Research Project
7608733
DESCRIPTION (provided by applicant): The proposed research project will entail the development and initial testing of a novel 3D catheter tracking system for intra-cardiac navigation. The long-term objective of the project is to develop a self-contained tracking mechanism that could be used for any clinical purpose requiring accurate 3D manipulation of catheters inside the heart. The first commercial application currently envisioned would be a system designed to generate 3D maps of the heart's electrical activity and accurately guide the treatment (e.g., radiofrequency ablation) of cardiac arrhythmias. The incidence and prevalence of cardiac arrhythmias has seen explosive growth in the last few decades, mirroring an alarming increase in all forms of heart disease known to trigger and perpetuate rhythm abnormalities. Atrial fibrillation alone has reached epidemic proportions, estimated to currently afflict ~2.3 million Americans and ~5.6 million by 2050. Moreover, the lifetime risk of atrial fibrillation at age 40 is 22-24% and the condition is associated with a two-fold increase in mortality. Traditional treatment modalities, namely drug therapy and open heart surgery, have been found to be inadequate for a growing number of patients, either because of poor efficacy, side effects, or the mere invasiveness of surgical procedures. The advent of specialized percutaneous catheters and the development of other enabling technologies have collectively led to an improvement in the safety and efficacy of minimally-invasive curative procedures. Having grown more than 10-fold in the last decade, catheter-based procedures have become the preferred mode of intervention in symptomatic patients. Cardiac rhythm abnormalities present a major treatment challenge, as they are often selectively triggered and perpetuated by specific areas of the heart that tend to be highly variable between patients. Since most procedures utilize an endocardial approach, effective therapy depends on reliable localization of the aberrant tissue on the complex 3D endocardial surface and the accurate delivery of ablative energy to culprit sites. As the number of catheter-based procedures performed by cardiac electrophysiologists continues to grow, the need for an accurate and reliable catheter tracking system becomes even more apparent. In response to this emerging need, several systems have been developed to facilitate catheter-mediated negotiation of the endocardial surface. Unfortunately, these systems are all plagued by significant limitations, including tracking distortions and inadequate correction for respiration and other motion artifacts. The potential consequences of inaccurate catheter tracking include ablation of electrically normal cardiac tissue, perforation, repeat procedures for recurrence, and increased procedure and x-ray exposure times. Therefore, there is no doubt that more accurate tracking remains a significant unmet need in improving the outcome of percutaneous procedures. The proposed Rhythmia system constitutes next-generation technology that is uniquely architected to provide superior compensation for motion artifacts. Combined with its open platform architecture and accurate real- time correction of field inhomogeneity, the system would address all the shortcomings of existing systems and provide excellent tracking accuracy. By improving the safety profile and long-term success of catheter-based procedures, the Rhythmia system could have a profound impact on the quality of patient care and become the primary 3D tracking tool for ablation procedures as well as additional future cardiac applications. On the heels of previously performed virtual simulations, Phase I of the proposed project will include the development of a working prototype comprising of a tracking catheter, relevant hardware (amplifiers and filters), and a workstation running a visualization module and proprietary algorithms. Once operational, the system would be tested and improved using bench-top phantom models mimicking the electrical properties of blood and structures surrounding the heart. Specifically, Phase I will have the following aims: (1) Develop a prototype system that would be able to track the 3D location of multiple electrodes within an ex-vivo test chamber. (2) Quantify tracking accuracy ex vivo when electrode-bearing catheters are immersed and surrounded by a medium of homogeneous conductivity. (3) Quantify tracking accuracy ex vivo when catheters are immersed in an inhomogeneous medium, reference electrodes are employed, and motion is introduced. Feasibility will have been demonstrated when at the end of Specific Aim #3, the system can demonstrate sub- 2mm error in measuring the distance between 2 tracked electrodes (known to be 20mm apart) located within 50mm of the tracking catheter. Upon successful completion of bench-top validation, Phase II would be commenced comprising of large animal studies. PUBLIC HEALTH RELEVANCE: Cardiac rhythm abnormalities afflict a growing number of patients, with estimates ranging from 6 to 10 million people in the US alone. Minimally invasive procedures, such as catheter ablation, are quickly emerging as the preferred approach to eliminate cardiac arrhythmias and restore normal heart beat. The proposed project looks to develop next-generation technology for more accurately localizing catheters in 3D space as they are roving within the heart chambers in order to improve both the safety and effectiveness of therapeutic procedures.
