Fig. 1

Pacing strength–duration curve. R² = 0.9609 (Weiss–Lapicque equation). Circles indicate the mean pacing threshold (E_T) and the vertical lines indicate standard error of the mean (SEM). Curve was fitted by Eq. (1) (rheobase = 0.16 ± 0.01 V/cm, chronaxie = 1.820 ± 0.20 ms), n = 10