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Imaging meets Electrophysiology to Help People with Heart Troubles

afibA group of scientists and physicians at the University of Utah is addressing the growing problem of AF through a combination of high tech interventional therapy, multimodal medical imaging, image processing and analysis, and computer science.

Atrial fibrillation (AF) is the most common—and perhaps most insidious—form of heart rhythm disturbance. In AF, the upper two chambers (the left and right atria) of the heart lose their synchronization and beat erratically and inefficiently, reducing the pumping capacity of the heart and elevating the heart rate, eventually leading to a stroke. The same condition in the lower chambers (ventricles) of the heart is fatal within minutes and defibrillators are necessary to restore coordination. In the atria, death is stealthy and occurs over years.

A group of scientists and physicians at the University of Utah is addressing the growing problem of AF through a combination of high tech interventional therapy, multimodal medical imaging, image processing and analysis, and computer science. The treatment known as “atrial ablation” requires that large areas of the posterior wall of the left atrium be rendered electrically inactive. This part of the heart is the origin of the fibrillation and by suppressing its electrical activity, the heart can return to—and, more importantly, stay in—normal rhythm. To carry out ablation, the physician, under image guidance, places a catheter in the left atrium and uses it to apply radiofrequency energy to heat a series of small spots on the atrial wall.Medical imaging is at the “heart” of this project as it plays a role at all stages. The imaging specialists Drs. Parker, DiBella, and Kholmovski, all from the Utah Center of Advanced Imaging Research (UCAIR), have developed new ways of using magnetic resonance imaging (MRI) to visualize the walls of the atria, which are only a few millimeters in thickness, a task previously considered almost impossible in a beating heart. The cardiology team, Drs. Marrouche and McGann, then recognized that the MRI images of the atrial walls of some patients looked different from others and set the image processing team, Dr. MacLeod and specialists at the Scientific Computing and Imaging (SCI) Institute, the task of visualizing and quantifying these differences.

The results were striking and allowed the team to create a method that appears to identify and measure regions of the heart that are most altered by the AF. The resulting index can serve to differentiate between good and bad candidates for treatment. This discovery represents a potential breakthrough in treatment as there is no other way to determine suitability of patients before the procedure.

The team aims to transform the integration of imaging modalities and especially the role of MRI during the ablation procedures. MRI is the only modality capable of seeing the effects of ablation and thus has the potential to monitor the formation of the lesions that suppress unwanted electrical activity. MRI can also provide images of the lesions as they progress from acute injury to stable scars and thus offers the only noninvasive means to follow patient progress during the procedure and in the following weeks and months.

The project has so far captured a great deal of attention from industry and most of the financial support for the experiments and research comes from companies like Siemens Medical, Surgivision, and Biosense Webster (Johnson & Johnson). The University of Utah, School of Medicine has also thrown its support behind the project through its commitment to construct the integrated clinical suite that will support both research and clinical application of the results of this project. Public funding from the NIH takes longer to mobilize and multiple grant applications are in all stages of development and evaluation. The hope of the group is to create effective private/public partnership that will allow for rapid translation of ideas from the lab to the treatment of patients.