An algorithm for the identification and quantification of multiform PVCs (Premature Ventricular Contractions) using a combination of time-domain and frequency-domain analysis has been developed. Initially, PVCs are grouped together on the basis of three morphological ″feature″ measurements. Because variations in signal amplitude and electrical projection of the heart can cause substantial variations in time-domain feature measurements, more than one cluster per PVC form may be generated. Redundant clusters are coalesced using three frequency-domain parameters computed on representatives from each cluster. The three frequency-domain parameters - first spectral moment of the amplitude spectrum, 5 Hz phase angle, and 10 Hz phase angle - successfully consolidate most nonunique time-domain clusters.