Electrocardiography is a non-invasive diagnostic procedure used to record the electrical signals generated by the heart muscle. The technique involves placing conductive electrodes on the skin surface, which detect changes in voltage corresponding to the electrical impulses that initiate and propagate through the cardiac conduction system. The resulting waveform patterns reflect the depolarization (the start of muscle contraction) and repolarization (the resting phase) cycles of the myocardium. This measurement allows for the assessment of cardiac rhythm and electrical pathways, providing crucial information used to diagnose various conditions, including arrhythmias, evidence of ischemia, and conduction system abnormalities.