Study of cardiac arrhythmia using the Kalman filter.

It has been known for some time that the variability of the R-R intervals in the electrocardiogram signal yields valuable information concerning the various types of arrhythmia that might be present. It has recently been suggested that the identification of cardiac arrhythmia might be possible by applying spectral analysis techniques to the data. An investigation is made into the possible application of the Kalman filter identifier in the calculation of time varying spectra of the data, with a view to studying the onset of arrhythmia and also short bursts of arrhythmia. To this end, data from the MIT-BIH database are analysed; in particular, cases of bigenimy, trigenimy, second degree block and ventricular flutter have been looked at. It is found that this technique can, in many cases, detect the onset of arrhythmia and sometimes actually identify the arrhythmia that is present. It is suggested that the Kalman filter identifier could have a general application in studying both the normal and arrhythmic segments of data to yield valuable medical information concerning the subject under study.