Date of Award
2007
Degree Type
Thesis
Degree Name
Master of Engineering Science
Program
Biomedical Engineering
Supervisor
Dr. Terry M. Peters
Abstract
Electrophysiological cardiac data mapping, the recording and analysis of the electrical activation patterns of the heart, can be used to study cardiac rhythm disorders, such as atrial fibrillation. Over the past decade, various advanced cardiac mapping systems have been developed to create detailed cardiac maps and assist physicians in planning and delivering therapy. While these systems have increased the ability to study and treat cardiac arrhythmias, inherent limitations exist. The work presented in this thesis describes a system that creates dynamic cardiac maps, using patient-specific cardiac models. This thesis details novel approaches to collecting dynamic electrophysiological cardiac data, registering the data with patient specific cardiac models, and displaying the data directly on the model surface, giving a more accurate and comprehensive visualization environment compared with current technology. The dynamic cardiac mapping system uses magnetically tracked electrode catheters to associate spatial locations with cardiac electrograms collected over the entire car diac cycle. Two novel 4D shape registration algorithms are introduced, which extend upon existing 3D approaches, to permit a more accurate and robust alignment of the image-space and real-space environments. Once the data have been collected and aligned with the pre-operative imaging environment, they can be interpolated across a patient-specific cardiac surface model. Additionally, the dynamic nature of the system allows for frequency domain analysis of the collected signals. To validate the system, a series of laboratory and in-vivo experiments were conducted. For the registration algorithms, clinical cardiac mapping data was simulated by adding random noise and applying various transforms to sampled locations of the cardiac surface model. The algorithms were used to find an inverse transformation to correctly align the data and model, and the results were compared to a traditional 3D shape registration method. The dynamic cardiac mapping system was evaluated in series of laboratory studies that were conducted to test a user’s ability to accurately locate a landmark in physical iii space, and the accuracy to navigate to a virtual location. Finally, the overall system performance was compared to an existing electrophysiological recording system in an in-vivo porcine experiment, where right atrial cardiac maps were created during sinus and paced cardiac rhythms. Experimental results showed that the 4D shape registration methods yield more accurate transformations in comparison to the traditional 3D approach (4D errors: Translation 0.4mm, Rotation 0.4° vs. 3D errors: Translation 1.3mm, Rotation 1.9°), while increasing the success rate and capture range of the algorithm. For the dynamic mapping system, the RMS physical accuracy and virtual accuracy were 3.9mm and 3.7mm respectively, similar to those values measured in a static mapping environ ment. Finally, in the in-vivo experiment, the dynamic cardiac mapping system was validated against a commercial electrophyiological recording system, and was able to create a dynamic cardiac map displayed on a cardiac surface mode
Recommended Citation
Wilson, Kevin, "Dynamic Electrophysiological Cardiac Mapping with Patient-Specific Cardiac Models" (2007). Digitized Theses. 5074.
https://ir.lib.uwo.ca/digitizedtheses/5074