Spotlight on… implantable cardioverter defibrillators
After suffering a cardiac arrest during his country’s Euro 2020 match against Finland in June, Danish midfielder Christian Eriksen was fitted with an implantable cardioverter defibrillator (ICD). Find out more about this life saving treatment carried out at Barts Heart Centre.
Barts Heart Centre at St Bartholomew’s Hospital is the leading site in the UK for implantable cardioverter defibrillators (ICD) with its catheterisation labs implanting over 250 devices per year.
An ICD, a device similar to a pacemaker, sends an electrical shock to the heart that restarts the organ during a cardiac arrest so it can pump blood around the body again.
If the ICD senses the heart is beating at a potentially dangerous abnormal rate, it'll deliver an electrical shock. This helps return the heart to a normal rhythm.
ICDs are often used as a preventative treatment for patients thought to be at risk of cardiac arrest at some point in the future, such as those with inherited heat disorders or those who had suffered heart attacks, making their heart function severely reduced.
Eriksen’s treatment team said that this device was necessary after his cardiac arrest due to “rhythm disturbances and to prevent another arrhythmia, an abnormal heart rhythm”.
A conventional ICD has a special pacing lead that's implanted along a vein (transvenously).
For a subcutenoaus ICD, or S-ICD, the pacing lead is implanted under the skin (subcutaneously).
This means that potential risks are avoided, such as infection or the lead moving or wearing out over time, which requires extraction.
S-ICD are particularly suitable for younger patients or ICD patients at risk of infections such as those with diabetes or kidney disease. Most patients lead a normal life with their ICD and the battery lasts about seven years before changing, with a device check every year or weekly through a home monitor.
Transvenous ICDs are implanted in patients who need additional pacing for slow heart rhythms. These respond to rapid pacing to stop them or help resynchronise their hearts when the contractions are unco-ordinated.
Barts Heart Centre has four catheterisation labs dedicated to heart rhythm disorders which undertake ablation procedures and ICD or pacemaker implants.
Each year the lab also performs 1,500 ablations and 2,500 pacemaker procedures.
Professor Pier Lambiase, co-director of cardiovascular research at the Barts Heart Centre, said: “ICDs save thousands of lives around the world every year and the S-ICD has been a real innovation allowing the long term problems associated with leads in the heart to be avoided.
“I’m very proud of these procedures we do at St Bartholomew’s Hospital and arrhythmia patients should speak to their GP or treatment team if they believe they would benefit from having one fitted at St Bartholomew’s.”
The cath labs at Barts Heart Centre has also contributed to a large randomised controlled trial, The PRAETORIAN, that has recently been published in the New England Journal, where St Bartholomew’s was one of the main implanting centres.
This trial showed the S-ICD has a lower risk of lead complications and is as safe and effective as a transvenous ICD.
Professor Lambiase recently spoke to Boston Scientific about the science behind ICDs.
Main picture credit: Matthew Andrews