An Arrhythmia-Anomalous Beat Monitoring System

An electronic monitoring system has been developed to detect the four conditions that usually lead to fibrillation in the infarcted heart. Artifact-free QRS detection is accomplished by passing the preamplified QRS through a bandpass filter, an automatic gain control (AGC)circuit, a full-wave rectifier, a nonlinear amplifier, and positive and negative slope detectors. High-threshold logic circuitry then applies the timing criteria necessary for positive identification of a QRS complex. A printout of the ECG is made if 1) the number of premature beats in the last minute exceeds a physician-set number (0 through 10), 2) the number of successive anomalous beats (i. e., area increase, QRS increase, or polarity reversal) exceeds a physician-set number (0 through 5), 3) an "early" premature beat occurs (i.e., R-R' < QT), or 4) a multiformal beat is detected (i.e., its morphology differs from that of the previous anomalous beat).