Applying non-linear dynamics to atrial appendage flow data to understand and characterize atrial arrhythmia
- Cleveland Clinic Foundation, Cleveland, Ohio 44195 (United States)
- Naval Undersea Warfare Center, New London, Connecticut 06320 (United States)
The aim of this study was to better understand and characterize left atrial appendage flow in atrial fibrillation. Atrial fibrillation and flutter are the most common cardiac arrhythmias affecting 15% of the older population. The pulsed Doppler velocity profile data was recorded from the left atrial appendage of patients using transesophageal echocardiography. The data was analyzed using Fourier analysis and nonlinear dynamical tools. Fourier analysis showed that appendage mechanical frequency ({ital f{sub f}}) for patients in sinus rhythm was always lower (around1 Hz) than that in atrial fibrillation (5-8 Hz). Among patients with atrial fibrillation spectral power below {ital f{sub f}} was significantly different suggesting variability within this group of patients. Results that suggested the presence of nonlinear dynamics were: a) the existence of two arbitrary peak frequencies {ital f{sub 1}, f{sub 2}}, and other peak frequencies as linear combinations thereof ({ital mf{sub 1}{+-}nf{sub 2}}), and b) the similarity between the spectrum of patient data and that obtained using the Lorenz equation. Nonlinear analysis tools, including Phase plots and differential radial plots, were also generated from the velocity data using a delay of 10. In the phase plots, some patients displayed a torus-like structure, while others had a more random-like pattern. In the differential radial plots, the first set of patients (with torus-like phase plots) showed fewer values crossing an arbitrary threshold of 10 than did the second set (8 vs. 27 in one typical example). The outcome of cardioversion was different for these two set of patients. Fourier analysis helped to: differentiate between sinus rhythm and atrial fibrillation, understand the characteristics of the wide range of atrial fibrillation patients, and provide hints that atrial fibrillation could be a nonlinear process. Nonlinear dynamical tools helped to further characterize and sub-classify atrial fibrillation.
- OSTI ID:
- 401706
- Report Number(s):
- CONF-950730-; ISSN 0094-243X; TRN: 96:029491
- Journal Information:
- AIP Conference Proceedings, Vol. 375, Issue 1; Conference: 3. technical conference on nonlinear dynamics (chaos) and full spectrum processing, Mystic, CT (United States), 10-13 Jul 1995; Other Information: PBD: Jun 1996
- Country of Publication:
- United States
- Language:
- English
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