{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,27]],"date-time":"2026-02-27T20:18:37Z","timestamp":1772223517171,"version":"3.50.1"},"reference-count":60,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2025,10,2]],"date-time":"2025-10-02T00:00:00Z","timestamp":1759363200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Committee of Science of the Ministry of Science and Higher Education of the Republic of Kazakhstan","award":["AP26103523"],"award-info":[{"award-number":["AP26103523"]}]}],"content-domain":{"domain":["www.mdpi.com"],"crossmark-restriction":true},"short-container-title":["Eng"],"abstract":"<jats:p>Cardiovascular diseases (CVDs) remain the leading cause of global mortality, with ischemic heart disease (IHD) being the most prevalent and deadly subtype. The growing burden of IHD underscores the urgent need for effective early detection methods that are scalable and non-invasive. Heart Rate Variability (HRV), a non-invasive physiological marker influenced by the autonomic nervous system (ANS), has shown clinical relevance in predicting adverse cardiac events. This study presents a photoplethysmography (PPG)-based Zhurek IoT device, a custom-developed Internet of Things (IoT) device for non-invasive HRV monitoring. The platform\u2019s effectiveness was evaluated using HRV metrics from electrocardiography (ECG) and PPG signals, with machine learning (ML) models applied to the task of early IHD risk detection. ML classifiers were trained on HRV features, and the Random Forest (RF) model achieved the highest classification accuracy of 90.82%, precision of 92.11%, and recall of 91.00% when tested on real data. The model demonstrated excellent discriminative ability with an area under the ROC curve (AUC) of 0.98, reaching a sensitivity of 88% and specificity of 100% at its optimal threshold. The preliminary results suggest that data collected with the \u201cZhurek\u201d IoT devices are promising for the further development of ML models for IHD risk detection. This study aimed to address the limitations of previous work, such as small datasets and a lack of validation, by utilizing real and synthetically augmented data (conditional tabular GAN (CTGAN)), as well as multi-sensor input (ECG and PPG). The findings of this pilot study can serve as a starting point for developing scalable, remote, and cost-effective screening systems. The further integration of wearable devices and intelligent algorithms is a promising direction for improving routine monitoring and advancing preventative cardiology.<\/jats:p>","DOI":"10.3390\/eng6100259","type":"journal-article","created":{"date-parts":[[2025,10,2]],"date-time":"2025-10-02T08:20:28Z","timestamp":1759393228000},"page":"259","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["A Wearable IoT-Based Measurement System for Real-Time Cardiovascular Risk Prediction Using Heart Rate Variability"],"prefix":"10.3390","volume":"6","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3039-6715","authenticated-orcid":false,"given":"Nurdaulet","family":"Tasmurzayev","sequence":"first","affiliation":[{"name":"Faculty of Information Technologies and Artificial Intelligence, Al Farabi Kazakh National University, Almaty 050040, Kazakhstan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4089-6337","authenticated-orcid":false,"given":"Bibars","family":"Amangeldy","sequence":"additional","affiliation":[{"name":"Faculty of Information Technologies and Artificial Intelligence, Al Farabi Kazakh National University, Almaty 050040, Kazakhstan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8865-3676","authenticated-orcid":false,"given":"Timur","family":"Imankulov","sequence":"additional","affiliation":[{"name":"Faculty of Information Technologies and Artificial Intelligence, Al Farabi Kazakh National University, Almaty 050040, Kazakhstan"}]},{"given":"Baglan","family":"Imanbek","sequence":"additional","affiliation":[{"name":"Faculty of Information Technologies and Artificial Intelligence, Al Farabi Kazakh National University, Almaty 050040, Kazakhstan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5055-6347","authenticated-orcid":false,"given":"Octavian Adrian","family":"Postolache","sequence":"additional","affiliation":[{"name":"Department of Information Science and Technology, ISCTE\u2014Instituto Universit\u00e1rio de Lisboa, 1649-026 Lisbon, Portugal"}]},{"given":"Akzhan","family":"Konysbekova","sequence":"additional","affiliation":[{"name":"JSC \u201cResearch Institute of Cardiology and Internal Diseases\u201d, Almaty 050000, Kazakhstan"}]}],"member":"1968","published-online":{"date-parts":[[2025,10,2]]},"reference":[{"key":"ref_1","unstructured":"World Health Organization (2024, June 11). 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