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.
Introduction:The vast majority of patients with pacemakers (PMs) who need MRI do not have MRI conditional pacemakers. Thousands of patients with non-conditional PMs have been safely scanned at experienced centers. However, pacemaker programming during scanning has varied and optimal setting are not known. We describe a case of bradycardia during MRI, and describe implications for programming. Methods: A 78 year old patient with a Medtronic Consulta CRT-P device with 5076 CapsureFix Novus leads in the RA and RV, and a 4296 Attain Ability Plus in the LV. He had suffered spine compression fractures requiring a lumbar MRI using a 1.5T scanner. History includes first-degree AV block with LBBB, and transient post implant AV block. There was a remote history of intermittent pacemaker dependency on clinical device checks. Preimaging pacemaker interrogation revealed 10% atrial pacing, RV pacing 99.4%, with heart rates distributed primarily between 60-100 bpm on histogram.Pre-MRI, the intrinsic rhythm was sinus at 75-80 bpm, and the pacemaker programmed ODO. For a majority of the scan, the rhythm remained consistent at 75-80 bpm, with pulse oximetry readings between 96% and 98%. When the patient was removed from the tube prior to contrast administration, the ECG and pulse oximeter tracings became erratic and unreadable. The patient started twitching in the upper extremities and was immediately removed from the MRI suite. The programming head was placed over his pacemaker and EGM revealed ventricular escape rhythm. The pacemaker was immediately programmed back to DDDR mode. The device was then interrogated and found to be functioning within normal limits. Results: Although the patient had no recent PM dependency, the post-MRI interrogation revealed that the patient had become pacemaker dependent during the MRI. In the 6 months post MRI, the patient progressed to complete heart block. Of the 840 MRI scans performed in t PM patients, this is the only case of intra-MRI bradycardia. (Figure 1) Conclusions: New onset PM dependency during MRI in patients with a stable pre-scanning instrinsic rhythm is rare, but may be provoked by sedation. Nonetheless, since it has the potential to result in serious bradycardias, are a potential complication, we have adopted new programming parameters that may provide antibradycardia support during MRI. Purpose: Down-sized leads have advantages during implantation and with regard to venous obstruction, but historically have resulted in increased complication rates. New requirements for MRI compatibility also have the potential to increase complication rates. A newly developed 6Fr bradycardia pacing lead designed for MRI compatibility was evaluated in a large prospective investigational device exemption clinical study. Method: The INGEVITY Trial is an ongoing, prospective, non-randomized, multi-center, study evaluating the safety, performance and effectiveness of the Active and Passive Fixation Leads implanted in patients who are care candidates for conventional cardiac pacing or cardiac resynchr...
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