Računalna detekcija QRS kompleksa u uvjetima patoloških promjena u morfologiji signala EKG-a

undergraduate thesis

• Title (english): Computer Based Detection of QRS Complex During Pathology Changes in ECG Signal Morphology
• Author: Hana Ivandić
• Mentor: Mario Cifrek (mentor)
• Committee member: Mario Cifrek (predsjednik povjerenstva)
• Committee member: Krešimir Friganović (član povjerenstva)
• Committee member: Zrinka Topić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; Zagreb
• Defense date and country: 2020-07-03, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Computing

Abstract

Srce je jedan od ključnih organa u ljudskom organizmu. Bez njegovog ispravnog rada znatno se smanjuje kvaliteta života te raste rizik od smrtnog ishoda. Kako bi se neželjene posljedice spriječile, potrebno je na vrijeme otkriti patološke promjene u signalu EKG-a i započeti liječenje. To je moguće ostvariti detekcijom i analizom karakterističnih dijelova signala EKG-a. Korištena je detekcija QRS kompleksa zato što je R zubac najistaknutiji dio svakog otkucaja srca pa ga je relativno jednostavno detektirati.
U ovom radu opisani su građa i aktivnosti srca, analiziran je elektrokardiogram te je objašnjeno njegovo snimanje. Opisana je metoda uklanjanja šuma pomoću valićne transformacije i detekcija QRS kompleksa pomoću transformacije u fazor s osjetljivosti 98,71% i pozitivnom predvidivosti 99,09%. Objašnjena je korištena klasifikacija detektiranih QRS kompleksa metodom k najbližih susjeda kojom su preuranjene ventrikularne kontrakcije izdvojene od normalnih otkucaja. Nakon treniranja klasifikatora nad balansiranim skupom podataka osjetljivost je iznosila 99,15%, a pozitivna predvidivost 96,82% uz manja odstupanja ovisno o slučajno izabranim otkucajima. Nakon treniranja klasifikatora nad nebalansiranim skupom podataka osjetljivost je iznosila 96,63%, a pozitivna predvidivost 99,02%.
Navedene metode implementirane su u programskom paketu MATLAB, dok je testiranje provedeno nad podacima iz MIT-BIH Arrhythmia baze podataka.

Abstract (english)

The heart is one of the key organs of the human body. If its functions were disrupted for any reason, the quality of life is significantly reduced and the risk of death is increased. In order to prevent unwanted consequences, pathological changes in the ECG signal should be detected and the treatment should start as soon as possible. This can be achieved by detecting and analyzing characteristic parts of the ECG signal. QRS complex detection is used because the R peak is the most prominent part of each heartbeat so it is easily detectable.
This paper describes the structure and activities of the heart. It also analyzes the electrocardiogram and how it is obtained. Noise removal using wavelet transform and QRS detection using phasor transform with sensitivity of 98,71% and positive predictivity of 99,09% are explained in detail. The paper also describes the k-nearest neighbors method used for classification of the detected QRS complexes. It distinguishes the premature ventricular contractions from the normal ones. After the training of the classifier on a balanced set of data, obtained sensitivity was 99,15%, and positive predictivity 96,82% with minor deviation depending on the randomly selected beats. After the training of the classifier on an unbalanced set of data, obtained sensitivity was 96,63% and positive predictivity 99,02%.
These methods are implemented in MATLAB software package, while the testing is performed on the data obtained from the MIT-BIH Arrhythmia database.

• Keywords: srce; EKG; valićna transformacija; detekcija QRS kompleksa; metoda k najbližih susjeda (k-NN); PVC
• Keywords (english): heart; ECG; wavelet transform; QRS complex detection; k nearest neighbors (k-NN) method; PVC
• Language: croatian
• URN:NBN: urn:nbn:hr:168:881973
• Study programme: Title: Computing; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka računarstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka računarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2023-01-14 08:56:17