Fig. 7
Representative bipolar electrogram (BEG) recordings taken in the penultimate cycle of the programmed electrical stimulation (PES) procedure after the final regular stimulus (S1) and the extrastimulus (S2), before (A) and 120 s after (B) introduction of 2 mM heptanol. The latencies of the successive peaks and troughs of the BEGs obtained in response to S2 stimulation were designated a, b, c, and d respectively. Those latencies obtained in response to S1 stimulation were designated a 0, b 0, c 0, and d 0. Application of paced electrogram fractionation analysis (PEFA) to BEG recordings obtained before (C) and after (D) introduction of 2 mM heptanol, yielding series of conduction curves. The critical S1S2 interval (arrow, point e) was defined as the S1S2 interval at which a 0 increased by 5%. The electrogram duration (EGD) was calculated from the difference between the latencies of the first and last peaks or troughs. The EGD ratio was defined as (a − d)/(a 0 − d 0). Activation latency plotted against EGD before (E) and after (F) introduction of 2 mM heptanol