Fig. 3

Defibrillation probability strength–duration curve. R² = 0.9885 (Weiss–Lapicque equation). Points indicate the electric field associated with 50% of defibrillation success (HEF₅₀) and the vertical lines indicate the confidence interval for 95%. Curve was fitted by Eq. (1) (rheobase = 4.17 ± 0.561 V/cm, chronaxie = 1.41 ± 0.235 ms), n = 10, each heart was defibrillated seven times (one time for each pulse duration)