Fig. 4

Ventricular effective refractory period (VERP) obtained during PES, before (n = 20) and 120 s after introduction of 0.1 mM (n = 5), 0.5 mM (n = 5), 1 mM (n = 6), and 2 mM (n = 5) heptanol (A). Asterisks indicate values that were significantly increased by heptanol (ANOVA, P < 0.05). Local critical interval, given by epicardial APD₉₀ − epicardial VERP, obtained before (n = 6) and after introduction of 0.1 mM (n = 5), 0.5 mM (n = 5), 1 mM (n = 5) and 2 mM (n = 5) heptanol (B). This was reduced by heptanol at all the concentrations investigated (asterisk; ANOVA, P < 0.05). Transmural critical interval, given by (endocardial latency + endocardial APD₉₀) − (epicardial latency + epicardial VERP), obtained before (n = 6) and after introduction of 0.1 mM (n = 5), 0.5 mM (n = 5), 1 mM (n = 5) and 2 mM (n = 5) heptanol (C). This was not altered by heptanol at any concentration (Student’s t test, P > 0.05)