Nanostim leadless pacemaker retrieval and simultaneous micra leadless pacemaker replacement: a single-center experience.

PURPOSE: The leadless pacemaker (LP) is a promising new technology in pacing therapy that avoids a generator pocket and transvenous lead-related complications. However, extraction experience with simultaneous re-implant of a leadless device remains limited. We sought to study the outcomes of Nanostim LP retrieval and simultaneous reimplantation of Micra LP. METHODS: Patients undergoing retrieval of the Nanostim LP and receiving a Micra LP implant between 2016 and 2018 at Mayo Clinic (Rochester, MN) were studied. The procedural and outcome data were collected from the electronic medical record. RESULTS: Nine patients underwent attempted Nanostim LP retrieval and 6 of these simultaneously received a Micra LP reimplant. All retrievals were considered chronic due to implant durations of > 1 year. Extraction procedures were completed with a success rate of 89% and simultaneous reimplantations were performed successfully in all cases with no major complications. Newly implanted Micra LP device function was normal at follow-up. Factors such as duration of device implant and device positioning appeared to impact ease of extraction. CONCLUSIONS: Retrieval of the Nanostim LP system and simultaneous replacement with an alternate Micra leadless device appears to be a feasible approach.

Real-world experience with leadless cardiac pacing.

BACKGROUND: Leadless cardiac pacing (LCP) has emerged as a new modality for permanent pacing. We sought to describe comparative outcomes between LCP and transvenous pacemakers. METHODS: Patients receiving LCP (Micra [Medtronic, Minneapolis, MN, USA] and Nanostim [St. Jude Medical/Abbott Laboratories, Chicago, IL, USA]) between 2014 and 2017 at the Mayo Clinic Heart Rhythm Enterprise practice (Rochester, MN, USA; Jacksonville, FL, USA; and Scottsdale, AZ, USA) were identified. We identified 1:1 age- and sex-matched controls receiving single-chamber transvenous ventricular pacemakers (TVP). Statistical analyses were performed with JMP 13.0.0 (SAS, Institute Cary, NC, USA). RESULTS: Ninety patients underwent LCP implantation (73 Micra and 17 Nanostim) with a median follow-up duration of 62 (interquartile range 28-169) days. Both groups had 100% successful device implant rates. There were no differences in procedure-related major (0% vs 1%) or minor complications (8% vs 3%) in the LCP versus TVP groups (P > 0.05). Excluding Nanostim patients, there was a lower rate of device-related revision or extraction in the Micra versus TVP groups (0% vs 5%, P = 0.028). Device endocarditis was more common in the TVP group (0% vs 3%, P = 0.04). Estimated longevity was greater for the LCP group (median 12.0 vs 10.0 years, P < 0.0001). An increase in severity of tricuspid valve regurgitation (TR) by ≥2 grades occurred in none of the LCP patients, and in 19% of the TVP patients (P = 0.017). CONCLUSION: There are no significant differences in procedural complications among patients receiving LCP versus TVP. The Micra group had lower rates of device-related revision/extraction compared to the TVP group. Patients with leadless pacemaker were less likely to develop endocarditis or worsening TR.

Effect of ventricular pacing lead position on tricuspid regurgitation: A randomized prospective trial.

BACKGROUND: Pacing lead-related tricuspid regurgitation (TR), a recognized complication of ventricular pacing lead implantation, may be affected by lead position or diameter. OBJECTIVE: This study sought to determine the effect of ventricular pacing lead position and diameter on pacing lead-related TR. METHODS: A randomized prospective trial compared pacing leads in the right ventricular apex (RVA), right ventricular septum (RVS), or left ventricle via the coronary sinus (LV-CS) in a 1:1:1 fashion. Patients undergoing implantable cardioverter-defibrillator lead implantation in the RVA (RVA-ICD) were enrolled in a comparison group. Patients with preexisting moderate or greater TR were excluded. Prospective clinical evaluation, transthoracic echocardiograms, and device interrogation occurred 24 hours and 12 months after device implantation. RESULTS: Sixty-three patients undergoing pacemaker implantation were randomized to RVA, RVS, or LV-CS pacing, and 48 RVA-ICD patients were enrolled as a comparison group. At 12 months, 6 patients (6.4%) developed moderate or greater TR. Moderate or greater TR was not significantly different between groups if analyzed by intention to treat (RVA 5.9%, RVS 10.0%, LV-CS 6.7%, and RVA-ICD 4.8%) or if analyzed by final lead location (RVA 4.8%, RVS 10.5%, LV-CS 8.3%, and RVA-ICD 5.1%). Ventricular lead-related complications occurred in 3 patients with right ventricular leads (3.2%) and 2 patients with LV-CS leads (11.1%) (P = .184). CONCLUSION: Neither pacing lead position nor diameter appears to affect TR development significantly. LV-CS leads failed to achieve a statistically significant reduction in TR as compared with right ventricular leads.