| Image-based Management of Atrial Fibrillation |
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Collaborating Investigators: Nassir Marrouche MD, Chris McGann MD The CIBC Center continues to work in close collaboration with Dr. Nassir Marrouche and his team at the Comprehensive Arrhythmia Research and MAnagement (CARMA) Center to advance the state of technology used for the monitoring and treatment of Atrial Fibrillation (AF). AF is an electrophysiological rhythm disorder that causes the upper chambers of the heart to beat in an desynchronized, chaotic fashion that results in reduced pumping efficiency in the heart. This condition represents the most frequent type of cardiac rhythm disorder, one that significantly increases the risk of stroke, increases the chance of death, and diminishes quality of life. This problem already affects some 4 million Americans and the incidence is increasing within the aging populations of the world.
Magnetic resonance imaging (MRI) visualization has the potential to reveal important data about the condition of cardiac tissues, such as the presence and location of fibrosis in the left atrium pre-ablation or the distribution of post-ablation scar formation.1,2,3 This information could be critical in planning the application of ablation therapy and guiding the ablation process. Using MRI during ablation would allow physicians to see the extent of ablation lesions as they form and provide a possible means of guiding the placement, energy level, and duration of each ablation to achieve optimal results. Before MRI can be used for these purposes, a number of challenging technical problems must be solved.4 A successful solution would require high-resolution MRI and a way to compensate for the distorting effects of movement from respiration and cardiac motion. Image processing of the MRI must be optimized and automated to provide rapid results and help guide the ablation procedure. Dr. Marrouche and his team at the CARMA Center have made encouraging progress in overcoming these hurdles. The CIBC software development team works closely with Dr. Marrouche and the CARMA team to develop segmentation software and SCIRun based tools for the evaluation of MRI images that are optimally suited to the needs of the CARMA researchers. Ongoing multicenter trials with other AF treatment centers around the world seek to validate the advances achieved by the CARMA group and CIBC with the shared goal of improving the management of this disease through non-invasive imaging. [1] A. Kolandaivelu, A.C. Lardo, and H.R. Halperin. Cardiovascular magnetic resonance guided electrophysiology [2] T.J. Badger, Y.A. Adjei-Poku, and N.F. Marrouche. Mri in cardiac electrophysiology: the emerging role of [3] N. Akoum and N.F. Marrouche. Real-time imaging in electrophysiology: from intra-cardiac echo to realtime [4] A. Pandit and N.F. Marrouche. Cardiac magnetic resonance in the world of the cardiac electrophysiologist: |
The only truly curative treatment for AF is a procedure known as ablation. In ablation, a catheter is inserted through the veins into the heart and some form of energy is applied to the inner surface of the heart (the endocardium) to electrically isolate the pulmonary veins. These pulmonary veins flow from the lungs into the left atrium and are considered the dominant site of the stimulus for AF so that electrically isolating them by means of tissue burns reduces or eliminates the stimulus for AF. Ablation is gaining popularity because, unlike pharmachological treatments, it represents a true cure that carries virtually no side effects. However, the treatment has not been successful for all patients for reasons that are not fully understood, but may be associated with pre-existing fibrosis in the left atrium. MRI provides a means to observe and evaluate this fibrosis and, with measurements of the extent of fibrosis, a means of predicting outcome and a basis for treatment guidance.
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