Accidental ventricular fibrillation of the human heart. A study of excitability levels with alternating current.

With the use of electronic equipment in medical work an electrical hazard can not be completely avoided. The danger for the patient lies in an accidental ventrical fibrillation induced by a current passing through the body. Thresholds of vulnerability for such currents were determined in dogs as well as on the human heart during cardiopulmonary bypass. Various electrode positions were tested and the minimum current of induction was measured. The lowest current producing fibrillation of the human heart was 100 muA. At the electrode surface the density of the electrical field then was 6-14 muA/mm2. In our routine procedure during open-heart surgery, the mean value for induction was found to be 600 muA.