{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T08:01:38Z","timestamp":1788854498233,"version":"build-2803163510"},"reference-count":36,"publisher":"Oxford University Press (OUP)","issue":"4","license":[{"start":{"date-parts":[[2025,2,17]],"date-time":"2025-02-17T00:00:00Z","timestamp":1739750400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001858","name":"VINNOVA","doi-asserted-by":"publisher","award":["2019\u201301378"],"award-info":[{"award-number":["2019\u201301378"]}],"id":[{"id":"10.13039\/501100001858","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001858","name":"VINNOVA","doi-asserted-by":"publisher","award":["2020-00896"],"award-info":[{"award-number":["2020-00896"]}],"id":[{"id":"10.13039\/501100001858","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004348","name":"Stockholm County Council","doi-asserted-by":"publisher","award":["20190268"],"award-info":[{"award-number":["20190268"]}],"id":[{"id":"10.13039\/501100004348","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004348","name":"Stockholm County Council","doi-asserted-by":"publisher","award":["20191140"],"award-info":[{"award-number":["20191140"]}],"id":[{"id":"10.13039\/501100004348","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003793","name":"Swedish Heart-Lung Foundation","doi-asserted-by":"publisher","award":["20230327"],"award-info":[{"award-number":["20230327"]}],"id":[{"id":"10.13039\/501100003793","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2025,3,28]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:sec>\n                  <jats:title>Aims<\/jats:title>\n                  <jats:p>The aim of this study was to perform an external validation of an automatic machine learning (ML) algorithm for heart rhythm diagnostics using smartphone photoplethysmography (PPG) recorded by patients with atrial fibrillation (AF) and atrial flutter (AFL) pericardioversion in an unsupervised ambulatory setting.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Methods and results<\/jats:title>\n                  <jats:p>Patients undergoing cardioversion for AF or AFL performed 1-min heart rhythm recordings pericardioversion at least twice daily for 4\u20136 weeks, using an iPhone 7 smartphone running a PPG application (CORAI Heart Monitor) simultaneously with a single-lead electrocardiogram (ECG) recording (KardiaMobile). The algorithm uses support vector machines to classify heart rhythm from smartphone-PPG. The algorithm was trained on PPG recordings made by patients in a separate cardioversion cohort. Photoplethysmography recordings in the external validation cohort were analysed by the algorithm. Diagnostic performance was calculated by comparing the heart rhythm classification output to the diagnosis from the simultaneous ECG recordings (gold standard). In total, 460 patients performed 34 097 simultaneous PPG and ECG recordings, divided into 180 patients with 16 092 recordings in the training cohort and 280 patients with 18 005 recordings in the external validation cohort. Algorithmic classification of the PPG recordings in the external validation cohort diagnosed AF with sensitivity, specificity, and accuracy of 99.7%, 99.7% and 99.7%, respectively, and AF\/AFL with sensitivity, specificity, and accuracy of 99.3%, 99.1% and 99.2%, respectively.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Conclusion<\/jats:title>\n                  <jats:p>A machine learning-based algorithm demonstrated excellent performance in diagnosing atrial fibrillation and atrial flutter from smartphone-PPG recordings in an unsupervised ambulatory setting, minimizing the need for manual review and ECG verification, in elderly cardioversion populations.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Clinical Trial Registration<\/jats:title>\n                  <jats:p>Clinicaltrials.gov, NCT04300270<\/jats:p>\n               <\/jats:sec>","DOI":"10.1093\/europace\/euaf031","type":"journal-article","created":{"date-parts":[[2025,2,17]],"date-time":"2025-02-17T15:24:51Z","timestamp":1739805891000},"source":"Crossref","is-referenced-by-count":9,"title":["External validation of a machine learning-based classification algorithm for ambulatory heart rhythm diagnostics in pericardioversion atrial fibrillation patients using smartphone photoplethysmography: the SMARTBEATS-ALGO study"],"prefix":"10.1093","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3678-8050","authenticated-orcid":false,"given":"Jonatan","family":"Fernstad","sequence":"first","affiliation":[{"name":"Karolinska Institutet, Department of Clinical Sciences, Danderyd University Hospital , Entr\u00e9v\u00e4gen 2, 182 88 Stockholm ,","place":["Sweden"]},{"name":"Department of Cardiology, Danderyd University Hospital , Entr\u00e9v\u00e4gen 2, 182 88 Stockholm ,","place":["Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6413-0870","authenticated-orcid":false,"given":"Emma","family":"Svennberg","sequence":"additional","affiliation":[{"name":"Karolinska Institutet, Department of Medicine, Huddinge, Karolinska University Hospital , Stockholm ,","place":["Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-7361-6992","authenticated-orcid":false,"given":"Peter","family":"\u00c5berg","sequence":"additional","affiliation":[{"name":"Karolinska Institutet, Department of Clinical Sciences, Danderyd University Hospital , Entr\u00e9v\u00e4gen 2, 182 88 Stockholm ,","place":["Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5106-749X","authenticated-orcid":false,"given":"Katrin","family":"Kemp Gudmundsdottir","sequence":"additional","affiliation":[{"name":"Karolinska Institutet, Department of Clinical Sciences, Danderyd University Hospital , Entr\u00e9v\u00e4gen 2, 182 88 Stockholm ,","place":["Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0370-1956","authenticated-orcid":false,"given":"Anders","family":"Jansson","sequence":"additional","affiliation":[{"name":"Department of Clinical Physiology, Danderyd University Hospital , Stockholm ,","place":["Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1677-7215","authenticated-orcid":false,"given":"Johan","family":"Engdahl","sequence":"additional","affiliation":[{"name":"Karolinska Institutet, Department of Clinical Sciences, Danderyd University Hospital , Entr\u00e9v\u00e4gen 2, 182 88 Stockholm ,","place":["Sweden"]},{"name":"Department of Cardiology, Danderyd University Hospital , Entr\u00e9v\u00e4gen 2, 182 88 Stockholm ,","place":["Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2025,2,17]]},"reference":[{"key":"2025052712573939800_euaf031-B1","doi-asserted-by":"crossref","first-page":"404","DOI":"10.1038\/s41569-022-00820-8","article-title":"Epidemiology and modifiable risk factors for atrial fibrillation","volume":"20","author":"Elliott","year":"2023","journal-title":"Nat Rev Cardiol"},{"key":"2025052712573939800_euaf031-B2","doi-asserted-by":"crossref","first-page":"983","DOI":"10.1161\/01.STR.22.8.983","article-title":"Atrial fibrillation as an independent risk factor for stroke: the Framingham study","volume":"22","author":"Wolf","year":"1991","journal-title":"Stroke"},{"key":"2025052712573939800_euaf031-B3","doi-asserted-by":"crossref","first-page":"857","DOI":"10.7326\/0003-4819-146-12-200706190-00007","article-title":"Meta-analysis: antithrombotic therapy to prevent stroke in patients who have nonvalvular atrial fibrillation","volume":"146","author":"Hart","year":"2007","journal-title":"Ann Intern Med"},{"key":"2025052712573939800_euaf031-B4","doi-asserted-by":"crossref","first-page":"453","DOI":"10.1093\/eurheartj\/ehx579","article-title":"Less dementia with oral anticoagulation in atrial fibrillation","volume":"39","author":"Friberg","year":"2018","journal-title":"Eur Heart J"},{"key":"2025052712573939800_euaf031-B5","doi-asserted-by":"crossref","first-page":"3314","DOI":"10.1093\/eurheartj\/ehae176","article-title":"2024 ESC guidelines for the management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS)","volume":"45","author":"Van Gelder","year":"2024","journal-title":"Eur Heart J"},{"key":"2025052712573939800_euaf031-B6","doi-asserted-by":"crossref","first-page":"979","DOI":"10.1093\/europace\/euac038","article-title":"How to use digital devices to detect and manage arrhythmias: an EHRA practical guide","volume":"24","author":"Svennberg","year":"2022","journal-title":"Europace"},{"key":"2025052712573939800_euaf031-B7","doi-asserted-by":"crossref","first-page":"euae079","DOI":"10.1093\/europace\/euae079","article-title":"Validation of a novel smartphone-based photoplethysmographic method for ambulatory heart rhythm diagnostics: the SMARTBEATS study","volume":"26","author":"Fernstad","year":"2024","journal-title":"Europace"},{"key":"2025052712573939800_euaf031-B8","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1016\/j.hroo.2020.02.005","article-title":"Review of mobile applications for the detection and management of atrial fibrillation","volume":"1","author":"Turchioe","year":"2020","journal-title":"Heart Rhythm O2"},{"key":"2025052712573939800_euaf031-B9","doi-asserted-by":"crossref","first-page":"1600","DOI":"10.1136\/heartjnl-2021-320417","article-title":"Smartphone detection of atrial fibrillation using photoplethysmography: a systematic review and meta-analysis","volume":"108","author":"Gill","year":"2022","journal-title":"Heart"},{"key":"2025052712573939800_euaf031-B10","doi-asserted-by":"crossref","first-page":"e202064","DOI":"10.1001\/jamanetworkopen.2020.2064","article-title":"Accuracy of smartphone camera applications for detecting atrial fibrillation: a systematic review and meta-analysis","volume":"3","author":"O\u2019Sullivan","year":"2020","journal-title":"JAMA Netw Open"},{"key":"2025052712573939800_euaf031-B11","doi-asserted-by":"crossref","first-page":"e1","DOI":"10.1161\/CIR.0000000000001193","article-title":"2023 ACC\/AHA\/ACCP\/HRS guideline for the diagnosis and management of atrial fibrillation: a report of the American College of Cardiology\/American Heart Association Joint Committee on Clinical Practice Guidelines","volume":"149","author":"Joglar","year":"2023","journal-title":"Circulation"},{"key":"2025052712573939800_euaf031-B12","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1093\/europace\/euy176","article-title":"Detection of atrial fibrillation with a smartphone camera: first prospective, international, two-centre, clinical validation study (DETECT AF PRO)","volume":"21","author":"Brasier","year":"2019","journal-title":"Europace"},{"key":"2025052712573939800_euaf031-B13","doi-asserted-by":"crossref","first-page":"e12284","DOI":"10.2196\/12284","article-title":"Mobile phone\u2013based use of the photoplethysmography technique to detect atrial fibrillation in primary care: diagnostic accuracy study of the fibricheck app","volume":"7","author":"Proesmans","year":"2019","journal-title":"JMIR Mhealth Uhealth"},{"key":"2025052712573939800_euaf031-B14","doi-asserted-by":"crossref","first-page":"euad176","DOI":"10.1093\/europace\/euad176","article-title":"The digital journey: 25 years of digital development in electrophysiology from an Europace perspective","volume":"25","author":"Svennberg","year":"2023","journal-title":"Europace"},{"key":"2025052712573939800_euaf031-B15","doi-asserted-by":"crossref","first-page":"403","DOI":"10.1370\/afm.2438","article-title":"Diagnostic accuracy of a smartphone-operated, single-lead electrocardiography device for detection of rhythm and conduction abnormalities in primary care","volume":"17","author":"Himmelreich","year":"2019","journal-title":"Ann Fam Med"},{"key":"2025052712573939800_euaf031-B16","first-page":"70","article-title":"The effectiveness of a mobile ECG device in identifying AF: sensitivity, specificity and predictive value","volume":"22","author":"Williams","year":"2015","journal-title":"Br J Cardiol"},{"key":"2025052712573939800_euaf031-B17","doi-asserted-by":"crossref","first-page":"884","DOI":"10.1016\/j.jelectrocard.2018.07.008","article-title":"Modified positioning of a smartphone based single-lead electrocardiogram device improves detection of atrial flutter","volume":"51","author":"Rajakariar","year":"2018","journal-title":"J Electrocardiol"},{"key":"2025052712573939800_euaf031-B18","doi-asserted-by":"crossref","first-page":"144","DOI":"10.1145\/130385.130401","article-title":"A training algorithm for optimal margin classifiers","author":"Boser","year":"1992","journal-title":"Proc Fifth Annu Workshop Comput Learn Theory"},{"key":"2025052712573939800_euaf031-B19"},{"key":"2025052712573939800_euaf031-B20","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1093\/jamia\/ocad219","article-title":"Automatic segmentation of atrial fibrillation and flutter in single-lead electrocardiograms by self-supervised learning and transformer architecture","volume":"31","author":"Yun","year":"2024","journal-title":"J Am Med Inform Assoc"},{"key":"2025052712573939800_euaf031-B21","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1080\/17434440.2023.2171290","article-title":"Validation of diagnostic accuracy of a handheld, smartphone-based rhythm recording device","volume":"20","author":"Paul Nordin","year":"2023","journal-title":"Expert Rev Med Devices"},{"key":"2025052712573939800_euaf031-B22","first-page":"2579","article-title":"Visualizing data using t-SNE","volume":"9","author":"Van Der Maaten","year":"2008","journal-title":"J Mach Learn Res"},{"key":"2025052712573939800_euaf031-B23","doi-asserted-by":"crossref","first-page":"1784","DOI":"10.1161\/CIRCULATIONAHA.117.030583","article-title":"Assessment of remote heart rhythm sampling using the AliveCor heart monitor to screen for atrial fibrillation","volume":"136","author":"Halcox","year":"2017","journal-title":"Circulation"},{"key":"2025052712573939800_euaf031-B24","doi-asserted-by":"crossref","first-page":"euae065","DOI":"10.1093\/europace\/euae065","article-title":"Real-world validation of smartphone-based photoplethysmography for rate and rhythm monitoring in atrial fibrillation","volume":"26","author":"Gruwez","year":"2024","journal-title":"Europace"},{"key":"2025052712573939800_euaf031-B25","doi-asserted-by":"crossref","first-page":"4","DOI":"10.1038\/s41746-020-00367-3","article-title":"Second opinion needed: communicating uncertainty in medical machine learning","volume":"4","author":"Kompa","year":"2021","journal-title":"NPJ Digit Med Nat Res"},{"key":"2025052712573939800_euaf031-B26","doi-asserted-by":"crossref","first-page":"711","DOI":"10.1038\/s41551-022-00988-x","article-title":"Tackling prediction uncertainty in machine learning for healthcare","volume":"7","author":"Chua","year":"2023","journal-title":"Nat Biomed Eng"},{"key":"2025052712573939800_euaf031-B27","doi-asserted-by":"crossref","first-page":"1834","DOI":"10.1161\/CIRCULATIONAHA.119.040267","article-title":"Searching for atrial fibrillation poststroke: a white paper of the AF-SCREEN International Collaboration","volume":"140","author":"Schnabel","year":"2019","journal-title":"Circulation"},{"key":"2025052712573939800_euaf031-B28","doi-asserted-by":"crossref","first-page":"474","DOI":"10.1111\/joim.13217","article-title":"Large-scale screening studies for atrial fibrillation \u2013 is it worth the effort?","volume":"289","author":"Engdahl","year":"2021","journal-title":"J Intern Med"},{"key":"2025052712573939800_euaf031-B29","doi-asserted-by":"crossref","first-page":"1167","DOI":"10.1093\/europace\/euz119","article-title":"Atrial fibrillation screening with photo-plethysmography through a smartphone camera","volume":"21","author":"Verbrugge","year":"2019","journal-title":"Europace"},{"key":"2025052712573939800_euaf031-B30","doi-asserted-by":"crossref","first-page":"464","DOI":"10.1093\/ehjdh\/ztad054","article-title":"Smartphone-based atrial fibrillation screening in the general population: feasibility and impact on medical treatment","volume":"4","author":"Gruwez","year":"2023","journal-title":"Eur Heart J Digit Health"},{"key":"2025052712573939800_euaf031-B31","doi-asserted-by":"crossref","first-page":"1823","DOI":"10.1038\/s41591-022-01979-w","article-title":"Smartphone-based screening for atrial fibrillation: a pragmatic randomized clinical trial","volume":"28","author":"Rizas","year":"2022","journal-title":"Nat Med Nat Res"},{"key":"2025052712573939800_euaf031-B32","doi-asserted-by":"crossref","first-page":"e003428","DOI":"10.1161\/JAHA.116.003428","article-title":"Diagnostic performance of a smartphone-based photoplethysmographic application for atrial fibrillation screening in a primary care setting","volume":"5","author":"Chan","year":"2016","journal-title":"J Am Heart Assoc"},{"key":"2025052712573939800_euaf031-B33","doi-asserted-by":"crossref","first-page":"51","DOI":"10.1111\/jce.12842","article-title":"PULSE-SMART: pulse-based arrhythmia discrimination using a novel smartphone application","volume":"27","author":"McManus","year":"2016","journal-title":"J Cardiovasc Electrophysiol"},{"key":"2025052712573939800_euaf031-B34","doi-asserted-by":"crossref","first-page":"412","DOI":"10.1093\/eurjcn\/zvac061","article-title":"Patient motivation and adherence to an on-demand app-based heart rate and rhythm monitoring for atrial fibrillation management: data from the TeleCheck-AF project","volume":"22","author":"Gawa\u0142ko","year":"2023","journal-title":"Eur J Cardiovasc Nurs"},{"key":"2025052712573939800_euaf031-B35","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1016\/j.ejim.2019.11.018","article-title":"Prospective blinded evaluation of the smartphone-based AliveCor Kardia ECG monitor for atrial fibrillation detection: the PEAK-AF study","volume":"73","author":"Wegner","year":"2020","journal-title":"Eur J Intern Med"},{"key":"2025052712573939800_euaf031-B36","doi-asserted-by":"crossref","first-page":"835","DOI":"10.1093\/europace\/euad011","article-title":"Accuracy of continuous photoplethysmography-based 1\u2005min mean heart rate assessment during atrial fibrillation","volume":"25","author":"Hermans","year":"2023","journal-title":"Europace"}],"container-title":["Europace"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/academic.oup.com\/europace\/advance-article-pdf\/doi\/10.1093\/europace\/euaf031\/61930774\/euaf031.pdf","content-type":"application\/pdf","content-version":"am","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/europace\/article-pdf\/27\/4\/euaf031\/61930774\/euaf031.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/europace\/article-pdf\/27\/4\/euaf031\/61930774\/euaf031.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,5,27]],"date-time":"2025-05-27T16:59:11Z","timestamp":1748365151000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/europace\/article\/doi\/10.1093\/europace\/euaf031\/8019564"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,2,17]]},"references-count":36,"journal-issue":{"issue":"4","published-print":{"date-parts":[[2025,3,28]]}},"URL":"https:\/\/doi.org\/10.1093\/europace\/euaf031","relation":{},"ISSN":["1099-5129","1532-2092"],"issn-type":[{"value":"1099-5129","type":"print"},{"value":"1532-2092","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[2025,4]]},"published":{"date-parts":[[2025,2,17]]},"article-number":"euaf031"}}