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New £1.8m clinical trial to help reduce sudden cardiac deaths using implantable defibrillators

Updated: Sep 29, 2022

Southampton researchers have been awarded £1.8m to run a new clinical trial to improve treatment for people with heart failure.

The BRITISH trial aims to work out which patients could benefit from having an implantable cardioverter defibrillator (ICD) fitted under the skin in their chest.

Consultant cardiologists Dr Andrew Flett and Professor Nick Curzen at University Hospital Southampton will lead the trial. Professor Curzen is also a researcher at the NIHR Southampton Biomedical Research Centre.

Re-assessing who needs an implantable defibrillator

Researchers in 35 UK hospitals will recruit over 2,500 patients. These patients will all have non-ischaemic cardiomyopathy (NICM) and evidence of scarring in the heart. They will be randomly allocated to have an implantable cardioverter defibrillator (ICD) or not.

NICM is a common cause of heart failure, accounting for around a third of cases. Non-ischaemic refers to the fact that there is no narrowing of the coronary arteries (the most common cause of heart failure). Some patients with NICM can be at higher risk of sudden cardiac death due to dangerous, very fast heartbeats which can cause cardiac arrest.

ICDs can treat cardiac arrest and stop abnormal heart rhythms by delivering an electric shock to the patient’s heart. Current guidelines look at how well the heart is pumping to decide which patients get an implant, but this may not be the best method.

“These guidelines use an arbitrary cut-off of pump function,” says Dr Flett. “But a previous large trial has shown that most patients with NICM and an implantable defibrillator will never benefit from it. This also needs to be balanced against the risk of complications from an ICD. We want to find a better way to assess which patients will truly benefit from one of these devices before it is fitted.”

“Evidence suggests that it is actually scar tissue within the heart that causes abnormal heart rhythms. We believe this could be a better measure of the risk of sudden cardiac death for a patient, and so will identify patients most likely to need an ICD.”

Finding scarring in the heart

The trial will recruit NICM patients where an MRI scan has detected the presence of scar tissue in the heart. They will then be randomly allocated to one of two groups, with half fitted with an ICD.

They will use patient data to compare outcomes after three and five years in the two groups, to find out whether these patients need an ICD or not. If their results support it, all patients with NICM could have an MRI scan of their heart to look for scar tissue. If they do, they could be offered an ICD.

The trial, sponsored by University Hospital Southampton, is due to open next year across the UK. It will be funded by the British Heart Foundation and co-ordinated by the NIHR Southampton Clinical Trials Unit.

Dr Flett concludes, “If the BRITISH trial is successful, it could stimulate a change in international and UK guidelines for the treatment of NICM heart failure and implantable devices. We hope this would improve clinical outcomes for these patients in the future, and help reduce costs for our health service by ensuring only those who will benefit from ICDs have them fitted.”


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