his greatest successes have been educational initiatives and public awareness campaigns.
Body1: Dr. Coman, you’ve said that you’re most proud of your work towards improving ICD implantation rates in the United States. For our readers, an implantable cardioverter defibrillator (ICD), also known as a "defibrillating pacemaker," is a device implanted in the patient’s chest to correct an irregular heartbeat. What can you tell us about the evolution of this device?
Dr. Coman: Originally, implantation devices were almost as large as a VHS cassette tape; and there was risk associated with putting in such a large device. The development of a wire, or a "lead," was able to make the procedure much safer. The risk of the procedure plummeted to almost zero. Now these devices are about the size of a pacemaker, and can be put under the collarbone. The risk is fractional.
Defibrillators are now a very mature technology. The implantation times are low, the complication rates are low, the devices are lasting about eight years; we hardly see a failure nowadays. Most of the changes coming about are changes in the populations who need them. In the future, I hope to see improvements in our ability to predict who is about to have a cardiac arrest.
Cardiac arrest, or sudden death, is the number one killer in the United States: it kills more people than strokes by almost a two-to-one margin. My current focus in patient care is reduction in sudden death rates by the identification of high-risk patients. Fortunately, we have tools now available to us that will allow us to predict which patients are likely to suffer from sudden death. The number one predictor for cardiac arrest is the ejection fraction.
Body1: Tell us more about the significance of the ejection fraction.
Dr Coman: The ejection fraction is a number which represents the amount of blood squeezed out every time the heart beats. A normal number is about 60% The lower a person’s ejection fraction, the greater his or her risk. When the number gets to 40% or lower, we begin to get concerned.
We’ve done a great job around the country with educating people about cholesterol. Accordingly,
our goal would be to make knowing your ejection fraction as common as knowing your cholesterol count. It’s a simple number, and it’s not too hard to understand what it is. More widespread knowledge of the ejection fraction will allow the topic of sudden death risk to be more freely discussed. If we can educate physicians around the country that sudden death is far and away the number one killer in the United States--and we already have the cure--then we would have a much greater utilization of ICDs. And by doing that, we could easily save a huge portion of the number of people dying.
Body1: Given the seriousness of this public health problem, how do you explain the lack of public awareness?
Dr. Coman: I think the problem is the lack of a survivor constituency. The disease is not a symptomatic process; it’s not stretched out over months, weeks, or even days. Because 97% of people who have their first episode die from it immediately, we really don’t have a constituency. As a disease, cardiac arrest is rapid, it is silent, and it is deadly; and because it is so rapid, it is frequently misconstrued. For example, when a high-profile patient suffers from sudden death, the newspaper usually reads, "Massive Heart Attack." This is a complete misconstruction.
Body1: What kinds of educational campaigns have you worked on?
Dr. Coman: Several initiatives I’ve been involved with have taken place at both the local and national level. Last year, in the Tulsa area, we had two high school students die of sudden death. That was a tragic event; but out of that event, some good can come. In that instance, we joined with both national foundations and local corporations to provide automated external defibrillators to every high school in the area.
Body1: Who have been your greatest partners in these educational campaigns?
Dr. Coman: They have been mostly other physicians, and the companies who develop these devices. These companies have a vested interest in serving those patients well. The device companies have done an outstanding job at pushing for public education. Our national organizations are also beginning public education campaigns to help with this problem.
Body1: Dr. Coman, your clinic also has the largest body of experience in the world with pacemaker/MRI or ICD/MRI interactions. Currently there are risks associated with patients who have ICDs receiving an MRI, so much so that the FDA has contraindicated MRIs for people with pacing devices. Can you tell us more about this?
Dr. Coman: There are numerous theoretical problems that could occur by placing those pacing devices in this intense magnetic field. The problem is that the FDA contraindication is based on theory. Around the world, 250 pacemakers patients have had MRIs. Of those patients, none of them have had any significant complication as a result of the scan.
There’s a lot of voodoo around this. There are about four things that can happen when you put a pacing in an MRI field. It also turns out that reprogramming the device would relieve essentially none of these complications. At Oklahoma Heart, several years ago, we developed a protocol to study this interaction. We took any patient who needed an MRI for any reason, and if they had a permanent indwelling pacemaking device, as long as they were not dependent on the device for pacing, we put them in the field with no reprogramming. It turns out that very few patients are truly dependent on their device. (By "dependent," we mean they truly have a heart rate of zero without the device.)
We’ve had just over seventy patients who’ve had this done, and we’ve seen no clinical complications. We hope we can adjust that FDA statement to become a cautionary statement, stating that as long as appropriate precautions are taken, this combination of procedures is much safer than anyone would have thought.
We’re in the process of reporting our findings to a major journal for publication, and
the Mayo clinic is now investigating this issue in a fashion similar to ours. I suspect that in a couple of years, our data will be widely recognized. Once you get a foothold for something like that, it really does spread like wildfire. Given the number of patients who are currently receiving defibrillators, which is currently becoming very large, and the number of patients needing MRI, which is a rapidly expanding diagnostic tool, obviously the two procedures will continue to intersect.
Body1: Dr. Coman, you’ve pinpointed CRT, or cardiac resynchronization therapy, as one of the most important new trends in cardiac treatments. Cardiac resynchronization therapy is a promising new use of heart pacing technology. (For our readers, more information and an animation of the procedure can be found at http://www.medtronic.com/hf/device.html.) Why is this new technology so exciting?
Dr. Coman: Cardiac resunchronization therapy gives us the ability to use pacing technology in a completely different environment. In the past, this technology was only used to speed up a heart rate that was too slow. Now, we can use it to address cardiomyopathy, in which the weakened heart muscles suffer from a slowing of the electrical impulses around the heart. With CRT, we can eliminate that slowing of electricity. This changes the quality of life for patients who have cardiomyopathy. These patients are often symptomatic every moment of their lives; and, because there just aren’t enough hearts to go around, transplants are not always possible. So, here, we have a chance to use pacing technology to complete change the way we treat congestive heart failure in the U.S.
People with cardiomyopathy who receive CRT feel better; they’re less short of breath. And there are millions of people suffering from cardiomyopathy in the U.S. These people are symptomatic, and the disease is prolonged, so they’re eagerly looking for treatment. They’re going to their doctors every day and saying, "Isn’t there something you can do for me?"
The beauty is, this is the same group that is at high risk for sudden death. So, we can marry a defibrillator, which could prolong their life, with a technology like CRT, which improves their quality of life. This, frankly, is very uncommon in medicine: If you look at all therapies, in all fields of medicine, you see that it’s unusual to be able to improve patients’ length of life and quality of life at the same time, which is one reason I am fortunate to be in this field. This technology has come into full clinical form really only in the past year, and CRT is not yet as mature a therapy as the defibrillators are. In the field of electrophysiology, I think the next five years are going to be just exciting as the last five years have been.