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Study Urges Better Heart Implant Device Tracking

EKG graphic

(PublicDomainPictures, Pixabay)

22 June 2015. Current methods of monitoring implanted heart devices, conclude researchers at University of California in San Francisco, may not be adequate for spotting the number of problems with the devices leading to patients’ deaths. The findings of the team led by UCSF cardiologist Zian Tseng were reported today in the journal JAMA Internal Medicine (paid subscription required).

Tseng and colleagues looked into the role of cardiac implantable electronic devices or CIEDs, including pacemakers and implantable cardioverter-defibrillator, in the sudden deaths of individuals with these devices. “With a vast majority of out-of-hospital sudden deaths evaluated by medical examiners or coroners,” says Tseng in a university statement, “CIED problems are often missed in the postmortem investigation, as they are not part of the routine evaluation.”

Implanted heart devices are designed to correct for arrhythmias or irregular heart rhythms, either at a too fast or slow rate or in irregular patterns. Pacemakers control irregular heart rhythms with electrical pulses at the correct beat, to correct for high or low beating rates. An implantable cardioverter defibrillator helps control life-threatening arrhythmias with electric shocks when sensing an abnormal heart beat that can lead to cardiac arrest.

While physicians and manufacturers monitor that performance of heart devices implanted in their patients and customers, the only common system tracking the these devices across the industry is Manufacturer and User Facility Device Experience, or Maude, database maintained by Food and Drug Administration. Participation is mandatory for manufacturers, but voluntary for health care providers.

Health care providers are required to report when implanted heart devices may contribute to someone’s death, but the authors say more than 90 percent of sudden cardiac deaths occur outside hospitals, and autopsies of deaths from these devices are rarely performed. As a result, Tseng and UCSF colleagues collaborated with San Francisco’s medical examiner to perform autopsies on people who died from sudden cardiac deaths, who also had cardiac implantable electronic devices, starting in January 2011 through November 2013.

The autopsies included toxicology and histology tests, as well as device interrogations, looking for any issues with the device, such as hardware failures, algorithm malfunctions, or improper device selection. The results show 22 of the 517 people, or about 4 percent, who had sudden cardiac deaths were fitted with implanted heart devices, with 6 of the 22 dying from other than cardiac reasons.

The researchers found 11 of the 22 deaths — 4 of the people with pacemakers and 7 with ICDs — had device problems, including 3 hardware failures. Other problems included undersensing of irregular heart rhythms, programming errors, and incorrect device selection. A separate review of records for 712 people in San Francisco during the same 3 year period, shows 109 or 15 percent of these individuals died, including 7 with defibrillator issues.

Tseng says issues with cardiac implantable electronic devices need to more systematically tracked and evaluated. “Because these devices are intended to prevent sudden death,” he notes, “careful monitoring for potential device problems should include a complete postmortem investigation when sudden deaths occur in those with CIEDs.”

Read more:

Disclosure: The author wears a pacemaker.

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