S-ICDs need replacing after five years, says study

24th July 2015

New research on the first generation subcutaneous internal defibrillator (S-ICD) has shown that it needs to be replaced after five years, as expected.

But second generation devices that will last longer are already going through approval in Europe and America.

The small study also showed the life of the less-invasive device is not affected by the number of shocks it gives, and the need to later give patients a more traditional ICD is low.

S-ICDs are given to those who have had a cardiac arrest or doctors think are at risk of having one.

They can detect a life-threatening heart rhythm and give a shock to restore your normal heart rhythm.


But unlike traditional ICDs they do not have leads going into the heart and cannot also pace the heart. So they are only suitable for people who show no evidence of heart failure and have no need for a pacemaker. Because the leads are outside the heart, complications that can occur with ICD leads are reduced.

The research, led by Dr Dominic Theuns, from the Erasmus University Medical Centre in Rotterdam, has just been published in Circulation: Arrhythmia and Electrophysiology.

He said the study showed that the need to change to a traditional ICD because of a patient’s slow heart rate, the need for biventricular pacing (to help the heart beat in a more synchronised way) or the need for pacing to control fast heart rates was low.

He said longevity of the device was slightly less than the life-span of other devices but new longer-lasting second generation S-ICDs are coming.

Boston Scientific has already announced FDA and CE Mark approval of its Emblem S-ICD. The company says the new device will be 20 per cent thinner and is projected to last 40 per cent longer than the current S-ICDs.

The data in the new study came from 55 patients who had their S-ICDs implanted between December 2008 and February 2009 in Europe and New Zealand.

Those with the devices have the battery life checked regularly when they go to the clinic, and S-ICDs also send out an audible tone to alert patients that they need to promptly consult their doctors about their devices.

The safety and effectiveness of the devices has already been shown in an earlier study.