Leadless cardiac pacemaker in elderly patients: How old for a new technology?

Funding Acknowledgements

Type of funding sources: None.

Introduction

Leadless transcatheter pacemakers are considered as a safe and effective option for cardiac pacing in patients (pts) at higher risk of complications with conventional transvenous cardiac pacing.

Purpose

Our aim was to assess the clinical "real-life" feasibility and outcomes of leadless pacing in elderly pts in a high-volume center over a mid-term follow-up (FU) period.

Methods

Elderly pts (aged ≥ 75 years) who underwent leadless MICRA® system pacemaker implantation with a FU period above 3 months were included in this retrospective monocentric study.

Results

130 pts were included (84 ± 5.6 years old, male 66.2%). Indications were: Atrioventricular block (permanent 15.4%; transient 27.7%), atrial fibrillation bradycardia 50% and sinus node dysfunction 6.9%. Leadless system pacing was preferred over conventional pacing in pts with: transvenous pacemaker extractions due to infectious 18.5% or vascular 1.5% complications; active systemic infection and urgent need for cardiac stimulation 20%; complex conventional vascular approach 21.6%; severe tricuspid valve disease 1.5%; deterioration of general condition and clinical frailty 22.3%; shortly after transvalvular aortic valve replacement 8.5%. Among the pts, 6.2% had previous leadless Nanostim® device implantation with dysfunction of the system. Pts had either local anesthesia 13.2% or deep sedation 86.8%. The average fluoroscopy time was 4.3±2.9 minutes and number of device deployments before the final position ranged from 1 to 7 with a mean value of 1.5±1 positions. Pacing threshold during implant was 0.5±0.4 V at 0.24ms, only 4 pts (3%) had an implant threshold of >1.0 V at 0.24 ms. Two postoperative deaths were observed: 1 cardiac arrest related to myocardial dysfunction and consequent pulmonary edema in a patient with advanced heart failure, and 1 death secondary to myocardial perforation with need for surgical repair that occurred among the first implantations with an apical device position and a patient with multiple comorbidities. The total rate of major complications was 2.3% with only 1 vascular complication at the femoral puncture site. The median time from the leadless pacemaker implant procedure to discharge was 5±6.5 days (minimum 1 and maximum 40 days): 55.6% pts were able to leave the cardiology department within the first 72 hours. The mean FU period was 17 months ± 15 months with a mortality rate of 12.3% (cardiovascular impairment 5.4%; non cardiovascular-related deaths 6.9%). Increase in pacing thresholds was noted in 4 pts with subsequent stabilization; 92.2% of pts presented with thresholds lower than 1V at 0.24 ms. All pts remained free of infections during FU with no cases of device dislodgement observed.

Conclusion

Elderly pts are at higher risk of complications; our experience confirms their clinical frailty and underlines the favorable safety profile of leadless system pacing with a low rate of complications and stable pacing thresholds.

Characterization of indoor dust from Brazil and evaluation of the cytotoxicity in A549 lung cells

Over the past decade, ambient air particulate matter (PM) has been clearly associated with adverse health effects. In Brazil, small and poor communities are exposed to indoor dust derived from both natural sources, identified as blowing soil dust, and anthropogenic particles from mining activities. This study investigates the physicochemical and mineralogical composition of indoor PM10 dust samples collected in Minas Gerais, Brazil, and evaluates its cytotoxicity and inflammatory potential. The mean PM10 mass concentration was 206 μg/m(3). The high dust concentration in the interior of the residences is strongly related to blowing soil dust. The chemical and mineralogical compositions were determined by ICP-OES and XRD, and the most prominent minerals were clays, Fe-oxide, quartz, feldspars, Al(hydr)oxides, zeolites, and anatase, containing the transition metals Fe, Cr, V, Ni, Cu, Zn, Ti, and Mn as well as the metalloid As. The indoor dust samples presented a low water solubility of about 6 %. In vitro experiments were carried out with human lung alveolar carcinoma cells (A549) to study the toxicological effects. The influence of the PM10 dust samples on cell viability, intracellular formation of reactive oxygen species (ROS), and release of the pro-inflammatory cytokine IL-8 was analysed. The indoor dust showed little effects on alamarBlue reduction indicating unaltered mitochondrial activity. However, significant cell membrane damage, ROS production, and IL-8 release were detected in dependence of dose and time. This study will support the implementation of mitigation actions in the investigated area in Brazil.

Vasomotor rhinitis: clinical efficacy of azelastine nasal spray in comparison with placebo

The H(1) antagonist azelastine is used in nasal sprays for the treatment of allergic rhinitis, but its therapeutic efficacy in vasomotor rhinitis is unknown. We performed a multicenter randomized double-blind placebo-controlled study of the efficacy and tolerance of azelastine nasal spray in 89 adult patients with vasomotor rhinitis (confirmed by negative Phadiatop). Following a washout period, patients were treated for 15 days with one puff three times daily per nostril of azelastine (n = 44) or placebo (n = 45) nasal spray. Efficacy was evaluated by the reduction in symptomatology and by rhinoscopy. Intent-to-treat analysis revealed better results in the azelastine group for all assessed symptoms; the significance level was reached for nasal obstruction on day 15 (p = 0.042). Using per protocol analysis (in 85 patients complying with the protocol), the significance level was reached for nasal obstruction on day 15 (p = 0.017) and for the percentage of success in rhinorrhea (p = 0.023). In the azelastine group, rhinoscopy examination showed a significantly higher reduction in the inflammatory level and edema of the nasal mucosa (p = 0.03 and 0.02 for VAS on day 15 respectively, per protocol analysis). General efficacy assessment by the physician and the patient was in favor of azelastine (with significance levels <0.01). No drowsiness or serious adverse event was reported, and the frequency of mouth dryness and headaches was similar in the two treatment groups. The present study demonstrates the efficacy of azelastine nasal spray in the treatment of vasomotor rhinitis. The best achieved results were a decrease in nasal obstruction and mucosal edema. Further studies are required to investigate if this therapeutic benefit results from H(1) antagonism or from another, not well-characterized pharmacological action of azelastine.