[Computer compatible long-term ECG analysing system for quantitative detection of low grade and complex...

On the basis of a commercially available analyser2) a long-term ECG analysing system for quantitative detection of the following events was developed: all QRS complexes, ventricular premature beats (VPB), VPB with different coupling intervals (including the R/T phenomenon), paired VPB, salvos of VPB, ventricular tachycardias, ventricular bigeminy, supraventricular premature beats, supraventricular tachycardias, and asystoles. These dysrhythmias are detected simultaneously at 60-fold speed and counted within predeterminable time intervals, the results being printed out and at the same time stored on punch tape, thus allowing off-line computer processing of the data. The accuracy of the analysing system working in a fully automatic mode was evaluated by comparison to the results obtained by two cardiologists. The predictive value of the analyser was 99.9% for all QRS complexes and 97.2% for aberrantly shaped QRS complexes. The corresponding values of the sensitivity were 99.7% and 95.3%. For paired VPB or salvos of VPB and ventricular bigeminy the predictive value was 91.8% and 95.1%, respectively, the sensitivity being 93.4% and 87.9%, respectively. For the detection of asystoles, in spite of a 100% sensitivity a predictive value of only 45.6% was found. Therefore these events may well be detected automatically, but the false positive counts will have to be sorted out by visual inspection on the oscilloscope or ECG write-out.