An automated analysis of electrocardiographic (ECG) waveforms, based on a precise one-dimensional analysis of features within a generalized computer-enhanced ECG waveform, has been developed in the laboratory. ECG signals are monitored, amplified, and recorded using standard techniques. The recorder output signal is distributed to a microcomputer system. Software developed for the microcomputer slows the signal playback rate and permits operator review of the slowed signal for arrhythmia analysis. The analysis program identifies and superimposes 10-40 individual ECG complexes, depending on the heart rate, and generates an 'ensembled' waveform. Operator interaction permits delineation of specific points on the displayed waveform and calculation of heart rate and duration of components within the ECG complex.