The computerized patient monitoring system developed in conjunction with Surgery Branch, NHLBI, provides realtime, beat-to-beat analysis of physiologic waveforms from patients within a four-bed intensive care unit. Based around a Xerox Sigma-3 Computer, the system monitors the electrocardiogram, arterial and venous blood pressurs, body temperature, urine output, and blood loss, as well as thermal and dye-dilution cardiac output. A Morphology Analsis of the electrocardiogram and arterial blood pressure waveforms is performed to detect fiducial markers. The application of cross-correlation techniques to the electrocardiogram allows the detection of premature ventricular contractions. Beat-to-beat data from the most recent thousand electrocardiographic complexes may be recalled at any time in the form of Joint Interval Histograms and Correlation Coefficient Scatter Diagrams. A five-minute electrocardiogram memory is maintained in realtime for use in the detection of transient ventricular arrhythmias. Vital signs are retrievable as eight-hour nursing shift summaries in tabular form, or as 12-, or 72-hour vital signs graphs.