No need to panic over “pacemaker death probe”

X-ray of pacemaker and heart pump

“Pacemaker death probe” was the rather alarmist headline on the front page of the Sunday Express on 10 August 2015.

This story was subsequently reported in the Mail Online and also mentioned in the BBC News review of the newspapers, both on television and in print.

The story was based on research carried out in San Francisco. It was led by Zian Tseng from the University of California and was published in the journal JAMA Internal Medicine. From January 1 2011 to November 30 2013 there were 517 deaths, of which 14 had a pacemaker and 8 had an implantable cardioverter defibrillator (ICD).

Post-mortem examinations were performed and the devices were looked at. There was cause for concern about the device in four of the 14 pacemaker deaths, although in one of those it was judged to be pneumonia rather than the pacemaker failure that led to the death. There was concern for concern about the device in seven of the eight ICD deaths, five of which involved the ICD undersensing or failing to sense a potentially life-threatening heart rhythm. This is not the same as saying that the devices had caused the deaths or are “killing patients”. 

Modern permanent pacemakers are extremely reliable

It’s important to remember that in the UK, all ICDs and many permanent pacemakers are inserted because of a life-threatening heart condition. Without them, many thousands of patients would die.

The Express headline claims “Experts warn faulty heart implants could be killing 2,000 UK patients a year.” This appears to be based on calculating that because there were concerns about the device in 30 per cent of sudden cardiac deaths with devices in the study, this figure would apply to all sudden deaths with devices in the UK. But the numbers in the study were far too small for this kind of calculation to be reliable. 

The article also doesn’t distinguish between ICDs and pacemakers. The study found more problems with ICDs than with pacemakers, but in the UK the number of people with an ICD is much smaller than those with a pacemaker. Most of the issues with ICDs involved failing to sense a life-threatening heart rhythm, and that rhythm would probably still have happened if the ICD had not been implanted.

The study did not find that there were specific problems linked to particular brands or models of pacemaker or ICD.  

The researchers said there is currently a lack of information about device malfunction, and called for more to be done to monitor this. Dr Tseng said: “Because these devices are intended to prevent sudden death, careful monitoring for potential device problems should include a complete post mortem investigation when sudden deaths occur in those with CIEDs [pacemakers and ICDs].

“It is also important to recognize that we found that a third of device concerns were related to physician practices and present opportunities for practice improvement.”

If an ICD is recommended for you, the benefits far outweigh any risks

Professor Peter Weissberg, our Medical Director, said: “This study was carried out in the USA where choice of device and follow up arrangements may be more variable than in the UK, so we can’t assume that the same results would have been found in the UK.

“Modern permanent pacemakers are extremely reliable and, provided they undergo regular checks (which is part of routine management in the UK), sudden battery failure and wire fractures are rare events.

“ICDs are more complicated devices than simple pacemakers. All patients with ICDs have them fitted because they are at risk of sudden death without the device. For that reason, they should be closely monitored and should have their devices regularly checked. Often the effectiveness of the ICD is determined by the sensitivity of its settings. If the threshold for activating the device is too low, it can shock inappropriately causing great distress to the patient; if set too high, a potentially fatal rhythm disturbance may go untreated. 

“As with all medical interventions there are benefits and risks and all patients receiving these devices should be properly informed of what they are. In all patients for whom an ICD is recommended in the UK, the benefits far outweigh any risks.”

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