Heart disease is by far the No. 1 killer in the United States, claiming more lives than all forms of cancer combined. Fortunately, diagnosing this disease has become much easier in recent years, thanks to new technology and a better understanding of the risk factors. What doctors have always wanted, however, was a way to predict which of their patients might be at risk for an imminent heart attack.
That’s exactly what a team from Wake Forest University Baptist Medical Center thinks it has found, using something called a cardiac MRI. It’s the same type of MRI machine used to scan the brain or spine, but customized with special software that allows it to take real-time pictures of the beating heart. Dr. Gregory Hundley and his colleagues studied almost 300 patients and in their recent report published in the journal Circulation, found that it was possible to predict from those images which of their patients already suffering from heart disease were potentially at risk for an attack.
This is how the exam works. A patient is put on an MRI table and the machine takes pictures of the heart then transmits them to a computer. Doctors can monitor all four heart chambers on a monitor in real time, then save the information for review later. Once the pictures have been taken while a patient is at rest, the medications dobutamine or atropine are administered. They make the heart beat stronger and faster, and another set of pictures is taken. Doctors can then compare the at-rest pictures and those with the heart “under stress.”
You have probably heard of the traditional stress testing, when patients will walk on a treadmill for a certain period of time at different speeds while an EKG records the heart’s electrical activity. This has been a standard in exercise-stress testing, with physicians collecting important information about how the heart responds under stressful conditions such as shoveling snow or climbing stairs.
The cardiac MRI, however, has several advantages over the older tests. First, not everyone is able to undergo traditional stress testing, often because they are too sick to tolerate the physical exertion. Second, by examining clear, real-time pictures of the beating heart, doctors can evaluate how well or how poorly the heart walls contract. These pictures even allow physicians to identify potential trouble areas, such as part of the heart muscle that’s not moving properly to pump the blood. The test are also noninvasive and fast. Most are done in less than an hour and the results are immediate.
Richard Lowder of Winston-Salem, N.C., is a longtime heart-disease sufferer who had undergone angioplasty in the past to clear his blocked coronary arteries. He had a cardiac MRI scan two years ago and insists that it saved his life. “If I didn’t have the test when I did, I wouldn’t be here right now. My doctors took one look at the results and said I needed surgery immediately.” Lowder first underwent the treadmill-exercise stress test, but the results were inconclusive, so his doctors ordered a cardiac MRI. The images showed that his heart muscles weren’t contracting equally, raising concern about an imminent heart attack. Lowder’s doctors performed a successful triple bypass.
At $450, the cost of a cardiac MRI is relatively inexpensive. And most insurance companies cover the procedure if it’s ordered by a physician and the scan can be saved by the computer and viewed at a later date if it needs to be compared to another study. Experts predict that as more physicians make use of the cardiac MRI and as manufacturers continue to make technical improvements, the machine, along with CT scans, can save those patients at most risk from permanent damage.
