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Method of Photoplethysmography Diagnostics of Domesticated Animals Cardiovascular Diseases
摘要： At present time the standard procedure to diagnose cardiovascular diseases (CVD) of domesticated animals (dogs) is electrocardiography (ECG) monitoring at animal clinic. Sadly, results, obtained that way, are often mistaken because of stressful state of the animal, caused by medical manipulations [1]. The usage of photoplethysmography (PPG) method can become a good substitute for CVD monitoring. Main advantages of PPG, in compare with ECG, are single probe placement (on the ear or tailset), no need of gel electrodes and capability of measuring actual CVS parameters without need of special medical training or laboratory conditions. It is one of non-invasive methods for measuring the amount of the blood volume changes inside the blood vessels, applicable for cardio activity estimation by calculating heart rate variability. In most cases, PPG monitoring devises are small, easy to place and can monitor different physiological parameters of the animal, such as heart rate, pulse wave characteristics, blood oxygen saturation, etc.
关键词： Photoplethysmography,Health monitoring systems,Cardiovascular diseases,Pulse wave,Remote diagnostics
更新于2025-09-23 15:21:21
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Non-Invasive Detection of Mechanical Alternans Utilizing Photoplethysmography
摘要： Background and Significance: Mechanical alternans (MA) is a biomarker associated with mortality and life-threatening arrhythmias in heart failure patients. Despite showing prognostic value, its use is limited by the requirement of measuring continuous blood pressure (BP), which is costly and impractical. Objective: To develop and test, for the first time, non-invasive MA surrogates based on photoplethysmography (PPG). Methods: Continuous BP and PPG were recorded during clinical procedures and tests in 35 patients. MA was induced either by ventricular pacing (Group A, N=19) or exercise (Group B, N=16). MA was categorized as sustained or intermittent if MA episodes were observed in at least 20 or between 12 to 20 consecutive beats, respectively. Eight features characterizing pulse morphology were derived from the PPG and MA surrogates were evaluated. Results: Sustained alternans was observed in 9 patients (47%) from Group A, whereas intermittent alternans was observed in 13 patients (68%) from Group A and in 10 patients (63%) from Group B. The PPG-based MA surrogate showing the highest accuracy, V’M, was based on the maximum of the first derivative of the PPG pulse. It detected both sustained and intermittent MA with 100% sensitivity and 100% specificity in Group A and intermittent MA with 100% sensitivity and 83% specificity in Group B. Furthermore, the magnitudes of MA and its PPG-based surrogate were linearly correlated (R2=0.83, p<0.001). Conclusion: MA can be accurately identified non-invasively through PPG analysis. This may have important clinical implications for risk stratification and remote monitoring.
关键词： Blood pressure (BP),cardiac alternans,photoplethysmography (PPG),hemodynamic instabilities,mechanical alternans (MA)
更新于2025-09-23 15:21:21
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Two causes of palpitations, detected by photoplethysmography on a?mobile phone
摘要： During the 6th (and most recent) Consensus Conference of the Atrial Fibrillation Network (AFNET) and the European Heart Rhythm Association (EHRA) advanced technologies as photoplethysmography (PPG) were mentioned for the detection of atrial fibrillation (AF). PPG has here a sensitivity and specificity of 97–100% and 92–94%, respectively, for the detection of AF compared with 12-lead ECG interpretation [1]. This puzzle shows us, though, that there is more to consider on a PPG than AF alone. We can observe premature extrasystoles in bigeminy in the first episode (Fig. 1). Here, panel a shows each beat followed by another beat with a short coupling interval and a lower amplitude. The tachogram (b) shows two separate lines, where the coupling interval is represented in the bottom line, and the compensatory pause in the upper line. The Poincaré plot (c) shows two separate clusters. Fig. 2 shows an episode with AF followed by sinus rhythm. Panel a initially shows an irregular faster rhythm with different amplitudes, followed by a much slower regular rhythm, the tachogram (b) shows a chaotic spread in RR intervals which stabilises afterwards when sinus rhythm is achieved, the Poincaré plot shows sinus rhythm as a condensed cluster in the middle with AF as a chaotic pattern more southwest. Afterwards, AF was also documented on Holter monitoring and the appropriate treatment was initiated. According to this recent consensus for integrating new approaches to AF management, further investigation is needed as ECG-diagnosed AF is still the preferred method to decide on further management [1, 2]. Using these new technologies enables us to track down patients’ symptoms more conveniently and over a longer period of time, and to evaluate further with ECG if needed.
关键词： palpitations,atrial fibrillation,mobile phone,photoplethysmography
更新于2025-09-23 15:21:21
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Comparison and Noise Suppression of the Transmitted and Reflected Photoplethysmography Signals
摘要： The photoplethysmography (PPG) is inevitably corrupted by many kinds of noise no matter whether its acquisition mode is transmittance or reflectance. To enhance the quality of PPG signals, many studies have made great progress in PPG denoising by adding extra sensors and developing complex algorithms. Considering the reasonable cost, compact size, and real-time and easy implementation, this study proposed a simple real-time denoising method based on double median filters which can be integrated in microcontroller of commercial or portable pulse oximeters without adding extra hardware. First, we used the boundary extension to preserve the signal boundary distortion and designed a first median filter with the time window at approximately 78 ms to eliminate the high-frequency components of the signal. Then, through the second median filter with a time window which was about 780 ms, we estimated the low-frequency components. Finally, we removed the estimated low-frequency components from the signal to obtain the denoised signal. Through comparing the multiple sets of signals under calmly sitting and slightly moving postures, the PPG signals contained noises no matter whether collected by the transmittance-mode or the reflectance-mode. To evaluate the proposed method, we conducted measured, simulated experiments and a strong noisy environment experiment. Through comparing the morphology distortions, frequency spectra, and the signal-to-noise ratios (SNRs), the results showed that the proposed method can suppress noise effectively and preserve the essential morphological features from PPG signals. As a result, the proposed method can enhance the quality of PPG signals and, thus, can contribute to the improvement of the calculation accuracy of the subsequent physiological parameters. In addition, the proposed method could be a good choice to address the real-time noise reduction of portable PPG measuring instruments.
关键词： median filters,photoplethysmography,PPG,signal-to-noise ratio,motion artifacts,denoising
更新于2025-09-23 15:21:01
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[IEEE 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Honolulu, HI, USA (2018.7.18-2018.7.21)] 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - InstaBP: Cuff-less Blood Pressure Monitoring on Smartphone using Single PPG Sensor
摘要： Cuff-less Blood Pressure (BP) monitoring has gained interest of the research community in recent years, due to its importance in continuous and non-invasive monitoring of BP for early detection of hypertension, thereby reducing mortality. Several approaches that involve photoplethysmography (PPG) and Pulse Transit Time (PTT) have been explored with promising results; however the requirement of two sensors makes them obtrusive for continuous use. Single PPG sensor approaches using machine learning have also been attempted, but there are certain deficiencies in these methods as they go for a one-size-fits-all approach. In this work, we develop an ensemble of BP prediction models based on demographic and physiological partitioning. Also, we incorporate a set of unique PPG features into our models, which results in test accuracies of 5 mmHg Mean Absolute Error (MAE) for Diastolic BP, and 6.9 mmHg MAE for Systolic BP. Given our marked improvement over ubiquitous models (18% for Diastolic BP and 11.5% for Systolic BP), this approach opens up avenues where single PPG sensor based methods can predict BP with a high degree of accuracy. This is a big step towards developing continuous BP monitoring systems, and can help in better management of cardiac health.
关键词： machine learning,Cuff-less Blood Pressure monitoring,Pulse Transit Time,photoplethysmography,demographic and physiological partitioning
更新于2025-09-23 15:21:01
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[IEEE 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Honolulu, HI, USA (2018.7.18-2018.7.21)] 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Improved Heart Rate Tracking Using Multiple Wrist-type Photoplethysmography during Physical Activities
摘要： Photoplethysmography (PPG) signals collected from wearable sensing devices during physical exercise are easily corrupted by motion artifact (MA), which poses great challenge on heart rate (HR) estimation. This paper proposes a new framework to accurately estimate HR using two leads of PPG signals in combination with accelerometer (ACC) data in the presence of MA. A moving time window is first used to segment PPG signals and ACC signals. Then, MA is attenuated by joint sparse spectrum reconstruction in each time window, where maximum spectrum frequencies of ACC are subtracted from the spectrum frequency of PPG signals. Further, HR for each cleansed PPG is estimated from the frequency with maximum amplitude in the sparse spectrum. The actual HR is determined using spectral band powers calculated from each reconstructed PPG signals. The proposed method was validated using the 2015 IEEE Signal Processing Cup dataset. The average absolute error is 1.15 beats per minutes (BPM) (standard deviation: 2.00 BPM), and the average absolute error percentage is 0.95% (standard deviation: 1.86%). The proposed method outperforms the previously reported work in terms of accuracy.
关键词： accelerometer (ACC),heart rate (HR),motion artifact (MA),joint sparse spectrum reconstruction,Photoplethysmography (PPG)
更新于2025-09-23 15:21:01
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[ACM Press the 2nd International Conference - Taipei, Taiwan (2018.08.13-2018.08.15)] Proceedings of the 2nd International Conference on E-Society, E-Education and E-Technology - ICSET 2018 - Detecting Four-Limb Blood Oxygen Saturation and Heart Rate based on Reflex Photoplethysmography
摘要： The study purpose is to construct a reflective Oxygen Saturation (SpO2) and Heart Rate (HR) four-limb detective device, improve transmission SpO2 device only to measure finger, toe and earlobe. Using Silicon Labs Si1143, Arduino Nano, self-calibrated SpO2 algorithm and mobile application software constitute a mobile reflective SpO2 and HR detective device. Static four parts and post-exercise experiment had been carried out to test our device, the result can achieve comparable performance to a clinical device with no significant difference revealed by paired t-tests. This study has applied for clinical trial permission, the schedule will improve the calibration curve and compensation factor of unverifiable body parts by blood draw comparison. Provide clinical staff for immediate local SpO2 and HR information, evaluate the effectiveness of vascular suture and hyperbaric oxygen therapy.
关键词： Photoplethysmography,Oxygen Saturation,Heart Rate,Vascular suture,Hyperbaric Oxygen Therapy,Four-Limb
更新于2025-09-23 15:21:01
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Microcirculatory Response to Photobiomodulationa??Why Some Respond and Others Do Not: A Randomized Controlled Study
摘要： Photobiomodulation (PBM), a non‐ionizing, non‐thermal irradiation, used clinically to accelerate wound healing and inhibit pain, was previously shown to increase blood flow. However, some individuals respond to PBM, but others do not. The purpose of this study was to investigate factors affecting this patient‐specific response using advanced, noninvasive methods for monitoring microcirculatory activity. In this prospective, randomized controlled trial (NCT03357523), 20 healthy non‐smoking volunteers (10:10 males:females, 30 ± 8 years old) were randomized to receive either red‐ (633 nm and 70 W/cm2) or near‐infrared light (830 nm and 55 mW/cm2) over the wrist for 5 minutes. Photoplethysmography, laser Doppler flowmetry, and thermal imaging were used to monitor palm microcirculatory blood volume, blood flow, and skin temperature, respectively, before, during, and 20 minutes after irradiation. Participants with skin temperature change ≥0.5°C from baseline were considered “responders”. Near‐infrared PBM was found to induce a 27% increase in microcirculatory flow that increased to 54% during the 20‐minute follow‐up period (P = 0.049 and P = 0.004, respectively), but red light PBM did not increase the median flow. Only 10 of 20 participants were responders by thermal imaging (i.e., ≥0.5°C from baseline), and their initial skin temperature was between 33 and 37.5°C. The non‐responders had either “hot” hands (≥37.5°C) or “cold” hands (≤33°C). In responders, the meantime to 20% increase in microcirculatory blood volume and blood flow was less than 2.5 minutes after initiation of PBM irradiation. We demonstrated that PBM induces arteriolar vasodilatation that results in both immediate and long‐lasting increased capillary flow and tissue perfusion in healthy individuals. This response was wavelength‐dependent and modified by skin temperature. These findings regarding physiological parameters associated with sensitivity or resistance to PBM provide information of direct relevance for patient‐specific therapy.
关键词： body temperature regulation,laser‐Doppler flowmetry,microcirculation,low‐level laser therapy,vasodilation,thermal imaging,photoplethysmography
更新于2025-09-23 15:19:57
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Higha??Accuracy Photoplethysmography Array Using Neara??Infrared Organic Photodiodes with Ultralow Dark Current
摘要： Reflectance oximeters based on organic photodiode (OPD) arrays offer the potential to map blood pulsation and oxygenation via photoplethysmography (PPG) over a large area and beyond the traditional sensing locations. Here, an organic reflectance PPG array based on 16 × 16 OPD pixels is developed. The individual pixels exhibit near-infrared sensitivity up to ≈950 nm and low dark current density in the order of 10?6 mA cm?2. This results in high-quality PPG signals. Analysis of the full PPG waveform yields insight on the artery stiffness and the quality of blood circulation, demonstrating the potential of these arrays beyond pulse oximetry and heart-rate calculation.
关键词： photoplethysmography,organic photodiodes,bulk heterojunction,heartbeat,pulse oximetry
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Analytical Assessment of the Modulation Depth of Photoplethysmographic Signal Based on the Modified Beer-Lambert Law
摘要： The model for estimation of the amplitude modulation depth of photoplethysmographic (PPG) signal based on the modified Beer-Lambert law was developed. It was analytically confirmed that the modulation depth of PPG signal depends on the wavelength and illumination geometry. The modulation depth is directly proportional to the distance between the light source and the detector. The sensitivity of green light (525 nm) to blood volume changes is approximately 6-9 times greater than that for red (640 nm) and IR (805 nm) light. It was found that in case of green light, the main contribution to the modulation of PPG signal is made by absorption coefficient changes while in case of red and IR light, the modulation is mainly caused by scattering coefficient changes.
关键词： blood volume,modulation depth,photoplethysmography,amplitude modulation,modified Beer-Lambert law
更新于2025-09-23 15:19:57