-
IEEE Journal of Biomedical and Health... Aug 2022Benefiting from non-invasive sensing tech- nologies, heartbeat detection from ballistocardiogram (BCG) signals is of great significance for home-care applications, such...
Benefiting from non-invasive sensing tech- nologies, heartbeat detection from ballistocardiogram (BCG) signals is of great significance for home-care applications, such as risk prediction of cardiovascular disease (CVD) and sleep staging, etc. In this paper, we propose an effective deep learning model for automatic heartbeat detection from BCG signals based on UNet and bidirectional long short-term memory (Bi-LSTM). The developed deep learning model provides an effective solution to the existing challenges in BCG-aided heartbeat detection, especially for BCG in low signal-to-noise ratio, in which the waveforms in BCG signals are irregular due to measured postures, rhythm and artifact motion. For validations, performance of the proposed detection is evaluated by BCG recordings from 43 subjects with different measured postures and heart rate ranges. The accuracy of the detected heartbeat intervals measured in different postures and signal qualities, in comparison with the R-R interval of ECG, is promising in terms of mean absolute error and mean relative error, respectively, which is superior to the state-of-the-art methods. Numerical results demonstrate that the proposed UNet-BiLSTM model performs robust to noise and perturbations (e.g. respiratory effort and artifact motion) in BCG signals, and provides a reliable solution to long term heart rate monitoring.
Topics: Algorithms; BCG Vaccine; Ballistocardiography; Heart Rate; Humans; Memory, Short-Term
PubMed: 35333727
DOI: 10.1109/JBHI.2022.3162396 -
Harvard Heart Letter : From Harvard... Jul 2012
Ask the doctors. I recently developed atrial fibrillation, and I wonder whether I need to take an anticoagulant. I am 81 years old, active, and don't really notice when I am in atrial fibrillation. I was taking my pulse every now and then and found it to be irregular. My doctor said I was going...
Topics: Anticoagulants; Atrial Fibrillation; Heart Rate; Humans; Hypertension; Warfarin
PubMed: 27024434
DOI: No ID Found -
Clinical Autonomic Research : Official... Apr 2016Spinal cord injury (SCI) is commonly associated with devastating paralysis. This condition also results in cardiovascular autonomic dysfunction associated with increased...
INTRODUCTION
Spinal cord injury (SCI) is commonly associated with devastating paralysis. This condition also results in cardiovascular autonomic dysfunction associated with increased mortality from cardiovascular disease. The purpose of this study was to explore the differences in cardiovascular autonomic modulation in individuals with and without SCI.
METHODS
The study included 60 individuals: 30 individuals without SCI, who formed the control group-CG and 30 individuals with SCI, who formed the SCI group-SCIG. The latter group was divided into two, one group of subjects with SCI above the spinal segment T6-SCIG (above T6) and a group of individuals with SCI below T6-SCIG (below T6). The subjects were evaluated by linear and nonlinear analysis of heart rate variability (HRV).
RESULTS
The SCIG showed significantly lower square root of the mean squares differences of successive NN intervals (rMSSD), number of pairs of adjacent NN intervals differing by more than 50 ms (pNN50), standard deviation of short-term HRV (SD1), and high frequency power (HF). Their low frequency power (LF) in absolute units (ms(2)) was significantly lower and their normalized units (n.u.) were significantly higher. Their LF/HF ratio was significantly higher, and sample entropy (SampEn), which indicates the complexity and irregularity of the NN intervals time series, was significantly lower compared to the CG. The differences between the SCIG and CG were derived mainly from the SCIG (above T6). The correlation test revealed very low values between each of the parameters evaluated for CG and SCIG.
CONCLUSIONS
The SCIG (above T6) showed greater cardiovascular autonomic impairment compared to SCIG (below T6) and CG. The SCIG (below T6) also presented some degree of autonomic dysfunction. All parameters, linear or nonlinear, are suitable to demonstrate the differences between the SCIG and CG.
Topics: Adult; Autonomic Nervous System; Autonomic Nervous System Diseases; Cardiovascular System; Cross-Sectional Studies; Electrocardiography; Female; Heart Rate; Humans; Male; Paraplegia; Quadriplegia; Spinal Cord Injuries
PubMed: 26951134
DOI: 10.1007/s10286-015-0339-1 -
Psychosomatic Medicine 1999This study examined the effects of "tanden breathing" by Zen practitioners on cardiac variability. Tanden breathing involves slow breathing into the lower abdomen. (Comparative Study)
Comparative Study
OBJECTIVE
This study examined the effects of "tanden breathing" by Zen practitioners on cardiac variability. Tanden breathing involves slow breathing into the lower abdomen.
METHODS
Eleven Zen practitioners, six Rinzai and five Soto, were each studied during 20 minutes of tanden breathing, preceded and followed by 5-minute periods of quiet sitting. During this time, we measured heart rate and respiration rate.
RESULTS
For most subjects, respiration rates fell to within the frequency range of 0.05 to 0.15 Hz during tanden breathing. Heart rate variability significantly increased within this low-frequency range but decreased in the high-frequency range (0.14-0.4 Hz), reflecting a shift of respiratory sinus arrhythmia from high-frequency to slower waves. Rinzai practitioners breathed at a slower rate and showed a higher amplitude of low-frequency heart rate waves than observed among Soto Zen participants. One Rinzai master breathed approximately once per minute and showed an increase in very-low-frequency waves (<0.05 Hz). Total amplitude of heart rate oscillations (across frequency spectra) also increased. More experienced Zen practitioners had frequent heart rhythm irregularities during and after the nadir of heart rate oscillations (ie, during inhalation).
CONCLUSIONS
These data are consistent with the theory that increased oscillation amplitude during slow breathing is caused by resonance between cardiac variability caused by respiration and that produced by physiological processes underlying slower rhythms. The rhythm irregularities during inhalation may be related to inhibition of vagal modulation during the cardioacceleratory phase. It is not known whether they reflect cardiopathology.
Topics: Adult; Analysis of Variance; Arrhythmia, Sinus; Baroreflex; Breathing Exercises; Buddhism; Female; Heart Rate; Humans; Japan; Male; Practice, Psychological; Psychophysiology; Respiration
PubMed: 10593633
DOI: 10.1097/00006842-199911000-00014 -
IEEE Transactions on Bio-medical... Oct 2020The neck is a very attractive measurement location for multimodal physiological monitoring, since it offers the possibility of extracting clinically relevant parameters,...
OBJECTIVE
The neck is a very attractive measurement location for multimodal physiological monitoring, since it offers the possibility of extracting clinically relevant parameters, which cannot be obtained from other body locations, such as lung volumes. It is for this reason that obtaining PPG from the neck would be of interest. PPG signals, however, are very susceptible to artifacts which greatly compromise their quality. But the extent of this is going to depend on, the nature of the artifacts and the strength of the sensed signal, both of which are location dependent. This paper presents for the first time the characterization of artifacts affecting neck PPG signals.
METHODS
Neck PPG data was recorded from 19 participants, who performed ten different activities to deliberately introduce common artifacts. 41 PPG features were extracted and statistically analyzed to investigate which ones showed the greatest ability to differentiate normal PPG from each artifact. A customized minimum Redundancy Maximum Relevance (mRMR) feature selection approach was implemented, to select the top 10 features.
RESULTS
Artifacts caused by Swallowing, Yawning and Coughing exhibited larger Spectral Entropy, Average Power and smaller Spectral Kurtosis, than normal PPG. Head movement artifacts, also demonstrated highly disordered and noisy frequency spectra, and were characterized by having larger and irregular time domain features. In addition, the analysis showed that different respiratory states that could be of clinical interests, such as presence of apneas, were also distinguishable from sources of interference.
SIGNIFICANCE
These findings are important for the development of PPG denoising algorithms and subsequent obtention of biomarkers of interest, or alternatively for applications where the events of interest are the artifacts themselves.
Topics: Algorithms; Artifacts; Head Movements; Heart Rate; Humans; Monitoring, Physiologic; Photoplethysmography; Signal Processing, Computer-Assisted
PubMed: 32142413
DOI: 10.1109/TBME.2020.2972378 -
International Journal For Numerical... Jun 2022The computational cost of a three-dimensional (3D) fluid-structure interaction (FSI) simulation of a dissected aorta has prevented researchers from investigating the...
The computational cost of a three-dimensional (3D) fluid-structure interaction (FSI) simulation of a dissected aorta has prevented researchers from investigating the effect of a wide range of the heart rate on the hemodynamic quantities in the disease. We have presented a systematic procedure to develop a zero-dimensional (0D) model for a dissected aorta. A series of numerical experiments were used to calculate the values for the resistance, inertance, and compliance of each lumen with irregular geometries. Having validated the results from the 0D model against those from the 3D model for one heart rate, we used the 0D model to investigate the effect of the heart rate of 50-150 bpm on the flow rates and the pressures in an idealized geometry of an aortic dissection. The 0D model showed acceptable accuracy when compared with the 3D FSI simulation. For instance, at peak systole, 7.18% relative error in the flow rate in the true lumen was observed for 0D and 3D simulations. The flow rate in the true lumen showed a stronger dependency on the heart rate, that is, 300% for the true lumen and 1.5% for the false lumen. The pressure difference between the lumina increased non-monotonically as the heart beats faster. Because of its efficiency, the reported procedure can be used for uncertainty and sensitivity analysis of the hemodynamic quantities in a diseased aorta with complex geometries such as that of the aortic dissection.
Topics: Aortic Dissection; Aorta; Heart Rate; Hemodynamics; Humans; Models, Cardiovascular
PubMed: 35338602
DOI: 10.1002/cnm.3596 -
Journal of Hypertension. Supplement :... Dec 1999Diastolic blood pressure (DBP) has historically functioned as the primary indicator of cardiovascular disease (CVD). Many clinical and observational, long-term, large... (Review)
Review
Diastolic blood pressure (DBP) has historically functioned as the primary indicator of cardiovascular disease (CVD). Many clinical and observational, long-term, large population studies, including the Framingham Heart Study and Multiple Risk Factor Intervention Trial (MRFIT), have repeatedly demonstrated a positive correlation between CVD events and DBP. However, unexplained results, often emerged from the data, in the form of a DBP threshold (where lower rates of DBP were not associated with lower disease rates) and a J-shaped relationship (a decline of DBP that correlated with an increased risk of CVD), have complicated the association of blood pressure to events. In the past decade studies have focused on other indicators to explain these irregularities. From these clinical and observational studies, new evidence has become available which strongly indicates that systolic blood pressure (SBP) and pulse pressure (PP) may be more reliable predictors of CVD events than DBP. Indeed, in several studies, a wide baseline PP has been identified as the only measure of blood pressure that is an independent risk factor for cardiac events. Moreover, pretreatment SBP has linearly predicted future CVD events in treated patients, while DBP has not. These studies of treated patients have also led to the identification of pretreatment risk factors that can be applied to stratify risk among patients who go on to have controlled blood pressure on treatment. This new information can more precisely identify patients at increased risk of CVD events and thus make it possible to more precisely tailor therapy to enhance the potential for CVD prevention.
Topics: Blood Pressure; Blood Pressure Determination; Cardiovascular Diseases; Disease Progression; Humans; Prognosis; Pulse; Risk Assessment; Risk Factors
PubMed: 10706322
DOI: No ID Found -
Archives of Neurology Nov 1989The occurrence of high-risk cardiac arrhythmias during electrographic seizures has been proposed as a possible cause for sudden unexpected death in patients with...
The occurrence of high-risk cardiac arrhythmias during electrographic seizures has been proposed as a possible cause for sudden unexpected death in patients with epilepsy. Several anecdotal case reports have documented various cardiac irregularities during seizures. We reviewed simultaneous 24-hour electroencephalographic - electrocardiographic studies obtained by ambulatory cassette electroencephalography in 45 patients who experienced 106 electrographic seizures. An increase in heart rate was seen in 96% of seizures, while in four seizures, the rate was unchanged. Heart rate increase measured from 1 minute preictally to intraictal peak ranged from 0% to 160% (mean, 60%). The onset of tachycardia was usually within several seconds (before or after) of the seizure onset, and often persisted for several minutes after termination of the discharge. No difference was found in patients with lateralized vs generalized seizures. Neither ventricular ectopia, conduction defects, or bradycardia were observed during the ictal episodes. We conclude that ictal tachycardia is the rule during electrographic seizures, and that high-risk cardiac arrhythmias are uncommon.
Topics: Adolescent; Adult; Aged; Arrhythmias, Cardiac; Child; Child, Preschool; Electrocardiography; Heart Rate; Humans; Middle Aged; Seizures
PubMed: 2818251
DOI: 10.1001/archneur.1989.00520470023018 -
Computer Methods and Programs in... Sep 2021Atrial fibrillation (AF) is the most common cardiac arrhythmia in the world. It is associated with significantly increased morbidity and mortality. Diagnosis of the...
BACKGROUND AND OBJECTIVE
Atrial fibrillation (AF) is the most common cardiac arrhythmia in the world. It is associated with significantly increased morbidity and mortality. Diagnosis of the disease can be based on the analysis of the electrical atrial activity, on quantification of the heart rate irregularity or on a mixture of the both approaches. Since the amplitude of the atrial waves is small, their analysis can lead to false results. On the other hand, the heart rate based analysis usually leads to many unnecessary warnings. Therefore, our goal is to develop a new method for effective AF detection based on the analysis of the electrical atrial waves.
METHODS
The proposed method employs the fact that there is a lack of repeatable P waves preceding QRS complexes during AF. We apply the operation of spatio-temporal filtering (STF) to magnify and detect the prominent spatio-temporal patterns (STP) within the P waves in multi-channel ECG recordings. Later we measure their distances (PQ) to the succeeding QRS complexes, and we estimate dispersion of the obtained PQ series. For signals with normal sinus rhythm, this dispersion is usually very low, and contrary, for AF it is much raised. This allows for effective discrimination of this cardiologic disorder.
RESULTS
Tested on an ECG database consisting of AF cases, normal rhythm cases and cases with normal rhythm restored by the use of cardioversion, the method proposed allowed for AF detection with the accuracy of 98.75% on the basis of both 8-channel and 2-channel signals of 12 s length. When the signals length was decreased to 6 s, the accuracy varied in the range of 95%-97.5% depending on the number of channels and the dispersion measure applied.
CONCLUSIONS
Our approach allows for high accuracy of atrial fibrillation detection using the analysis of electrical atrial activity. The method can be applied to an early detection of the desease and can advantageously be used to decrease the number of false warnings in systems based on the analysis of the heart rate.
Topics: Atrial Fibrillation; Electrocardiography; Heart Atria; Heart Rate; Humans
PubMed: 34091101
DOI: 10.1016/j.cmpb.2021.106167 -
Hospital Practice (Office Ed.) Nov 1983
Topics: Arrhythmias, Cardiac; Electrocardiography; Female; Heart Rate; Humans; Middle Aged; Psoriasis; Pulse
PubMed: 6414930
DOI: 10.1080/21548331.1983.11702689