Figure 1From: T Wave Alternans in high arrhythmic risk patients: Analysis in time and frequency domains: A pilot studyDiagram showing methodology for sampling analog ECG signal in X, Y and Z leads in a rested, supine patient during breath holding. 400 milliseconds of alternate T wave sequences were ensemble averaged for each lead and collected in matrix bins represented by X1, Y1, Z1 and X2, Y2 and Z2.Back to article page