This document presents a system for managing treatment for an emergency cardiac event. The system includes memory, one or more electronic ports for receiving ECG signals, and a treatment module executable on one or more processing devices. The module is configured to generate transform values for a time segment of ECG, obtain one or more previous values derived from one or more earlier time segments of the ECG, and determine, based on the generated transform values, and the one or more previous values, at least one of: a) a future therapeutic action for treating the emergency cardiac event, or b) a phase of the cardiac event. The module is further configured to cause one or more output devices to present an indication of at least one of the therapeutic action or the phase of the cardiac event.