Our wish to know more about the paths taken by electrical currents in electroacupuncture (EA) with special reference to the heart, particularly in patients with an implanted pacemaker, prompted us to undertake this study. Using ourselves as subjects, we have developed a safe oscillographic method to detect, visualise and record the EA currents that avoids the use of equipment requiring mains electricity. After two trials with unsatisfactory equipment, we found that the newly developed model 3425 PicoScope™ (Pico Technology Ltd), with a four channel differential amplifier input connected to a laptop PC operating in battery mode, satisfied our criteria. With this recording system, we carried out two sets of experiments in which EA was provided by a Cefar acus4™ stimulator. The results confirm that the placement of a pair of acupuncture needles for EA can be used to predict the paths taken by the stimulating currents, and thus their areas of likely influence. When the needles are placed in closely adjacent acupuncture points in a limb, there is little or no detectable spread of the currents along the limb or into the chest. By contrast, when the needles are placed far apart, the electrical currents spread widely. Thus, when each of a pair of needles is placed in a point on opposite arms, the electrical currents recorded in the area of the pectoral muscles is of an order that might trigger an abnormal cardiac rhythm in a susceptible heart or activate a cardiac pacemaker incorporating an intracardiac defibrillator (ICD). Our results confirm the guidelines for EA safe practice recommended by the British Medical Acupuncture Society (BMAS) to avoid adverse events, ie EA should not be applied such that the current is likely to traverse the heart. We can now be confident that electric fields generated by pairs of needles below the knee or elbow do not create detectable currents in the chest. It is likely that similar results would be obtained with the use of transcutaneous electrical nerve stimulation (TENS) but this remains to be established by additional experiments.