Threshold 60-Hz Current Required for Ventricular Fibrillation in Subjects of Various Body Weights

This paper reports the threshold 60-Hz alternating-current values required to induce ventricular fibrillation when the current is applied to electrodes at different sites on the surface of the bodies of rabbits, puppies, one monkey, dogs, goats, and ponies. It is shown that for a given body weight, the duration of exposure to current influences the fibrillation threshold; exposure times shorter than 1 s require more current. For a given duration of current flow, the threshold current for fibrillation is a function of body weight and electrode location. The lowest current for fibrillation was required with lead III (left forelimb-left hindlimb) and lead I (right-left forelimbs) required the highest current. For a 5-s exposure, the threshold current for fibrillation varies almost as the square root of body weight (W), the general expression being I = KW¿, where ¿ is nearly 0.5. Values for K and ¿ are presented for leads I, II, and III.