| dc.contributor.author | Penney, Cindy Jane. | en_US |
| dc.date.accessioned | 2014-10-21T12:33:53Z | |
| dc.date.available | 1999 | |
| dc.date.issued | 1999 | en_US |
| dc.identifier.other | AAINQ49284 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55666 | |
| dc.description | Electrocardiograms (ECGs) recorded from the body surface reflect electrical activity of the heart. When a coronary artery is occluded, as occurs in balloon-inflation coronary angioplasty, blood flow is suspended, cellular oxygen supplies are depleted, and ischemia develops, altering cardiac electrical activity. The aim of this study is to locate ischemic regions of the heart by computing an image of the potentials on the heart surface from the body-surface ECGs. Rigorous mathematical methods are developed, which introduce regional constraints to overcome the ill-posed nature of this problem. | en_US |
| dc.description | Applying analytical techniques to increase the accuracy of the discretized torsoheart system improved a first estimate of the epicardial-potential distribution, as tested by simulated potential distributions. The composite regional constraint---with spatial smoothing of low-amplitude potentials, removal of spurious extrema, and temporal smoothing---was developed and applied, further refining the solution. Calculating the regularization parameter with the newly introduced Slope Estimation Method resulted in near-optimal solution for simulated potential data. This inverse solution was successful in localizing the ischemic zone to a region perfused by the occluded artery, and showed very good spatial agreement with localization by radionuclide myocardial-perfusion imaging. During balloon inflation, epicardial electrograms from the ischemic zone had ST-segment and QRS-complex changes indicative of ischemia Overall, the results suggest that the technique of calculating epicardial potentials from multiple ECGs recorded on the body surface holds great promise as a noninvasive imaging modality. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1999. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Engineering, Biomedical. | en_US |
| dc.subject | Health Sciences, Medicine and Surgery. | en_US |
| dc.subject | Biophysics, Medical. | en_US |
| dc.title | Noninvasive imaging of epicardial potentials: Regional constraints and clinical applications. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
