Systems and methods are provided to detect subwaveforms of an ECG waveform. Electrical impulses are detected between at least one pair of electrodes of two or more electrodes placed proximate to a beating heart and are converted to an ECG waveform for each heartbeat of the beating heart using the detector. One or more subwaveforms within P, Q, R, S, T, U, and J waveforms of the ECG waveform for each heartbeat or in an interval between the P, Q, R, S, T, U, and J waveforms that represent the depolarization or repolarization of an anatomically distinct portion of muscle tissue of the beating heart are detected using a signal processor. A processed ECG waveform that includes the one or more subwaveforms for each heartbeat is produced using the signal processor. The processed ECG waveform is received from the signal processor is displayed using a display device.
