PHYSICIAN'S AUTHORIZATION REQUIRED FOR PURCHASE. Children weighing less than 55 pounds (25 kg), including infants, should be treated using HeartStart Infant/Child SMART Pads. These pads instruct the defibrillator to reduce the energy of its shock from 150 to 50 Joules (J). The Infant/Child Pads cartridge is marked with an indication of the appropriate weight and with a teddy bear icon for easy identification. One Set of Infant/Child Pads.