Experience with Malfunctioning Leadless Pacemakers: troubleshooting and management during medium term follow-up.

BACKGROUND: The Nanostim leadless pacemaker (LP) was launched in 2012. However, the use of Nanostim LP was suspended due to safety.

OBJECTIVE: The aim of this study was to report our experience with the management of malfunctioning Nanostim LPs, including premature battery depletion.

METHODS: Fifty-one consecutive patients (age 83 ± 10, 65% male) who underwent Nanostim LP implantation between 2014 and 2016 at Isala Hospital s were identified. Two patients were excluded from analysis due to incomplete follow-up. Mean follow-up duration was 1114 ± 560 days.

RESULTS: Nanostim LP malfunction occurred in 20/49 (40.8%) patients. Premature LP battery failure was observed in 18/20 (90%) of the affected patients. Furthermore, malpacing/malsensing was observed in 1 patient and mechanical dislocation of the Nanostim LP occurred in 1 patient. Of note, 17/18 (94%) Nanostim LPs with premature battery depletion showed normal device parameters three months prior to the diagnosis of (impending) premature battery failure. In 12 patients Nanostim LPs with a mean device age at the time of extraction of 1040 ± 467 days was successfully extracted without complications. Implantation of another LP or a transvenous device was successfully performed in all 20 patients with Nanostim LP malfunction. All known cases of early-life battery failure were identified during the three monthly follow-up consultations.

CONCLUSION: The incidence of Nanostim LP early-life battery failure was higher than previously reported. Nanostim LP extraction in an older population seems to be safe and effective. Three monthly follow-up seems to be effective at preventing in-between Nanostim LP related hospitalization.