Southampton heart experts first in UK to implant new leadless pacemaker defibrillator system

Heart experts at University Hospital Southampton (UHS) are the first in the UK to implant a new system to treat patients at risk of sudden cardiac arrest, as part of a global clinical trial.

In the UK there are over 30,000 out-of-hospital cardiac arrests a year where emergency medical services attempt to resuscitate the patient. The survival rate is low – just one in 10 people survive.

Certain types of abnormal heart rhythms (arrhythmia) occur in people with severe heart conditions. These can cause sudden cardiac death. This new leadless pacemaker defibrillator system could help more people with arrhythmia survive.

Life-saving combination of devices

The researchers fit two devices. Combined, these make the modular Cardiac Rhythm Management (mCRM) Therapy System. They work together to detect life-threatening arrhythmia, and prevent sudden cardiac arrest.

A subcutaneous implantable cardioverter-defibrillator (S-ICD) constantly monitors the patient’s heart rhythm. If it detects arrhythmia, a new leadless pacemaker (known as EMPOWER) sends electrical signals to correct the patient's heartbeat.

If this fails to work, the S-ICD then uses shock therapy to correct the heartbeat. This can be more painful and traumatic for patients, so is only used if absolutely necessary to prevent cardiac arrest.

Patients at UHS who need a defibrillator and have evidence of arrhythmia are being offered these devices as part of a new clinical trial.

The trial will assess the safety, performance and effectiveness of the mCRM Therapy System. It aims to enrol up to 300 patients across 50 centres in Europe, the US and Canada. This includes patients who need a new ICD or who already have an S-ICD system implanted. It is sponsored by manufacturer Boston Scientific.

No need for leads

Each year UHS implants more than 300 ICDs and checks almost 5000 patients who’ve had them fitted. Patients with only an S-ICD cannot receive pacing for slow heart rhythms. There is also no way to stop a sudden cardiac arrest due to an elevated heart rate.

Pacemakers are usually inserted under the skin via a cut in the chest, and connected to the heart via a lead threaded through the blood vessels. But this can cause problems, such as infections, obstruction of blood vessels and occasionally faults in the leads.

With this new procedure, the researchers insert the leadless device inside the wall of the heart. They do this using a small tube passed up through a blood vessel in the groin. This takes one hour using keyhole surgery.

David Mills, 56, a retired policeman from Southampton was the first patient in the UK to undergo the procedure.

“I feel very honoured to be part of this clinical trial, and to be the first person in the UK to have the device implanted, as it has given me the confidence to carry on a normal life,” he said.

“I hope the results of this trial will help to provide important insights so that soon more people can benefit. The clinical team at UHS have been very reassuring and approachable throughout, responding to any questions I may have had along the way and supporting me so well – I can’t thank them enough for what they have done.”

‘Major advance in treatment’

A medical team, led by Professor Paul Roberts, recently implanted the third EMPOWER device at UHS as part of the trial.

Prof Roberts, consultant cardiologist, has extensive experience in implanting leadless devices. He was also involved in establishing the training course for the procedure.

“This first in the UK implant of a leadless pacemaker combined with a defibrillator that is able to deliver pacing to stop life-threatening heart rhythms prior to the need for shock treatment represents a major advance in treatment for patients,” he said.

“Previously, patients implanted with only an S-ICD will not have had the advantage of pacing or may have been offered a replacement transvenous device which can pace first and then shock but will have carried the associated risks of leads in the heart – movement, fracture, infection – as well as more invasive surgery.

“The mCRM Therapy System will benefit a much larger patient population and enable the majority of lethal arrhythmias to be painlessly terminated without long-term risks associated with both shocks and conventional pacemakers.”