A novel and simple technique to allow detection of the position of the R-waves from intraventricular pressure waveforms: application to the conductance catheter method
| Autor: | M.E. Lewis, J.H. Coote, A. H. Al-Khalidi, J.N. Townened, R.S. Bonser |
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| Rok vydání: | 2001 |
| Předmět: |
Male
Signal processing Swine Systole Biomedical Engineering Butterworth filter Signal Processing Computer-Assisted Filter (signal processing) Ventricular Function Left Electrocardiography Noise Signal-to-noise ratio Calibration Electronic engineering Animals Waveform Female Infinite impulse response Digital filter Mathematics Biomedical engineering |
| Zdroj: | IEEE Transactions on Biomedical Engineering. 48:606-610 |
| ISSN: | 0018-9294 |
| DOI: | 10.1109/10.918602 |
| Popis: | A simple and novel technique that utilizes the zero-crossing points of the first time derivative of intra-ventricular pressure (dP/dt) to mark systole, is proposed. Discrete differentiation of the sampled pressure waveform is calculated using a difference equation. Filtration of high-frequency noise in dP/dt is achieved using a low-pass Butterworth filter of order 4 and a cutoff frequency of 10 Hz. The filter is realized digitally using infinite impulse response filter stages. Double filtering of discrete dP/dt is used to eliminate time shifts. The methods are evaluated on data obtained from six large, white, anaesthetised and open chest pigs, instrumented with a conductance catheter. The zero-crossing points of the filtered dP/dt compare very well with the R-waves of the electrocardiogram (ECG) as markers of systole. The mean error is 1.3% of the duration of the heartcycle. Significantly, our results provide a solution to a problem often encountered with multiuse pressure-volume catheters when an ECG signal cannot be obtained. In this situation, the zero-crossing points of dP/dt, rather than the R-waves of the ECG, can be used as a marker of systole, thus enabling the construction of end-systolic pressure-volume relations to assess cardiac contractility. |
| Databáze: | OpenAIRE |
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