Accurate Localization of First and Second Heart Sounds via Template Matching in Forcecardiography Signals
Cardiac auscultation is an essential part of physical examination and plays a key role in the early diagnosis of many cardiovascular diseases. The analysis of phonocardiography (PCG) recordings is generally based on the recognition of the main heart sounds, i.e., S1 and S2, which is not a trivial ta...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2024-02-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/24/5/1525 |
| _version_ | 1827319371215667200 |
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| author | Jessica Centracchio Salvatore Parlato Daniele Esposito Emilio Andreozzi |
| author_facet | Jessica Centracchio Salvatore Parlato Daniele Esposito Emilio Andreozzi |
| author_sort | Jessica Centracchio |
| collection | DOAJ |
| description | Cardiac auscultation is an essential part of physical examination and plays a key role in the early diagnosis of many cardiovascular diseases. The analysis of phonocardiography (PCG) recordings is generally based on the recognition of the main heart sounds, i.e., S1 and S2, which is not a trivial task. This study proposes a method for an accurate recognition and localization of heart sounds in Forcecardiography (FCG) recordings. FCG is a novel technique able to measure subsonic vibrations and sounds via small force sensors placed onto a subject’s thorax, allowing continuous cardio-respiratory monitoring. In this study, a template-matching technique based on normalized cross-correlation was used to automatically recognize heart sounds in FCG signals recorded from six healthy subjects at rest. Distinct templates were manually selected from each FCG recording and used to separately localize S1 and S2 sounds, as well as S1–S2 pairs. A simultaneously recorded electrocardiography (ECG) trace was used for performance evaluation. The results show that the template matching approach proved capable of separately classifying S1 and S2 sounds in more than 96% of all heartbeats. Linear regression, correlation, and Bland–Altman analyses showed that inter-beat intervals were estimated with high accuracy. Indeed, the estimation error was confined within 10 ms, with negligible impact on heart rate estimation. Heart rate variability (HRV) indices were also computed and turned out to be almost comparable with those obtained from ECG. The preliminary yet encouraging results of this study suggest that the template matching approach based on normalized cross-correlation allows very accurate heart sounds localization and inter-beat intervals estimation. |
| first_indexed | 2024-04-25T00:20:13Z |
| format | Article |
| id | doaj.art-896e9ae4242441c0bcf28f645a016811 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-04-25T00:20:13Z |
| publishDate | 2024-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-896e9ae4242441c0bcf28f645a0168112024-03-12T16:55:05ZengMDPI AGSensors1424-82202024-02-01245152510.3390/s24051525Accurate Localization of First and Second Heart Sounds via Template Matching in Forcecardiography SignalsJessica Centracchio0Salvatore Parlato1Daniele Esposito2Emilio Andreozzi3Department of Electrical Engineering and Information Technologies, University of Naples Federico II, Via Claudio, 21, I-80125 Naples, ItalyDepartment of Electrical Engineering and Information Technologies, University of Naples Federico II, Via Claudio, 21, I-80125 Naples, ItalyDepartment of Electrical Engineering and Information Technologies, University of Naples Federico II, Via Claudio, 21, I-80125 Naples, ItalyDepartment of Electrical Engineering and Information Technologies, University of Naples Federico II, Via Claudio, 21, I-80125 Naples, ItalyCardiac auscultation is an essential part of physical examination and plays a key role in the early diagnosis of many cardiovascular diseases. The analysis of phonocardiography (PCG) recordings is generally based on the recognition of the main heart sounds, i.e., S1 and S2, which is not a trivial task. This study proposes a method for an accurate recognition and localization of heart sounds in Forcecardiography (FCG) recordings. FCG is a novel technique able to measure subsonic vibrations and sounds via small force sensors placed onto a subject’s thorax, allowing continuous cardio-respiratory monitoring. In this study, a template-matching technique based on normalized cross-correlation was used to automatically recognize heart sounds in FCG signals recorded from six healthy subjects at rest. Distinct templates were manually selected from each FCG recording and used to separately localize S1 and S2 sounds, as well as S1–S2 pairs. A simultaneously recorded electrocardiography (ECG) trace was used for performance evaluation. The results show that the template matching approach proved capable of separately classifying S1 and S2 sounds in more than 96% of all heartbeats. Linear regression, correlation, and Bland–Altman analyses showed that inter-beat intervals were estimated with high accuracy. Indeed, the estimation error was confined within 10 ms, with negligible impact on heart rate estimation. Heart rate variability (HRV) indices were also computed and turned out to be almost comparable with those obtained from ECG. The preliminary yet encouraging results of this study suggest that the template matching approach based on normalized cross-correlation allows very accurate heart sounds localization and inter-beat intervals estimation.https://www.mdpi.com/1424-8220/24/5/1525heart soundsforcecardiographytemplate matchingnormalized cross-correlationheart rate variability |
| spellingShingle | Jessica Centracchio Salvatore Parlato Daniele Esposito Emilio Andreozzi Accurate Localization of First and Second Heart Sounds via Template Matching in Forcecardiography Signals Sensors heart sounds forcecardiography template matching normalized cross-correlation heart rate variability |
| title | Accurate Localization of First and Second Heart Sounds via Template Matching in Forcecardiography Signals |
| title_full | Accurate Localization of First and Second Heart Sounds via Template Matching in Forcecardiography Signals |
| title_fullStr | Accurate Localization of First and Second Heart Sounds via Template Matching in Forcecardiography Signals |
| title_full_unstemmed | Accurate Localization of First and Second Heart Sounds via Template Matching in Forcecardiography Signals |
| title_short | Accurate Localization of First and Second Heart Sounds via Template Matching in Forcecardiography Signals |
| title_sort | accurate localization of first and second heart sounds via template matching in forcecardiography signals |
| topic | heart sounds forcecardiography template matching normalized cross-correlation heart rate variability |
| url | https://www.mdpi.com/1424-8220/24/5/1525 |
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