Fig. 2.

Sustained ventricular fibrillation in rabbit ventricles initiated by rapid pacing at a period of 80 ms preceded by a conditioning period (15 min) of fast pacing at 250 ms in the same heart as shown in Fig. 1. A–E: optical signal during sustained fibrillation; color represents voltage. Frames show anterior and posterior views at 5 different times (600, 1,200, 1,800, 2,400, and 3,000 ms). F: spatial frequency domain showing a maximum frequency of about 10 Hz. When compared with the nonsustained VF episode shown in Fig. 1, a larger fraction of the tissue exhibits the maximum frequency. Color bar indicates frequency in hertz.