Premature Trigger of ERI in Medtronic EnRhythm Devices

Melissa E. Middeldorp, Rajiv Mahajan, Adrian D. Elliott, Rajeev K. Pathak, Darragh Twomey, Lauren Wilson, Simon Stolcman, Dian Andina Munawar, Sharath Kumar, Dennis H. Lau, Prashanthan Sanders

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Background: Medical technology has made significant advances over the last few decades with smaller and more dynamic pacemakers. However, technical failures leading to premature replacement is a cause of concern. We present a series of Medtronic EnRhythm devices that reached premature elective replacement indicator (ERI). Methods: The database of Centre of Heart Rhythm Disorders was searched for EnRhythm device implantation from 2006 to 2011. Battery depletion <8.5 years was considered premature considering the projected average longevity to be 8.5–10.5 years. An unexpected premature ERI was defined when it was reached within 3 months of last normal check. Device follow-up was conducted every 3 months after advisory. Results: A total of 88 EnRhythm pacemakers were implanted. Over a median follow-up of 6.2 years (range: 0.3–9.2), 39 (44.3%) EnRhythm devices reached premature ERI. In 11 (28%), ERI was not recognized and patients were being investigated for other causes of unsteadiness or dyspnea prior to device check. Notably, three (7%) patients had premature ERI < 3.5 years. Ten (25.6%) had sudden and unexpected premature ERI. While asynchronous pacing was observed, there were no cases of absence of pacing. Conclusions: The rate of premature ERI for EnRhythm devices was 44.3%, significantly higher than reported by the manufacturer. Of concern, a sizeable proportion occurred unexpectedly, warranting more frequent reviews and empirical replacement in some patients. With the experience of the EnRhythm, appropriate monitoring strategies are recommended for future advisories.

Original languageEnglish
Pages (from-to)624-628
Number of pages5
JournalPACE - Pacing and Clinical Electrophysiology
Issue number6
Publication statusPublished - 1 Jun 2017


  • device recalls
  • elective replacement indicator
  • pacemaker
  • remote monitoring


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