A system and method for determining and controlling a cardiac condition of a subject are provided. In some aspects, the method includes acquiring ECG signals using one or more electrodes configured to sense a cardiac activity of a subject, and analyzing the ECG signals to delineate cardiac waveforms on a beat-to-beat basis. The method also includes identifying, in the delineated cardiac waveforms, characteristic points associated with different phases of cardiac activity, and for each delineated cardiac waveform, computing an ischemic index using the ECG signals corresponding to a ventricular depolarization period and a ventricular repolarization period, wherein the ventricular depolarization period and the ventricular repolarization period are defined by the identified characteristic points. The method further includes determining a cardiac condition of the subject using each computed ischemic index.
