Biomedical subjects

H al-Nashash

Publications and source records attributed to H al-Nashash.

4 recordsLinked to original sources

PubMed1997

Detection of life-threatening cardiac arrhythmias using the wavelet transformation.

Time-frequency wavelet theory is used for the detection of life threatening electrocardiography (ECG) arrhythmias. This is achieved through the use of the raised cosine wavelet transform (RCWT). The RCWT is found to be useful in differentiating between ventricular fibrillation, ventricular tachycardia and atrial fibrillation. Ventricular fibrillation is characterised by continuous bands in the range of 2-10 Hz; ventricular tachycardia is characterised by two distinct bands: the first band in the range of 2-5 Hz and the second in the range of 6-8 Hz; and atrial fibrillation is determined by a low frequency band in the range of 0-5 Hz. A classification algorithm is developed to classify ECG records on the basis of the computation of three parameters defined in the time-frequency plane of the wavelet transform. Furthermore, the advantage of localising and separating ECG signals from high as well as intermediate frequencies is demonstrated. The above capabilities of the wavelet technique are supported by results obtained from ECG signals obtained from normal and abnormal subjects.

Algorithms↗

PubMedDate not supplied

ECG data compression using Hebbian neural networks.

Principal component analysis has long been used for a variety of signal processing applications, including signal compression. Neural network implementations of principal component analysis provide a means for unsupervised feature discovery and dimension reduction. In this paper, we describe a method for the compression of ECG data using principal component analysis. Hebbian neural networks were used for principal components computation. A variety of examples of normal and pathological ECGs obtained from the MIT ECG database demonstrate that the proposed method can provide compression ratio up to 30 with PRD% less than 5%.

Algorithms↗

PubMedDate not supplied

ECG response of the human body subjected to vibrations.

In this paper, the ECG response of the human body subjected to vibrations is investigated. Measurements relied on recording the ECG and then computing the normalized difference of the ECG power spectrum density. Ten subjects aged 20-22 years old were exposed for 15 min to vertical vibrations in the frequency range 5-30 Hz. Results show either depression or elevation of the ST segment indicating heart muscle fatigue. The power spectrum density normalized difference also shows that the maximum difference takes place at 8 Hz vibrations frequency which is thought to be around the resonance frequency of the heart.

Adult↗

PubMedDate not supplied

Effect of vibrations with two different amplitudes on the ECG.

The ECG response of a human body exposed to vertical vibrations was investigated. The per cent normalized difference (PND) between the R-wave amplitude before and after vibrations was monitored. Results obtained from a representative subject show an oscillatory decay of the PND behaviour with time. This behaviour can be modelled as a linear second order damped system. The natural frequency, damping ratio and the recovery time of the cardiac system can be measured.

Adult↗