OBJECTIVE Because death has occurred with injury involving voltage as low as 50 to 60 V (probably the result of arrhythmias), we wanted to evaluate the necessity of cardiac monitoring in children sustaining electrical injuries with 120 or 240 V. METHODS The charts of 151 children who presented to the emergency department between April 1, 1989, and March 31, 1992, were reviewed. METHODS A tertiary care pediatric teaching hospital. RESULTS A total of 141 patients presented with 120-V electrical injuries. An ECG or a rhythm strip was performed in 93 patients (66%), and no arrhythmias were believed to have resulted from the electrical injury. Cardiac monitoring was done in 113 patients (80%) for a mean duration of 7.4 +/- 6.6 hours (median, 4 hours), and no arrhythmias were observed. Creatine phosphokinase levels were measured in 62 patients (44%) with a mean of 137 +/- 154 U/L (median, 96 U/L). The levels were elevated in 8 patients (12%), with no clinical significance. Follow-up was done in 112 patients (77%), and no significant adverse outcome was reported. There were only 10 patients in the 240-V group; no arrhythmias or adverse outcomes had occurred. CONCLUSIONS On the basis of our findings, initial cardiac evaluation (ECG) and monitoring do not appear to be necessary in children sustaining household electrical injuries (120 and 240-V); however, the significance of loss of consciousness, tetany, wet skin, or current flow that crossed the heart region could not be determined in our investigation. Therefore, cardiac monitoring should be performed if one of these factors is present.