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This study aims at characterizing the short-term time-courses of time- and frequency-domain heart rate variability (HRV) parameters during head-up tilt test (HUTT). Data from 44 young patients with a history of syncope and 34 age-matched controls was analysed in two age-groups related to puberty (<13 and >14 years), and separately for gender, by extracting minute-by-minute progression of mean...
Laplacian Electrocardiogram (LECG) is a non-invasive approach providing high spatiotemporal distributed information of cardiac electrical activity. Recently researchers have recorded surface potentials from monopolar disc electrodes to estimate the Laplacian using finite difference algorithms or spline surface Laplacian estimators. Bipolar and quasi-bipolar electrodes have also been used to record...
Atrial fibrillation (AF) and flutter are common following cardiac surgery, increasing costs and morbidity. Cardiologists need a method to discern those patients who are at high risk for this arrhythmia in order to attempt to treat them by either pharmacologic or non-pharmacologic means. We performed a retrospective analysis of 377 CABG patients, of which 94 developed AF post-operatively. Feature selection...
Long hours of automobile driving under monotonous situations may cause the lowering of what we term a driver's activation state (DAS) or in other words the production of drowsiness, resulting in an increased risk of a traffic accident. There is therefore a need to create a newly advanced system focused on the DAS in-car, hopefully thus avoiding potentially dangerous situations. In order to develop...
For customizing the assistance scheme of a torque-assisted bicycle, we estimated physical activity during cycling with ECG and surface EMG for the circuit including a steep uphill section near the middle and compared it with the vehicle data. Using the respiratory-sinus-arrhythmia-related power ratio in the fluctuation of the R-R interval, prRSA and a muscular fatigue index, we classified physical...
In this study, we discuss the use of support vector machine (SVM) learning to classify heart rate signals. Each signal is represented by an attribute vector containing a set of statistical measures for the respective signal. At first, the SVM classifier is trained by data (attribute vectors) with known ground truth. Then, the classifier learnt parameters can be used for the categorization of new signals...
This paper presents results of blood pressure dynamicity analysis aimed at vessel stiffness detection and subsequent cardiac risk stratification. We analyzed ECG and BP parameters from 12 normotensive young healthy volunteers, 10 old healthy volunteers, and two groups of hypertensive patients-12 young non-medicated hypertensive subjects with no other known complications and 16 hypertensive non-medicated...
A Hidden Markov Model (HMM) is used to improve the robustness to noise when tracking the atrial fibrillation (AF) frequency in the ECG. Each frequency interval corresponds to a state in the HMM. Following QRST cancellation, a sequence of observed states is obtained from the residual ECG, using the short time Fourier transform. Based on the observed state sequence, the Viterbi algorithm, which uses...
A new system has been developed for obtaining electrographic potential through thin underwear inserted between the measuring electrodes and the skin of a neonate or an infant when lying supine. The system is based on capacitive coupling involving the electrode, the underwear, and the skin. Validation of the system revealed the following: (1) the signal detected using the system displayed a periodic...
To study calcium mediated arrhythmogenesis, we have developed a multi-modal optical mapping system that is able to perform dual calcium voltage and ratiometric calcium optical mapping in the same cardiac preparation. To ensure physiological stability of the preparation, the ECG, coronary pressure, coronary flow, and perfusion temperature are continuously monitored throughout each experiment. The multi-modal...
High cost of diagnostic studies to detect sleep disordered breathing and lack of availability of certified sleep laboratories in all inhabited areas make investigation of alternative methods of detecting sleep disordered breathing attractive. This study aimed to explore the possibility of discerning obstructive sleep apnea (OSA) from Cheyne-Stokes respiration (CSR) using overnight electrocardiography...
Continuous and non-invasive monitoring of blood pressure (BP) is important to prevent hypertensive patients from stroke and heart attack. However, most of the prevalent BP devices can provide solely intermittent measurements. In this study, a novel parameter RS2 , defined as the time interval from the R wave of electrocardiographic (ECG) signal to the peak of second heart sound of phonocardiographic...
Pulse arrival time and the amplitude of the finger photoplethysmogram were used to track blood pressure continuously over 10-minute intervals. The measures were recorded with a holter-oximeter from a sample of 8 young, healthy human subjects in the supine and standing positions. Results indicate that, with individual calibration, systolic and diastolic blood pressure can be estimated with an average...
The heart rate is a basic health indicator, useful in both clinical measurements and home health care. Current home care systems often require the attachment of electrodes or other sensors to the body, which can be cumbersome to the patient. Moreover, some measurements are sensitive to movement artifacts, are not user-friendly and require a specialized supervision. In this paper, a novel technique...
The purpose of this work is to characterize the heart rate variability (HRV) of patients affected by congestive heart failure (CHF) and to find out the main difference between this pathological condition and the physiological state. Parameters adopted in this work are: the detrended fluctuation analysis (DFA) and the Higuchi exponent to assess long correlations and self-similarity; the regularity...
This paper presents a method of automatic processing the electrocardiogram (ECG) signal for the classification of heart beats. Data were obtained from 48 records of the MIT-BIH arrhythmia database (only one lead). Five types of arrhythmic beats were classified using our method, Premature Ventricular Conduction beat (PVC), Atrial Premature Conduction beat (APC), Right Bundle Branch Block beat (RBBB),...
Reconstruction of the epicardial potentials from the body surface potentials constitutes one form of the ill-posed inverse problem of electrocardiography (ECG). In this paper, we investigate the use of genetic algorithms (GAS) for regularizing ill-posed ECG inverse problem. The result shows that, GAS cannot be used to regularized ill-posed problem without additional constraints, but combined with...
Calculating the potentials on the heart's epicardial surface from the body surface potentials constitutes one form of inverse problems in electrocardiography (ECG). Since these problems are ill-posed, one approach is to use zero-order Tikhonov regularization, where the squared norms of both the residual and the solution are minimized, with a relative weight determined by the regularization parameter...
This paper presents the results of morphological heart arrhythmia detection based on features of electrocardiography, ECG, signal. These signals are obtained from MIT/BIH arrhythmia database. The ECG beats were first modeled using Hermitian basis functions, (HBF). In this step, the width parameter, sigma, of HBF was optimized to minimize the model error. Then, the feature vector which consists of...
The purpose of this study, was to asses whether LF/(LF+HF) obtained from ventricular repolarization variability (VRV) reflects the state of sympathovagal balance. The VRV time series and heart rate variability (HRV) time series from seventy two electrocardiogram (ECG) records in four different autonomic nervous system (ANS) profiles (athletes, cardiac transplant patient, heart failure patients and...
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