ARREST trial

With funding from the British Heart Foundation and in collaboration with King’s College London, the London School of Hygiene and Tropical Medicine and St Thomas’s hospital, we are currently undertaking the ARREST trial; a study that will help paramedics and doctors decide the best treatment for patients who have a cardiac arrest outside of hospital.

The trial is now live in a small part of central London, and will be gradually rolled out to the rest of London. The trial will finish in 2020.

  • Why are we running the trial?

    A cardiac arrest occurs when a person’s heart suddenly stops beating, and is the most severe medical emergency. Evidence suggests that many cardiac arrests occur as a result of a sudden heart attack – which is when the supply of blood to the heart becomes blocked, usually by a blood clot. Find out more about cardiac arrests and heart attacks on our emergency heart care section.

    We regularly treat and transport patients who have a cardiac arrest caused by a heart attack to specialised hospital departments known as heart attack centres, which provide the specialist care the patient needs to treat their heart attack. Currently, patients who suffer a cardiac arrest, but do not have any clear evidence of a heart attack, are transported to the nearest emergency department where this kind of specialist treatment is not always available.

    Some experts believe all patients who have had a cardiac arrest might actually benefit from being taken directly to one of these specialist centres, even if there’s not any evidence they’ve had a heart attack. However, we don’t know this for sure, so therefore we are working with our partners to undertake a randomised trial to determine which option provides the best outcomes for these patients.

  • How will the trial work?

    Influential bodies such as the International Liaison Committee on Resuscitation and the British Heart Foundation have identified the need for a trial to investigate whether transporting out-of-hospital cardiac arrest patients to specialist heart attack centres might improve their long-term outcomes.

    The most conclusive way to do this is by a randomised, controlled trial comparing direct transport of patients to a heart attack centre versus transport to the nearest emergency department.

    The treatment pathway the patient falls into is chosen at random by a computer system, which means healthcare staff treating the patient are not able to influence which type of hospital the patient is taken to. This is important to reduce any potential bias in the trial results.

    All other aspects of the treatment these patients receive by us as the ambulance service will remain the same.

    These patients will be monitored in hospital and the study investigators will compare the outcomes for those who were transported to the heart attack centre with those who were taken to the emergency department.

    The trial is now live in a small part of central London, and will be gradually rolled out to the rest of London. The trial will finish in 2020.

  • Who will be enrolled in the trial?

    Adult patients who suffer a cardiac arrest outside of the hospital environment are eligible for the study, as long as there is no clear non-cardiac cause of their collapse.

    Those who are pregnant and those who go into cardiac arrest when they are already on the way to hospital will not be enrolled into the trial. Those who have evidence of a heart attack on their electrocardiogram (ECG) are also not eligible for the trial, as these patients are always transported to a heart attack centre.

    These patients will be monitored in hospital and the study investigators will compare the outcomes for those who were transported to the heart attack centre with those who were taken to the emergency department.