7.1 Early diagnosis of atherosclerosis
Developed a new methodology for early diagnosis of atherosclerosis based on optical non-invasive determination of dynamic compliance of arteries. Novelty compared to international excellence is within a dramatic improvement of time in simultaneous and quick optical registration of mechanical movements of arteries walls, pulse wave velocity and shape, and dynamics of blood pressure creates a system of parameters for estimation of dynamic compliance of arteries and to get early diagnoses of atherosclerosis.
Cooperation: North Estonia Medical Center, Tallinn (Estonia), Optoelectronics and Measurement Techniques Laboratory, University of Oulu, Centre for Integrated Electronic Systems and Biomedical Engineering (CEBE).
PhD students: K. Temitski, G.Zemtsovskaja, M.Pikta
1. Viigimaa M, Talvik A, Wojciechowska W, Kawecka-Jaszcz K, Toft I, Stergiou GS, Nasothimiou EG, Kotsis V, Agabiti Rosei E, Salvetti M, Dorobantu M, Martell-Claros N, Abad-Cardiel M, Hernández-Hernández R, Doménech M, Coca A. (2013) Identification of the hemodynamic modulators and hemodynamic status in uncontrolled hypertensive patients. Blood Press. 22(6):362-70.
2. White HD, Held C, Stewart R, Tarka E, Brown R, Viigimaa M et al. (2014) Darapladib for preventing ischemic events in stable coronary heart disease N Engl J Med. 370(18):1702-11. doi: 10.1056/NEJMoa1315878. Epub 2014 Mar 30.
3. Kaldmäe M, Viigimaa M, Zemtsovskaja G, Kaart T, Abina J, Annuk M. (2014) Prevalence and determinants of hypertension in Estonian adults. Scand J Public Health. 42(6):504-510.
4. Jensen-Urstad M, Viigimaa M, Sammul S, Lenhoff H, Johansson J. (2014) Impact of smoking: All-cause and cardiovascular mortality in a cohort of 55-year-old Swedes and Estonians. Scand J Public Health. 42(8):780-5.
Implementation: Developed and designed a new device for PPG signal acquisition. Pilot clinical studies of patients with diabetes mellitus performed in North Estonian Regional Hospital using the new device.
1. K Pilt, K Meigas, R Ferenets, K Temitski, and M Viigimaa (2014) Photoplethysmographic signal waveform index for detection of increased arterial stiffness. Physiological Measurements, 35, 2027–2036.
7.2 Signal processing methods
The ability to identify premature arterial stiffening is of considerable value in the prevention of cardiovascular diseases. The new second derivative photoplethysmographic (PPG) analysis algorithm was developed with optimal filtering and signal normalization in time. In addition the algorithm for PPG signal waveform rising front analysis was developed in order to discriminate subjects with premature increase in arterial ageing. The algorithms were tested on 21 healthy subjects and 20 diabetes patients. Significant differences were found between the healthy controls and diabetes patients. We conclude that the PPG technology with the advanced signal processing algorithms can be used for the discrimination of subjects with increased arterial ageing. Those methodologies give the possibility to diagnose cardiovascular diseases in an early stadium. The project P3 is initiated based on the developed algorithms and results.
Cooperation: North Estonia Medical Center, Tallinn (Estonia), Optoelectronics and Measurement Techniques Laboratory, University of Oulu, Department of Biomedical Engineering, Linköping University, Centre for Integrated Electronic Systems and Biomedical Engineering (CEBE).
PhD thesis: Kristjan Pilt 2014.
1. K Pilt, R Ferenets, K Meigas, L-G Lindberg, K Temitski, M Viigimaa (2013). New Photoplethysmographic Signal Analysis Algorithm for Arterial Stiffness Estimation. The Scientific World Journal, 2013, 9 pp.
2. Pilt, Kristjan; Meigas, Kalju; Kööts, Kristina; Viigimaa, Margus (2014). Photoplethysmographic signal rising front analysis for the discrimination of subjects with increased arterial ageing. Proceedings of the Estonian Academy of Sciences, 63(3), 221-226.
3. Pilt, Kristjan; Kööts, Kristina; Meigas, Kalju; Šamarin, Andrei; Zemtsovskaja, Galina; Viigimaa, Margus (2015). The Aortic Pulse Wave Velocity Estimation for Arterial Stiffness Assessment. In: IFMBE Proceedings: MBEC 2014, Dubrovnik, 7-11 September 2014. IFMBE, 294-297.
7.3 Continuous and non-invasive optical monitoring of blood pressure
Developed a new methodology for continuous and non-invasive optical monitoring of blood pressure based on pulse wave transit time measurements between different regions of human body. The novelty can be regarded in the method utilizes changes of pulse wave arrival time as an indicator of changes in systolic blood pressure. Two new projects in cooperation with ESA “Feasibility Study of the Heart Rate and Cuff-Less Blood Circulation Holter Device for Non-Invasive, Simultaneous and Continuous Monitoring of Cardiovascular Parameters on the Earth and in the Space” (2012-2013) and “Development of the Heart Rate and Cuff‐less Blood Circulation Holter Device for Non‐invasive, Simultaneous and Continuous Monitoring of Cardiovascular Parameters on the Earth and in Space” (2014-2015) were successfully performed and laboratory device for continuous and non-invasive blood pressure measurements designed.
Cooperation: North Estonia Medical Center, Tallinn (Estonia), Optoelectronics and Measurement Techniques Laboratory, University of Oulu, Tensiotrace OÜ, Centre for Integrated Electronic Systems and Biomedical Engineering (CEBE).
PhD student: V.Vassiljev (expected defence in 2017)
1. Estonian patent EE05619B1 (granted 15.02.2013). Method and device for long term variability monitoring of cardiovascular parameters based on registered electrocardiograph and pulse wave signals. Application P201100016 (filed 09.03.2011). Inventors: Kalju Meigas, Mart-Rein Rosmann, Jaanus Lass, Jüri Kaik, Kristjan Pilt, Denis Karai, Indrek Raig, Avo Tölpt. Owners: Tensiotrace OÜ,Tallinn University of Technology.
7.4 Assessment of myocardial electrical instability in sleep apnea patients.
Novel algorithms for complex investigation of ECG QT interval were applied to polysomnographic recordings in order to measure myocardial electrical instability [1-4], i.e. predisposition to potentially life-threatening cardiac arrhythmias in patients with various sleep apnea degrees. Application of this method can not only be useful for sleep apnea patients’ screening in total population, but also for determination of cardiac risk.
1. Kaik, J., Pindmaa, M; Viigimäe, M; Karai, D; Pilt, K. (2014). Comparison of Different QT-interval Variability Assessment Models in Patients with Various Degree of Sleep Apnea. In: In: 12th International Dead Sea Symposium (IDSS) on Innovations in Cardiac Arrhythmias and Devices Therapy. March 3-5,2014, Tel-Aviv., p. 98.
2. Kaik, J. (2014). Sleep apnea as the main reason of sudden cardiac death at night. In: Journal of Sleep Research, (23) 1:4-4
3. Viigimae M., Karai D., Pilt K., Pindmaa M, Meigas K, Kaik J. (2015) Assessment of ventricular repolarization prolongation and inhomogeneity reflecting parametres in different sleep stages. In: : EHRA EUROPACE - CARDIOSTIM 2015, (European Heart Rhythm Association Congress ), Milan, 21-24.Jun.2015 (Accepted)
4. Viigimae M., Karai D., Pilt K., Pindmaa M, Meigas K, Kaik J. (2015) QT Interval Variability in Different Sleep Stages. In: 4th Cardiosleep International Congress, Paris, 10-11.Apr.20155
7.5 Non-invasive, simultaneous and continuous monitoring of cardiovascular parameters on the Earth and in the Space.
Development of the heart rate and cuff-less blood circulation Holter device for non-invasive, simultaneous and continuous monitoring of cardiovascular parameters on the Earth and in the Space is a cooperation project with European Space Agency and Tensiotrace Ltd (Estonia). The study results have shown that the method proposed enables beat-to-beat blood pressure (BP) estimation and detection of 24-hour ECG parameters, including a promising myocardial electrical instability indicator – QT interval variability. Till now, no commercially available cuff-less blood pressure monitoring methods exist. It is applicable during both short-term recordings at stress test as well as 24-hour measurements in everyday clinical practice. It is applicable during both short-term recordings at stress test as well as 24-hour measurements in everyday clinical practice. Properly calibrated prototype device demonstrated good and stable correlation between estimated systolic BP values and oscillometric and manual auscultatory measurements throughout the whole recording period. The method is based on good linear relationship between routinely estimated BP values and pulse arrival time (PAT) detected between the ECG R-peak and forehead photoplethysmographic pulse wave rising front. From technical side the recording quality of the prototype device turned out to be remarkably good in the feasibility study phase. Still in the following steps number of improvements have to be carried out in the device development such as: the PPG sensor enhancements for long term monitoring; the prototype miniaturization up to clinically rational dimensions; development of calibration device; and finally development of the integrated software tool that combines the processing of 24-hour ECG with additional QT and PAT interval analysis. The application interface of the software requires a design that is convenient for physicians.
Cooperation: Clinic of Cardiology and TM Cardiology Team
PhD students: Moonika Viigimäe (expected defence in 2018)
1. Shipilova, T; Pshenichnikov, I; Karay, D; Ripulk, E; Kaik, Yu. (2013). 24-Hour Heart Rate Profile in Assessment of Target Organs in Women With Arterial Hypertension. Kardiologiya, 53(1), 45 - 50.