Classic ECG interpretation is based on identification of waveforms and deductive analysis of the electrical events the waveforms represent. The more in depth the understanding of electrophysiologic cellular interactions, the more precise the interpretation of ECG tracing. Surface ECG has limitations; yet, it is accurate in representing myocytes' pathologic behaviors. Recent advances have improved understanding of arrhythmias by reconstructing their mechanisms of induction and maintenance and exploring cellular channel dysfunction. Translating this knowledge to ECG analysis will create the link that allows ECG interpretation to reach the level of precision electrocardiology. This article presents cases illustrating new techniques for electrophysiologists.