A system for processing electrocardiograph signals includes an interface and a processor. The interface provides a first electrocardiograph signal and a second electrocardiograph signal from an electrocardiograph to the processor. The processor receives the electrocardiograph signals, processes the first electrocardiograph signal to identify a feature of the signal, and processes the second electrocardiograph signal to identify energy over time (e.g., at various time instances), and identifies a first time instance of interest based on the feature.
