Heart failure patients in Scotland are being recruited into a groundbreaking new clinical trial to test the benefits of a defibrillator implant.

Clinicians in Edinburgh have begun recruiting candidates who suffer from a condition called dilated cardiomyopathy (DCM) which can cause their hearts to beat out of control, leading to sudden cardiac death.

The study will investigate whether fitting a "sophisticated pacemaker" known as an implantable cardioverter defibrillator (ICDs) into the chests of DCM patients who have not yet experienced an abnormally fast heartbeat - but who do have evidence of scarring in their heart - reduces deaths rates over time.

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The ICD, which is inserted under the skin, can detect when a patient goes into this very fast cardiac rhythm and stop it by delivering an automatic electric shock to the heart.

The study will split participants into an ICD group and a control group who will receive an alternative device, known as an implantable loop recorder, which simply monitors the heart for signs of abnormal rhythm.

The Herald: The ICD is implanted under the skin where it can detect, and 'shock', irregular heartbeatsThe ICD is implanted under the skin where it can detect, and 'shock', irregular heartbeats (Image: Southampton Clinical Trials Unit)

The UK-wide trial, which aims to recruit over 2,500 patients and also includes sites in Aberdeen and Glasgow, has been funded with £1.8 million from the British Heart Foundation.

ICDs are already given to patients who have experienced an life-threatening cardiac arrhythmia, but there is less clarity on which patients should be prioritised for the devices on a precautionary basis.

However, recent evidence suggests that scar tissue may increase the risk.

Professor Marc Dweck, the chair of clinical cardiology at Edinburgh University who is leading recruitment in the capital, said: "Patients with dilated cardiomyopathy do have a risk of dying suddenly, usually due to very fast heart rhythms.

"The problem is that it's quite hard to predict which patient is going to develop this particular problem.

"We have preventative treatments - ICDs - but we can't put them in everyone because they're very expensive and when we put stuff into the heart it can go wrong and cause complications, so we just need to get much smarter at putting them into the right patients.

"There's quite a lot of controversy about who should get it and who shouldn't.

"The traditional approach was just to select the patients whose heart function is severely impaired, but there's some data recently that questions whether that is the right thing to do.

"Now we think that a better way of protecting the people at highest risk is to give ICDs to those patients with scarring on their ventricles, but that's what this trial is going to test."

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Prof Dweck expects to enrol at least 10 to 20 patients for the Edinburgh arm of the study.

Suitable patients attending cardiology clinics will be identified using MRI scans to detect signs of scarring.

Around a third of patients with DCM have scarring on their hearts.

The Herald: Phil O'Donoghue surgery as trial gets underwayPhil O'Donoghue surgery as trial gets underway (Image: SCTU)

The Herald: Phil O'DonoghuePhil O'Donoghue (Image: SCTU)

A 53-year-old heart failure patient from Hampshire, Phil O'Donoghue, was the first to join the trial in June this year when he underwent surgery at University Hospital Southampton. 

The trial is being coordinated nationally by the NIHR Southampton Clinical Trials Unit.

It remains unclear what causes people to develop DCM.

While some cases are inherited or occur after viral infections, most are unexplained - affecting children as well as adults.

"I have been involved in this field for over 10 years now and this is a trial I have been waiting to see for quite a long time," said Prof Dweck.

"For people in this field, this is something we really need to test to see if this strategy works."

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Professor Sir Nilesh Samani, medical director of the British Heart Foundation, said:
“ICDs are crucial devices to treat sudden cardiac arrest and save lives.

"But it is important that we continue to establish exactly which patients need them, so that people who are unlikely to benefit do not have to undergo invasive procedures unnecessarily."

Dr Andrew Flett, the trial's chief investigator for the trial, added: “For many patients who go through the procedure of having a defibrillator fitted, they will never actually see the device triggered and may not need it.

"We therefore want to find a better way to assess which patients will truly benefit from one of these devices."