If a patient in cardiac arrest is found with a bulge in the chest thought to be an artificial pacemaker, the first responder should:

When presented with a patient in cardiac arrest who has an artificial pacemaker, the appropriate action is to place the AED electrode to the left of the bulge indicating the pacemaker and several inches lower. This technique is critical because placing the electrode directly over the pacemaker can interfere with its function and may not allow for effective analysis and defibrillation.

Artificial pacemakers are typically implanted under the skin, and placing the AED electrode directly over the device may not accurately monitor the heart's rhythm, or it may even lead to the electrical energy of the AED interfering with the pacemaker's operation. Positioning the electrode to the side and lower ensures that it can properly monitor the heart's electrical activity and deliver a shock if needed without compromising the pacemaker's function.

Additionally, placing the electrodes on the lower left ribcage area would not be appropriate because that location may not provide optimal contact and could also still create issues with the pacemaker’s operation. Discontinuing use of the AED is not justified unless there are significant contraindications, and placing the AED electrodes inappropriately could hamper the chances of effectively resuscitating the patient.