Experience with malfunctioning leadless pacemakers: Troubleshooting and management during medium-term follow-up

Abstract

Background: The Nanostim leadless pacemaker (LP) was launched in 2012. However, the use of Nanostim LP was suspended because of safety concerns.

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 (mean age 83 ± 10 years; 65% male) who underwent Nanostim LP implantation between 2014 and 2016 at Isala Clinics were identified. Two patients were excluded from the analysis because of incomplete follow-up. The mean follow-up duration was 1114 ± 560 days.

Results: Nanostim LP malfunction occurred in 20 of 49 patients (40.8%). Premature LP battery failure was observed in 18 of 20 affected patients (90%). Furthermore, malpacing/malsensing was observed in 1 patient and mechanical dislocation of the Nanostim LP occurred in 1 patient. Of note, 17 of 18 Nanostim LPs with premature battery depletion (94%) showed normal device parameters 3 months before 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 3-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.

Keywords: Leadless pacemaker; Nanostim; Nanostim dysfunction; Nanostim early-life battery failure; Nanostim extraction; Nanostim management.