Implantable Cardioverter Defibrillators (ICDs) work by delivering an electric shock to the heart if its rhythm is abnormally disturbed. Although ICDs are an effective treatment for those at risk of sudden cardiac arrest, this new device is a Subcutaneous (under the skin) Implantable Cardioverter Defibrillator (S-ICD) which simplifies the surgery and could lead to more patients receiving effective and better-tolerated treatment to protect them against the risks of sudden cardiac death.
The subcutaneous implantable cardioverter defibrillator (S-ICD) device has two main benefits over currently used devices. Firstly, as there are no leads actually placed into the heart, their removal or replacement is much simpler, therefore reducing the potential risk for infection.
In addition, the S-ICD may also have a better capacity than other ICDs to discriminate between normal and abnormal heart rhythms and it is strongly anticipated that patients with this device will receive fewer unnecessary shocks.
Frequently asked questions:
Implantable defibrillators have been in use since the early 1980s. Worldwide more than 250,000 are prescribed each year for patients at perceived risk of sudden cardiac death. The current devices have a lead placed in the heart rather like a pacemaker but the new S-ICD has no lead inserted in to the heart.
Dr Andrew Grace and his team completed a significant proportion of the clinical development work for the new device at Royal Papworth Hospital. The device is manufactured in California.
This new work shows that not only is it possible to develop a device without any leads being inserted into the heart, but it is now clear, based on the substantial body of work completed, that the device has major benefits for the patient. As there are no leads actually placed in to the heart, their removal or replacement is much simpler, therefore reducing the potential risk for infection.
The observation that defibrillation could be achieved with a lead outside the heart and the development and regulatory approval of a device to actually deliver this should lead to more patients receiving effective and better tolerated treatment to protect them against the risks of sudden death.
Sudden death is currently responsible for more than 70,000 lives per year in the United Kingdom alone.
There are two main advantages - there are no leads in the heart and it should have better specificity than devices used currently. The increased specificity will mean that individuals receiving the device will have fewer unnecessary or inappropriate shocks.
Cameron Health Inc., based in San Clemente, Southern California.
The work started at Papworth on 13 December 2002 and the first commercial implant was on the 25 July 2009.
We placed two devices on the 25 July 2009. One was a woman in her 60s for ‘primary prevention’ who had not had any previous life-threatening events herself but has a powerful family history of sudden death. The second device was in a man in his 40s with a previous history of life-threatening events.
In both patients at the time of the surgical implant a life-threatening event was induced and the device seen to recognise and correct it. All the work we have done indicates that if such an event occurs in a real-life setting, then the device will correct the situation in a matter of seconds and save the life of the patient.
These procedures require a team approach. The two senior medical members of the team are Dr Andrew Grace and Dr Amo Oduro, both of who have worked on the project since its inception. Those assisting include cardiac technicians, specialist nurses, theatre nurses, theatre assistance, radiographers and representatives from the manufactures.
The procedures each took more than an hour to complete. It is anticipated that with more experience the time to complete an operation will come down considerably.
We generally anticipate that any individual who needs protection from sudden death and in whom there is no evidence of heart failure or need for a pacemaker could benefit.
Some patients who need an ICD will still need a lead in the heart. The two particular groups will be those who need cardiac resynchronisation therapy (for heart failure) and those who also have a slow pulse who are also in need of pacemaker therapy.
It is anticipated that the costs will be broadly comparable to ICDs.
Any risk of infection with current devices particularly involves the leads placed in the heart - so if these are fewer, then the rates and the risks of infection should both be less.