Figure 32.4

Different representations of depolarization potentials of the same cardiac cycle in a normal subject. (a) Successive, instantaneous potential maps during the QRS; conventions are as in Fig. 32.2, except that the lines are isopotential and are measured in mV; the label above each map indicates the timing of the instantaneous map. (b) Integral map with the same conventions as in Fig. 32.2. (c) Autocorrelation map of the QRS interval; the same time interval is on both x- and y-axis, and each point on the map represents the correlation coefficient between instantaneous potential distributions at the instants of its x- and y-coordinates, using shades of gray from black for − 1. 0 to white for 1.0, as indicated on the scale at right. (d) Standard ECG reconstructed from leads corresponding to the standard ECG leads, extracted from the body-surface lead system.