Computer quantitated evaluation of cardiac arrhythmias

The identification of a cardiac arrhythmia depends on the interpretation of both the QRS complexes and the P waves. P wave detection is unreliable and hence automated diagnostic systems are often imperfect. An alternative is a system which detects QRS only and which classifies the QRS events; the physician then has a detailed quantitated QRS analysis to aid in diagnosis. The ATREC system has an analog QRS detector, which suppresses the P wave and the T wave frequencies and feeds a minicomputer (Mitra 15/35) with signals for the RR interval, the QRS duration, and polarity. The computer classifies these signals as either narrow or wide complexes. The narrow complexes are analyzed for irregular rhythm, bradycardia, pauses, transient or continuous tachycardia, and fibrillation. The wide complexes are classed by their coupling interval, bi- or trigeminy, doublets, or salvos, and the number per hour. The system gives a trend of the 16 beat mean, and the minimum and maximum heart rate. The data is presented on several displays.