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A symbolic analysis of heart rhythm fragmentation

Elwira Schneider

Abstract

The aim of this thesis is evaluation of the effectiveness the symbolic method to analyze the degree of heart rate fragmentation for healthy people and people affliected by aortic stenosis. Data used for the researches belonged to healthy people and patients with aortic stenosis. The healthy group consisted of 34 people, and the group of patients consisted of two subgroups of 16 people each. The separation criterion was the patient's death within 30 days of the valve replacement surgery. Patients who died in the postoperative period belonged to the research group, and the control group were people who did not die at that time. Individuals from the research group and control group were paired in terms of gender, age, comorbidities and BMI. The heart rhythm records belonging to the patients had annotation of the data, while those belonging to healthy people who did not have it. Therefore, the signals of the aortic stenosis patients were analyzed with omission and without omission supraventricular and ventricular arrhythmias . Then the heart rhythm records were studied for daily records and for part of the selected sleep hours - nightly records. The signals discussed above were analyzed using the symbolic method. The goal of these studies was to find differences in the heart rhythm records of the control group and the research group, which could be a kind of dynamical marker that allows prediction if the person will survive the operation. These differences were sought in frequent changes the heart rate acceleration sign, which are defined as the heart rate fragmentation. Analyze by symbolic method consisted in coding the RR interval (time difference between occurrence of consecutive R peaks, which are the signature of the cardiac ventricle contraction) differences by means of symbols: { -1, 0, 1 }, and then dividing the signal into segments of selected lengths (3, 4 and 5). Segments, depending on the length and the occured symbols, were assigned to the appropriate categories of words, which are dependent on the degree of heart rate fragmentation. In order to compare the symbolic method with another examining the heart rate fragmentation, the analysis using the real numbers method was done, which consisted in studying the properties of a series of difference in RR intervals. In the range of this work the necessary algorithms have been implemented in the interactive MATLAB environment. The following were defined: words criteria and parameters determining the degree of heart rate fragmentation.The results were collected and analyzed as a function of age. It was observed that in heart rhythm signals of patients , there are more words with a higher degree of fragmentation than in healthy people . Certain words, which could be classifiers of affiliation aortanil stenosis patients to a research or control group, were found. A comparative analysis was made with results of the work of other authors who studied the heart rate variability with the methods described above. The following thesis describes a novel approach to the study of people heart rhythm, who suffering from aortic stenosis.
Diploma type
Engineer's / Bachelor of Science
Diploma type
Engineer's thesis
Author
Elwira Schneider (FP) Elwira Schneider,, Faculty of Physics (FP)
Title in Polish
Metoda symboliczna analizy stopnia fragmentacji rytmu serca
Supervisor
Jan Żebrowski (FP/PCSD) Jan Żebrowski,, Physics of Complex Systems Divison (FP/PCSD)Faculty of Physics (FP)
Certifying unit
Faculty of Physics (FP)
Affiliation unit
Physics of Complex Systems Divison (FP/PCSD)
Study subject / specialization
, Fizyka Techniczna
Language
(pl) Polish
Status
Finished
Defense Date
11-02-2019
Issue date (year)
2019
Reviewers
Jan Żebrowski (FP/PCSD) Jan Żebrowski,, Physics of Complex Systems Divison (FP/PCSD)Faculty of Physics (FP) Teodor Buchner (FP/PCSD) Teodor Buchner,, Physics of Complex Systems Divison (FP/PCSD)Faculty of Physics (FP)
Keywords in Polish
fragmentacja rytmu serca, metoda symboliczna, wpływ wieku, zmienność rytmu serca
Keywords in English
fragmentation of the heart rhythm, symbolic method, age influence, heart rate variability
Abstract in Polish
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Identyfikator pracy APD: 27256

Uniform Resource Identifier
urn:pw-repo:WUTe955aba32aa0401fb39ee2adc30fdb25