{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T22:33:29Z","timestamp":1790807609707,"version":"4.1.0"},"reference-count":30,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2022,4,9]],"date-time":"2022-04-09T00:00:00Z","timestamp":1649462400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Bioengineering"],"abstract":"<jats:p>Seismocardiography (SCG) is largely regarded as the state-of-the-art technique for continuous, long-term monitoring of cardiac mechanical activity in wearable applications. SCG signals are acquired via small, lightweight accelerometers fixed on the chest. They provide timings of important cardiac events, such as heart valves openings and closures, thus allowing the estimation of cardiac time intervals of clinical relevance. Forcecardiography (FCG) is a novel technique that records the cardiac-induced vibrations of the chest wall by means of specific force sensors, which proved capable of monitoring respiration, heart sounds and infrasonic cardiac vibrations, simultaneously from a single contact point on the chest. A specific infrasonic component captures the heart walls displacements and looks very similar to the Apexcardiogram. This low-frequency component is not visible in SCG recordings, nor it can be extracted by simple filtering. In this study, a feasible way to extract this information from SCG signals is presented. The proposed approach is based on double integration of SCG. Numerical double integration is usually very prone to large errors, therefore a specific numerical procedure was devised. This procedure yields a new displacement signal (DSCG) that features a low-frequency component (LF-DSCG) very similar to that of the FCG (LF-FCG). Experimental tests were carried out using an FCG sensor and an off-the-shelf accelerometer firmly attached to each other and placed onto the precordial region. Simultaneous recordings were acquired from both sensors, together with an electrocardiogram lead (used as a reference). Quantitative morphological comparison confirmed the high similarity between LF-FCG and LF-DSCG (normalized cross-correlation index &gt;0.9). Statistical analyses suggested that LF-DSCG, although achieving a fair sensitivity in heartbeat detection (about 90%), has not a very high consistency within the cardiac cycle, leading to inaccuracies in inter-beat intervals estimation. Future experiments with high-performance accelerometers and improved processing methods are envisioned to investigate the potential enhancement of the accuracy and reliability of the proposed method.<\/jats:p>","DOI":"10.3390\/bioengineering9040167","type":"journal-article","created":{"date-parts":[[2022,4,10]],"date-time":"2022-04-10T06:02:54Z","timestamp":1649570574000},"page":"167","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":27,"title":["A Comparison of Heart Pulsations Provided by Forcecardiography and Double Integration of Seismocardiogram"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4829-3941","authenticated-orcid":false,"given":"Emilio","family":"Andreozzi","sequence":"first","affiliation":[{"name":"Department of Electrical Engineering and Information Technologies, University of Naples Federico II, Via Claudio, 21, 80125 Napoli, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3422-8727","authenticated-orcid":false,"given":"Jessica","family":"Centracchio","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering and Information Technologies, University of Naples Federico II, Via Claudio, 21, 80125 Napoli, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0716-8431","authenticated-orcid":false,"given":"Daniele","family":"Esposito","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering and Information Technologies, University of Naples Federico II, Via Claudio, 21, 80125 Napoli, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9585-971X","authenticated-orcid":false,"given":"Paolo","family":"Bifulco","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering and Information Technologies, University of Naples Federico II, Via Claudio, 21, 80125 Napoli, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,4,9]]},"reference":[{"key":"ref_1","unstructured":"Marey, E.J. (1878). La M\u00e9thode Graphique dans les Sciences Exp\u00e9rimentales, Masson."},{"key":"ref_2","first-page":"533","article-title":"On Certain Molar Movements of the Human Body Produced by the Circulation of Blood","volume":"11","author":"Gordon","year":"1877","journal-title":"J. Anat. Physiol."},{"key":"ref_3","unstructured":"Knoop, A.A. (1962). Experimental Investigations on Ultra-Low Frequency Displacement Ballistocardiography. NASA TT F-269. NASA Contract Rep. NASA CR. National Aeronautics and Space Administration: Washington, DC, USA, 1965; pp. 1\u2013107. Translation of: Experimentele Onderzoekingen over de Ultra-Laagfrequente Verplaatsingballistocardiografie. [Master\u2019s Thesis, Free University of Amsterdam]."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1159\/000410758","article-title":"Assessment of Left Ventricular Function by Noninvasive Methods","volume":"32","author":"Luisada","year":"1985","journal-title":"Adv. Cardiol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"581","DOI":"10.1136\/hrt.24.5.581","article-title":"The Apex Cardiogram in Ischaemic Heart Disease","volume":"24","author":"Benchimol","year":"1962","journal-title":"Heart"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1152\/ajplegacy.1939.127.1.1","article-title":"Studies on the estimation of cardiac output in man, and of abnormalities in cardiac function, from the heart\u2019s recoil and the blood\u2019s impacts; the ballistocardiogram","volume":"127","author":"Starr","year":"1939","journal-title":"Am. J. Physiol."},{"key":"ref_7","first-page":"111","article-title":"Seismocardiography: A new technique for recording cardiac vibrations. Concept, method, and initial observations","volume":"9","author":"Zanetti","year":"1990","journal-title":"J. Cardiovasc. Technol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1414","DOI":"10.1109\/JBHI.2014.2361732","article-title":"Ballistocardiography and Seismocardiography: A Review of Recent Advances","volume":"19","author":"Inan","year":"2015","journal-title":"IEEE J. Biomed. Health Inform."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"64","DOI":"10.3390\/vibration2010005","article-title":"Recent Advances in Seismocardiography","volume":"2","author":"Taebi","year":"2019","journal-title":"Vibration"},{"key":"ref_10","unstructured":"Bifulco, P., Gargiulo, G.D., D\u2019Angelo, G., Liccardo, A., Romano, M., Clemente, F., and Cesarelli, M. (2014, January 15\u201317). Monitoring of respiration, seismocardiogram and heart sounds by a PVDF piezo film sensor. Proceedings of the 20th IMEKO TC4 Symposium on Measurements of Electrical Quantities: Research on Electrical and Electronic Measurement for the Economic Upturn, Together with 18th TC4 International Workshop on ADC and DCA Modeling and Testing, Benevento, Italy."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Andreozzi, E., Fratini, A., Esposito, D., Naik, G., Polley, C., Gargiulo, G.D., and Bifulco, P. (2020). Forcecardiography: A Novel Technique to Measure Heart Mechanical Vibrations onto the Chest Wall. Sensors, 20.","DOI":"10.3390\/s20143885"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Esposito, D., Andreozzi, E., Fratini, A., Gargiulo, G., Savino, S., Niola, V., and Bifulco, P. (2018). A Piezoresistive Sensor to Measure Muscle Contraction and Mechanomyography. Sensors, 18.","DOI":"10.3390\/s18082553"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Esposito, D., Andreozzi, E., Gargiulo, G.D., Fratini, A., D\u2019Addio, G., Naik, G.R., and Bifulco, P. (2020). A Piezoresistive Array Armband with Reduced Number of Sensors for Hand Gesture Recognition. Front. Neurorobot., 13.","DOI":"10.3389\/fnbot.2019.00114"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Esposito, D., Gargiulo, G.D., Parajuli, N., Cesarelli, G., Andreozzi, E., and Bifulco, P. (July, January 1). Measurement of muscle contraction timing for prosthesis control: A comparison between electromyography and force-myography. Proceedings of the 2020 IEEE International Symposium on Medical Measurements and Applications (MeMeA), Bari, Italy.","DOI":"10.1109\/MeMeA49120.2020.9137313"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Andreozzi, E., Centracchio, J., Punzo, V., Esposito, D., Polley, C., Gargiulo, G.D., and Bifulco, P. (2021). Respiration Monitoring via Forcecardiography Sensors. Sensors, 21.","DOI":"10.3390\/s21123996"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3389\/fphys.2021.725716","article-title":"A Novel Broadband Forcecardiography Sensor for Simultaneous Monitoring of Respiration, Infrasonic Cardiac Vibrations and Heart Sounds","volume":"12","author":"Andreozzi","year":"2021","journal-title":"Front. Physiol."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Centracchio, J., Andreozzi, E., Esposito, D., Gargiulo, G.D., and Bifulco, P. (2022). Detection of Aortic Valve Opening and Estimation of Pre-Ejection Period in Forcecardiography Recordings. Bioengineering, 9.","DOI":"10.3390\/bioengineering9030089"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1627","DOI":"10.1021\/ac60214a047","article-title":"Smoothing and Differentiation of Data by Simplified Least Squares Procedures","volume":"36","author":"Savitzky","year":"1964","journal-title":"Anal. Chem."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"671","DOI":"10.21105\/joss.00671","article-title":"BioSigKit: A Matlab Toolbox and Interface for Analysis of BioSignals","volume":"3","author":"Sedghamiz","year":"2018","journal-title":"J. Open Source Softw."},{"key":"ref_20","unstructured":"Ran, K. (2020, May 28). Bland-Altman and Correlation Plot, MATLAB Central File Exchange. Available online: https:\/\/www.mathworks.com\/matlabcentral\/fileexchange\/45049-bland-altman-and-correlation-plot."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"697","DOI":"10.1136\/hrt.25.6.697","article-title":"The apex cardiogram: Its normal features explained by those found in heart disease","volume":"25","author":"Coulshed","year":"1963","journal-title":"Heart"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"647","DOI":"10.1016\/0002-9149(65)90351-6","article-title":"Correlation between the apex cardiogram and left ventricular pressure","volume":"15","author":"Rios","year":"1965","journal-title":"Am. J. Cardiol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"829","DOI":"10.1136\/hrt.27.6.829","article-title":"The apex cardiogram and its relationship to haemodynamic events within the left heart","volume":"27","author":"Tavel","year":"1965","journal-title":"Heart"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1015","DOI":"10.1161\/01.CIR.41.6.1015","article-title":"The Use of Apexcardiography in the Assessment of Left Ventricular Diastolic Pressure","volume":"41","author":"Voigt","year":"1970","journal-title":"Circulation"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1016\/0002-9149(71)90035-X","article-title":"On the value of apex cardiography for timing intracardiac events","volume":"28","author":"Willems","year":"1971","journal-title":"Am. J. Cardiol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1263","DOI":"10.1136\/hrt.37.12.1263","article-title":"Time relation between apex cardiogram and left ventricular events using simultaneous high-fidelity tracings in man","volume":"37","author":"Manolas","year":"1975","journal-title":"Heart"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"692","DOI":"10.1161\/01.CIR.57.4.692","article-title":"Comparison between apexcardiographic and angiographic indexes of left ventricular performance in patients with aortic incompetence","volume":"57","author":"Manolas","year":"1978","journal-title":"Circulation"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"736","DOI":"10.1016\/0002-9149(81)90153-3","article-title":"Diastolic amplitude time index: A new apexcardiographic index of left ventricular diastolic function in human beings","volume":"48","author":"Manolas","year":"1981","journal-title":"Am. J. Cardiol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"73","DOI":"10.1016\/j.measurement.2004.04.005","article-title":"Numerical double integration of acceleration measurements in noise","volume":"36","author":"Thong","year":"2004","journal-title":"Measurement"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Migeotte, P.-F., Mucci, V., Deli\u00e8re, Q., Lejeune, L., and van de Borne, P. (April, January 31). Multi-dimensional Kineticardiography a New Approach for Wearable Cardiac Monitoring Through Body Acceleration Recordings. Proceedings of the XIV Mediterranean Conference on Medical and Biological Engineering and Computing 2016, MEDICON 2016, Paphos, Cyprus.","DOI":"10.1007\/978-3-319-32703-7_220"}],"container-title":["Bioengineering"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2306-5354\/9\/4\/167\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T22:51:09Z","timestamp":1760136669000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2306-5354\/9\/4\/167"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,4,9]]},"references-count":30,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2022,4]]}},"alternative-id":["bioengineering9040167"],"URL":"https:\/\/doi.org\/10.3390\/bioengineering9040167","relation":{},"ISSN":["2306-5354"],"issn-type":[{"value":"2306-5354","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,4,9]]}}}