Abstract
Background: During atrial fibrillation (AF), ventricular response is highly irregular and thus the beat-to-beat variation of blood pressure is increased because of variations in filling time and in contractility. Objectives: Aim of the present study is to investigate the short-term dynamics of RR and SAP series in patients with AF, during rest and tilt, and after restoration of sinus rhythm. Methods: We computed symbolic sequences of the three phases, as they retain important features of the dynamics generated by the underlying control system. Then we applied a method based on rank order statistics of symbolic sequences to investigate the profile of different types of dynamics. The linguistic distance (range 0-1) between sequences represents a measure of similarity to assess whether the different physiological states are reflected on the dynamics of RR and SAP series. Results: The distance between rest and tilt phases is 0.06 ± 0.02 for RR series, meaning they are very similar, while it is 0.21 ± 0.13 for SAP series, showing a difference in the shortterm dynamics. RR mean decreases during tilt (738 ± 164 vs. 692 ± 152 ms, p <0.05, rest vs. tilt), while mean SAP is not significantly different (101 ± 20 vs. 104 ± 14 mmHg, rest vs. tilt). Comparing AF and sinus rhythm, both RR and SAP series result different in terms of the computed distance. Conclusions: SAP short-term dynamics seem to significantly change when comparing rest and tilt phases, while RR series remain unchanged. Moreover, RR mean but not SAP series significantly decreases during tilt.
Original language | English |
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Pages (from-to) | 516-520 |
Number of pages | 5 |
Journal | Methods of Information in Medicine |
Volume | 49 |
Issue number | 5 |
DOIs | |
Publication status | Published - 2010 |
Keywords
- Atrial fibrillation
- Blood pressure
- Degree of nonrandomness
- Heart rate variability
- Linguistic analysis
ASJC Scopus subject areas
- Health Informatics
- Health Information Management
- Advanced and Specialised Nursing