Date of Award
2026
Document Type
Open Access Master's Thesis
Degree Name
Master of Science in Biomedical Engineering (MS)
Administrative Home Department
Department of Biomedical Engineering
Advisor 1
Hoda Hatoum
Committee Member 1
Sean Kirkpatrick
Committee Member 2
Jingfeng Jiang
Abstract
Purpose: Atrial fibrillation (AF) increases thromboembolic risk, yet the isolated hemodynamic contributions of atrial contraction loss, cardiac output (CO) reduction, and patient-specific atrial geometry remain incompletely understood. This study aimed to disentangle these factors and quantify their independent effects on left atrial (LA) flow and stasis. Methods: Five patient-specific left atrial geometries were evaluated using CFD. For each geometry, the sinus rhythm transmitral waveform was used as the baseline and modified to represent AF with compromised and conserved CO. Hemodynamic endpoints included LA velocity, time-averaged wall shear stress (TAWSS), relative residence time (RRT), oscillatory shear index (OSI), atrial wall shear stress divergence (AWSS), and threshold-defined blood stasis metrics. Results: AF-compromised CO conditions resulted in decreased LA velocity, decreased TAWSS (0.788 Pa to 0.508 Pa), increased RRT, and increased blood stasis regions as defined by velocity (61.8%), TAWSS (86.7%), and RRT (88.5%). When CO was conserved under AF conditions, peak velocity magnitude and TAWSS were partially restored (0.508 Pa to 0.827 Pa), with reductions in RRT and stasis ratio (velocity: 42.5%; TAWSS: 59.8%; RRT: 71.7%); however, cycle-integrated flow characteristics remained altered relative to sinus rhythm. The loss of atrial contraction reduced near-wall stirring as outlined by the divergence of AWSS. Conclusion: AF promotes hemodynamic conditions associated with increased blood flow stasis through the combined effect of atrial mechanical loss, reduced CO, and patient-specific anatomy. Restoration of CO alone does not fully normalize atrial flow organization, which highlights the independent contribution of the A-wave to LA washout and near-wall transport.
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Recommended Citation
LaBonte, Hailey, "DISENTANGLING THE HEMODYNAMIC EFFECTS OF ATRIAL CONTRACTION LOSS AND CARDIAC OUTPUT REDUCTION IN ATRIAL FIBRILLATION", Open Access Master's Thesis, Michigan Technological University, 2026.
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Biomechanics and Biotransport Commons, Cardiology Commons, Other Biomedical Engineering and Bioengineering Commons