Systems and methods are provided in the disclosure for estimating a risk of arrhythmia in a patient using electrocardiographic analysis. In certain aspects, a method of estimating a risk of arrhythmia in a patient is provided. The method comprises receiving electrocardiographic signals of the patient from a plurality of leads over a plurality of heart beats, averaging the electrocardiographic signals to produce an averaged electrocardiographic signal, and determining deflections in the averaged electrocardiographic signal, wherein each deflection has an amplitude and a duration. The method further comprises determining a significance of each deflection based on whether the amplitude of that deflection exceeds a threshold, and estimating a risk of arrhythmia in the patient based on at least one of a number, the amplitudes, and the durations of the significant deflections within a portion of the averaged electrocardiographic signal.