Figure 7

Induction of fast rhythm by overdrive. A spontaneously discharging SAN was overdriven at 60 min^-1 for 30 s in panel A. In inset 1, the traces labeled with a star and a rhombus are shown superimposed in a, and the traces labeled with a rhombus and a dot are superimposed in b. In panel B, the SAN was overdriven at 120 min^-1 for 30 s. In inset 2, the traces labeled with a star and a rhombus were superimposed in a, and those with a rhombus and a dot in b.