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The aim of the study is to evaluate the influence of diabetes mellitus (DM) on T-wave and QRS-complex alternans (TWA&QRSA) during stress ECG testing. Principal component analysis, combined with wave amplitude computation was used for TWA&QRSA quantification. We studied 77 patients (64±1 1 years, 44% male). DM was present in 43% and angiographically significant coronary artery disease (AS_CAD)...
There are evidences suggesting that spaceflight may be associated with increased susceptibility to ventricular dysrhythmias. To explore this hypothesis, five days −6° head-down bed rest (HDBR) was performed with the aim at testing the changes in QT/RR dynamics. Electrocardiogram signals (ECG) was acquired in 22 males during tilt-tests performed before and after HDBR. The dynamics of QT interval adaptation...
Myocardial scar is the most common substrate for malignant arrhythmia and cardiac arrest. Radiofrequency ablation, as one of the emerging mainstream therapies, currently relies on electrophysiologic (EP) map acquired on endocardial and occasionally epicardial surfaces. As myocardial scar is often complex with shapes varying with the depth of the myocardium, endocardial and epicardial maps may differ...
Arrhythmic death is the leading cause of mortality among End-Stage Renal Disease patients but determining which of these patients are at sufficient risk to warrant defibrillator therapy remains an open question. To test whether ECG parameters reflecting ventricular repolarization could help risk stratify these patients, we performed a prospective observational study involving 50 chronic hemodialysis...
ECG telemonitoring is a relatively new advancement of medical technology which enables distant control of the health status. There is a great research progress in recording, wireless transfer and automatic analysis of ECG signals, but clinical experience with working ECG telemonitoring systems is very limited. We evaluated 60 patients, applying simultaneously standard Holter ECG and a heart rhythm...
Modern QRS detectors in patient monitoring systems must provide accurate results even when interfering noise is present. This task is complicated by the heterogeneous and non-uniform nature of the patient population. Certain beat morphologies demand a significant increase in the complexity of beat detection algorithms. At the same time, it is important to take a system-wide approach to the beat detection...
Congenital heart disease is the most common cause of death in infants. Three-dimensional echocardiography may provide reliable information than two-dimensional methods. The purpose of the study was attempted to evaluate the feasibility and accuracy of the 3D echocardiographic virtual endoscopy in Atrial Septal Defect (ASD). An improved fuzzy C-means clustering algorithm brFCM was adopted to accelerate...
The aim of our study was to apply two HRV methods (PD2i and wavelet-CART) for the individual forecasting of ventricular tachycardia (VT) and death in telemedicine setting during the cardiac rehabilitation of postinfarction patients. Eighty-eight postinfarction patients were ECG monitored monthly during 36 months. The predictive accuracy of time-frequency HRV variables for ventricular tachycardia (VT),...
Heartbeat dynamics is a complex system. To characterize it properly, advanced nonlinear signal-processing methods are needed. In this context, recent developments on reconstructible signals and multiscale information content have led to the Microcanonical Multifractal Formalism (MMF). The MMF provides signal-analysis techniques particularly suited to heartbeat dynamics. In particular, electrocardiogram...
Baseline wander always exists along with ECG signal. It is a kind of noise and may interference the diagnosis of cardio diseases, especially for the automatic diagnosis. Most methods could eliminate baseline wander already, however be difficult to meet the requisition of low distortion. To solve this problem, a morphology algorithm based on 2-D flat structure element is proposed, where flat structure...
We present an algorithm for assessing the ECG signal quality in real time. The algorithm is designed for small systems with low computational power. The method estimates the ECG cepstrum on a running window of 10 s and calculates the power of the highest peak in the “quefrency” band of the mean cardiac interval (between 0.25 and 2.0 s). If the ECG is corrupted by noise, the power of this cepstral...
The performance of PCA and ICA in the context of cleaning noisy ECGs in ambulatory conditions was investigated. With this aim, ECGs with artificial motion artifacts were generated by combining clean 8-channel ECGs with 8-channel noise signals at SNR values ranging from 10 down to −10 dB. For each SNR, 600 different simulated ECGs of 10-second length were selected. 8-channel PCA and ICA were applied...
In this paper we have used the most useful processing and analysis methods to classify two congenital heart defects. The most important congenital valve disease is the congenital aort stenosis(AS) and of septum diseases is Ventricular Septal Defect(VSD). In this research, we managed to fuzzy classification of three groups of healthy, and AS, and VSD patients with the use of PCG.
Despite the important role of electro-mechanical alternans in cardiac arrhythmogenesis, its molecular origin is not well understood. In this paper we want to study alternans that can be associated with alternations in the cytosolic calcium transient. To this end we study particularly, how a malfunction of Ryanodine Receptor (RyR) recovery time from inactivation may induce beat-to-beat alternations...
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