1. A computer-assisted method for selecting ECG complexes for further evaluation, the method comprising: receiving a recorded patient ECG signal comprising a plurality of m ECG complexes; and using a processor to evaluate ECG complexes of the plurality of m ECG complexes, and to identify a subset of n ECG complexes of the plurality for further evaluation, where n is greater than two and less than m, and wherein the n ECG complexes of the identified subset have a highest degree of similarity to one another relative to any other possible subset of n ECG complexes of the plurality of m ECG complexes.