Click on image to view larger version.

Figure 2 Bipolar electrograms obtained from apical and basal segments of the left ventricular free wall. Vertical dotted lines mark the time points of steepest portion of initial bipolar QRS waveforms and end of T-wave. Note the apex-to-base direction of depolarization. The direction is reversed (base to apex) during repolarization in both subendocardium (arrow 1) and subepicardium (arrow 2). ECG = electrocardiogram.