Abstract: The invention provides a system and method for detecting a paced rhythm in a twelve lead ECG. A high-pass filter receives a signal from an ECG lead and pacer spikes within the high-pass filtered signal are distinguished from noise by setting certain threshold limits. Subsequently, clusters of pacer spikes are detected and raw pacer spikes corresponding to each cluster are determined. A pruning process is performed to identify one pacer spike corresponding to each paced beat and raw pacer spike with largest amplitude within a cluster is retained and other pacer spikes within the cluster are eliminated. Further, potential pacer spikes in the ECG lead are determined by eliminating pacer spikes in sections with missing data or high amount of noise. Further post-processing steps are performed to declare the identification of the paced rhythm in the ECG lead.