A new method for automated detection of the R-on-T phenomenon

The detection of premature ectopic beats coinciding with the T-wave of the antecedent beat is important for patient monitoring. In the method described here, the difficulties of direct measurement of QT time are avoided by evaluating the changes of QT time according to heart rate by use of a diode function generator. An analog circuit is used for comparing the computed QT time with the coupling interval of successive beats. In case of a R-on-T-phenomenon an alarm is given. The frequency of alarms is registered on a trend recorder. The methods is based on empirical equations which all contain a constant factor. Our investigations showed that the variability of this factor during longer periods of monitoring was small enough to allow sufficient exactness of the evaluation procedure.