pacemaker

Pacemaker Malfunction

Pacemaker Malfunction Responsible for 2000 Deaths Per Year in the UK?

I just wanted to publish my response to the the Daily Mail and the Express who recently published an article claiming that 2000 deaths a year may be caused by faulty pacemakers. Essentially the paper manipulated a extremely weak statistical data set for scaremongering… the height of irresponsible reporting.

Here is the Daily Mail’s Article:

– Faulty pacemakers ‘killing 2,000 a year’: Third of unexpected deaths among patients thought to be caused by malfunctions
  • – Scientists say there is evidence implants could be ’cause of mortality’
  • – In total, a quarter of a million people have the devices in the country
  • – Research found 30 per cent of cases of sudden death were caused by mechanical flaws in the battery-powered devices 
  •  

By SOPHIE BORLAND FOR THE DAILY MAIL

A third of unexpected deaths among heart patients with pacemakers and similar devices could be caused by pacemaker malfunction, research suggests.
Scientists say there is evidence the implants could be a ‘leading cause of mortality’ and warn the findings are a ‘major concern’.
More than 40,000 patients are fitted with pacemakers in the UK a year, with another several hundred having Implantable Cardioverter Defibrillators (ICDs). In total, a quarter of a million people have the devices in the country.
 
Both are tiny battery-powered devices inserted into the heart to keep the rhythm regular. 
But University of San Francisco academics, who looked at 517 patients who suffered a sudden death, found that 30 per cent of cases were caused by mechanical flaws.
These included batteries running out, the implant being programmed incorrectly or the wrong type being fitted.
 
Around 14,000 patients die in the UK each year having been fitted with a pacemaker or ICD – of whom half die suddenly after having been in relatively good health.
This means that if the figures discovered by the American researchers also applied to this country, the implants would be to blame for more than 2,000 deaths a year. 
Professor Zian Tseng, who led the research, published in the Journal of the American Medical Association, said: ‘This study shows that a leading cause of mortality in the developed world could be attributed to ‘pacemaker malfunction’, which is a major concern.
‘In many cases these devices are saving lives but we assume they are infallible and they are not.’ He added that there was ‘an urgent need for a systematic surveillance of problems.’
 
Dr Paul Roberts, a cardiology consultant based at the University of Southampton, said: ‘The technology moves forward very quickly and there have been significant advances that have improved patients’ quality and length of life. Inevitably, occasionally, the technology fails us. 
It is important the healthcare profession and industry learns from these failures.’
The Medicines and Healthcare products Regulatory Agency – the watchdog for medical devices – said there were 2,400 reports of ‘adverse incidents’, including deaths, from pacemakers and ICDs between 2010 and 2014.
But it also pointed out they save at least 50,000 lives a year as without them patients would die from sudden heart attacks.
A spokesman added: ‘Cardiac implantable electronic devices enhance and, in many cases, save the lives of approximately 50,000 patients in the UK each year. Without these devices, patients would be at seriously increased risk.’
Below is my response…

 

I am a senior Cardiac Physiologist, Pacemaker and ICD specialist. 
I would like to clear up a few issues and hopefully reduce any undue concern among those with pacemakers.
Firstly the study looked at 517 patients whom had died of cardiac cause. This included 22 people whom had actually had pacemakers or ICD’s. I think that in itself this is remarkable… out of 517 deaths thought to be related to the heart only 4.2% had a cardiac device. This number of deaths attributed to pacemaker malfunction actually improves to 3.48% because 6 of those patients actually died of NON CARDIAC causes. 
 
More remarkable is that this ridiculous newspaper article uses a study size of n=22 (people with pacemakers) to then estimate the number of deaths attributed to pacemaker malfunction in a population of 14,000. Or to paraphrase this they looked at 0.157 % of a data set and then made assumptions for the remaining 99.842%.
 
Also I thought I would add some more information from the study for those interested…
 
Of the remaining 16 people with devices who actually died of a cardiac event- 13 died from a cardiac arrest. 
6 of these cardiac arrests occurred in patients with a simple bradycardia pacemaker.
This is NOT a pacemaker malfunction, brady pacemakers do not treat cardiac arrests, this is the job of ICD’s…. It is a little like asking a car to fly and then saying the technology failed when it ends up in the sea.
 
That leaves 10 patients or 1.9% of patients in this study. 
 
7 of these patients had ICDs’ and 6 did regrettably die from cardiac arrest due to the device failing to realise that the patient required defibrillation –  ‘Undersensing’ of a cardiac arrest can unfortunately occur in ICD’s and to reduce the risk of this occurrence the devices are often tested during implantation. A cardiac arrest is instigated under the controlled environment and the device is observed to make sure it does not undersense the arrhythmia. However, this testing in itself has a percentage risk of death, often outweighing the risk of undersensing occurring in the real world. Therefore a ‘sensing of cardiac arrest test’ is not performed as the cons outweigh the pros.
 
I would therefore be happy to remove these patients from the pacemaker malfunction category as it is a KNOWN limitation that pacemaker and ICD technology is making strides towards eliminating (newer devices are extremely proficient at detecting VF and I would also be interested in knowing the ‘age’ of devices in the study.)
 
This leaves 4 patients with an ICD/Pacemaker or 0.77 % of people in this study with ‘pacemaker malfunction’.
One had a possible lead fracture in a pacing dependent patient with Pneumonia (and was not confirmed to be pacemaker malfunction).
 
This leaves three patients with confirmed pacemaker malfunction… one battery suddenly depleted and there were two confirmed lead fractures. We are down to genuine hardware malfunctions leading to 0.58% of cardiac related deaths in the study’s population. 3 out of the 22 people that died and had a cardiac device.
 
We are AWARE there are limitations in hardware and the study raises an excellent point… we should look at the devices post mortem to help improve pacemaker/icd therapy and reduce any risk of device/programming shortcomings. 
 
I would like to finish with this conjecture (something that the daily mail seems particularly fond of)… 
 
Had all 517 people in this study had ICD’s or pacemakers in the first place then many of them would still be alive today.
 
Carl Robinson
Senior Cardiac Physiologist

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