Having an internal defibrillator (ICD) has a low but not zero risk

8th February 2016

Though internal defibrillators (ICDs) can be lifesaving in some people with cardiomyopathy, there is a very small risk associated with having the device, a new study confirms.

And young patients particularly face cumulative exposure to complications, so “careful consideration of the risks and benefits of having an ICD were needed before it was fitted".

Researchers led by Dr Joris Groot, from the Academic Medical Centre in Amsterdam, said: “The low but not zero risk of ICD-related mortality should be taken into account.”

He said having an ICD carried a significant risk in young patients of inappropriate shocks and complications developing in hospital and after discharge.

The study looked at the data from almost 5,000 patients. Twenty two per cent had ICD complications, including one in five having inappropriate shocks in follow up of over four years. One in 200 died from problems related to the device.

Annually, event rates were 4.7% for inappropriate shocks, 4.4% for other ICD-related complications, and 0.08% for ICD-related mortality.  

But Dr Groot said complications were almost always manageable, while sudden death was irretrievable.

The results were reported in the February issue of Heart Rhythm. 

The researchers said: "There is no doubt that an ICD can be lifesaving in inherited arrhythmia syndromes. However, in the young population, ICD therapy poses a problem. Just as they are exposed for decades to the risk of sudden death, they will also be exposed to the risks of ICD therapy for decades.”

They added that young patients are more vulnerable to ICD harm because of their active lifestyle and, in patients under 18, their growing thorax (chest region). The cumulative risk of complications was greater in young patients as they had a longer 'at-risk' period.

Although inherited heart rhythm problems were major causes of sudden death in young people, doctors should not expose young patients to the increased risk of ICDs unless it was clearly outweighed by the benefits." said Dr Robert M Hamilton, from the Hospital for Sick Children in Toronto, in an accompanying editorial.

While the ICD mortality and complication figures have remained steady over the years, the number of inappropriate shocks people get began to drop in 2008.

For more, see here.