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J S Sahambi

Publications and source records attributed to J S Sahambi.

7 recordsLinked to original sources
PubMed1998

Wavelet based ST-segment analysis.

A novel algorithm for ST-segment analysis is developed using the multi-resolution wavelet approach. The system detects the QRS complexes and analyses each beat using the wavelet transform to identify the characteristic points (fiducial points). These fiducial points are, iso-electric level, the J point, and onsets and offsets of the QRS complex and T wave. The algorithm determines the T onset by looking for a point of inflection between the J point and the T peak. Furthermore, detection of characteristic points by the wavelet technique reduces the effect of noise. The results show that the proposed approach gives very accurate ST levels, as compared to the conventional (empirical) technique, at higher heart rates and with different morphologies. The algorithm detects the ST-segment length in 92.3% beats with an error of 4 ms, and in 97.3% beats the error is within 8 ms. The algorithm has been implemented on a TMS320C25 based add-on DSP card connected to a PC to provide the on-line analysis and display of ST-segment data.

Algorithms↗
PubMed1997

Quantitative analysis of errors due to power-line interference and base-line drift in detection of onsets and offsets in ECG using wavelets.

Timing characterisation of the ECG using wavelet transforms is a new technique in which multiscale analysis reduces the influence of noise. This technique issued to investigate the effect of noise and to estimate the errors involved in the detection of onsets and offsets of ECG waves. With appropriate choice of scales of analysis, the study shows that the errors involved in the measurement of QRS width in the presence of base-line wander are negligible. The 50 Hz power-line interference introduces a maximum error of 6.25% if it is greater than 50% of the signal amplitude. The P and T complexes are not affected by power-line interference, but the base-line wander introduces a maximum error of 9.6%. In situations with the simultaneous presence of both types of noise, the use of an optimised scale restricts the errors to within clinically acceptable limits.

Electricity↗
PubMed1997

Beat by beat QT interval detection and characterization.

A novel algorithm for detection and analysis of QT interval, a risk factor for sudden cardiac death, is developed using the multiresolution wavelet approach. The characteristic points for detection of QT interval, i.e., the onset and offsets of the QRS complex and the T wave are detected by analyzing the wavelet transform of the ECG at particular scales. The results of the detailed study using standard data base indicate that proposed technique can be used to monitor critical heart patients for localization of problems in the duration of ventricular activation. The algorithm has been implemented on TMS320C25 based add-on DSP card to PC to provide the beat by beat analysis and display of QT interval data.

Algorithms↗
PubMed1997

A DSP based real time system for analysis of bundle of His and late potentials using wavelet transforms.

A new system for analysis of Bundle of HIS and Late Potentials has been developed using the wavelet approach. The objective of the present research work is to develop a real-time system which does not rely on averaged data and has the capability to detect beat to beat variations in the cardiac micro-volt signals from the body surface recordings. Multiresolution wavelet analysis gives better time and frequency resolution of the signal and its implementation on DSP hardware makes the system real time. The clinical applicability of the system developed is currently being investigated with initial success on pre clinical data.

Bundle of His↗
PubMed1995

DSP based enhanced data acquisition system.

Digital Signal Processing (DSP) based Enhanced Data Acquisition System for Electrocardiography/Verctorcardiography (ECG/VCG) has been developed. The system is based on Texas Instrument's TMS320C25 Digital Signal Processor which has the capability of executing 5 Million Instructions Per Second (MIPS) at peak speed. This processor provides the necessary requirements of parallel processing, instruction pipelining, execution of multiple instructions in a single clock cycle for real time data acquisition and analysis of Bio Signals. The present work describes the enhanced data acquisition system using DSP chip along with its peripherals.

Biomedical Engineering↗
PubMed1992

An 8086-based Holter arrhythmia monitor.

Holter monitoring is a technique which involves the use of a specialized recorder to record and analyze the ECG of an ambulatory subject for a duration up to 24 h. It is used for persons who have generally normal ECG, but who experience heart disorders under some particular stress conditions. This paper describes the design of an 8086-based Holter monitor using state-of-the-art technology. The old concept of analog signal processing and cassette recording has been replaced by digital signal processing and solid state memories. The main features of the new monitor, as compared with conventional ones, is its intelligence to detect and record arrhythmias which are of clinical importance. Emphasis was placed on miniaturization and minimization of the power consumption while designing the monitor.

Algorithms↗