AED Frequently Asked Questions

  • Why does the defibrillator only advise a shock some of the time?
    The AED will shock two different types of heart rhythms: ventricular fibrillation and ventricular tachycardia. There are other types of rhythms that may be presented to the AED but they can’t be treated with a defibrillatory shock so the only form of treatment until the ambulance arrives is high-quality CPR. This is why ZOLL AEDs not only provide a shock but also coach the rescuer in delivering high-quality CPR using our Real CPR Help technology.
  • What is Real CPR Help?
    Real CPR Help, a technology developed by ZOLL and incorporated into all our defibrillators, provides real-time feedback to the rescuer on the rate and depth of chest compressions during CPR. This technology is clinically proven to improve the quality of CPR delivered to victims of a cardiac arrest by up to 277%.
  • What is the life of the batteries?
    The batteries supplied with the AED Plus and ZOLL AED 3 last up to 5 years in standby mode.
  • What is the life of the electrodes and are they reusable?
    The CPR-D-padz and the CPR Uni-padz electrodes that are supplied with the AED both have a shelf life of 5 years and are designed to be used only once.
  • Can the electrodes supplied with ZOLL AEDs be connected to any other defibrillator, for instance those used by the ambulance service?
    The electrodes can be connected directly to any other ZOLL defibrillator. If the ambulance service or hospital use equipment manufactured by another source then adaptors may be used to connect the ZOLL electrodes to the alternative device.
  • Can the AED Plus and ZOLL AED 3 be used by anyone even if they haven’t had any training?
    The Resuscitation Council (UK) take the view that an AED can be used safely and effectively without previous training, however when possible, training should always be given. The AED Plus and ZOLL AED 3 have both been designed to provide graphical, written and audible prompts to help the rescuer as much as possible through the resuscitation process.
  • Is it difficult and costly to maintain the ZOLL AEDs?
    Once installed, ZOLL AEDs have the lowest total cost of ownership. The AED Plus pads and batteries last 5 years and has the lowest cost of ownership when only adult pads are needed. Because the ZOLL AED 3 incorporates a 5 year universal electrode pad that lasts 5 years and can be used on adults or children, it has the lowest cost of ownership when both paediatric and adult pads are required.
    Unless used, there is nothing to replace or buy for up to 5 years. The AED Plus also carries out regular automated self tests to ensure a constant state of readiness. If the device detects a fault or the need for battery/ electrode replacement, the indicator window will display a red cross X and will be accompanied by an intermittent beep.
  • ZOLL AEDs are not the cheapest on the market – Why should I choose ZOLL?
    There are cheaper devices on the market, but they do not provide the same CPR coaching support that the ZOLL AEDs offers. So you need to ask the question, “Is good quality CPR important in the survival of a cardiac arrest patient? Would you and your staff be confident in delivering consistent and good quality CPR over a prolonged period of time – in a pressured rescue situation? To deliver high-quality CPR, you need a ZOLL AED. No other device on the market can provide this level of support.
  • Can I be held liable?
    In the UK there is currently no law that protects bystanders from performing CPR in a cardiac arrest situation. However, legislation was introduced in October 2007, under the Mental Capacity Act, that stipulates if the casualty lacks capacity to make a decision themselves, which would be the case in a cardiac arrest, the rescuer can perform CPR if they believe it is in the best interest of the casualty. To date, there have been no reported cases where a successful claim has been made against a rescuer that has helped resuscitate a casualty in an emergency.
  • Should AEDs only be used by medical professionals?
    AEDs have been designed specifically with the lay rescuer in mind, which is why ZOLL AEDs include graphical, written and audible prompts that guide them through the full Chain of Survival and help them to perform high-quality CPR and deliver a shock when necessary. If no shock is advised CPR is critical in order to pump oxygenated blood around the body to the vital organs until the ambulance arrives and takes over.
  • What do I do if I have a technical fault with a ZOLL device?
    For any technical difficulties, please contact ZOLL’s UK-based technical service team on: Telephone Number: 0808 168 5000 (Freephone) or 01928 241 701 or E-mail:

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