Closed loop stimulation reduces the incidence of atrial high-rate episodes compared with conventional rate-adaptive pacing in patients with sinus node dysfunctions.

AIMS: Subclinical atrial fibrillation (AF) is associated with increased risk of progression to clinical AF, stroke, and cardiovascular death. We hypothesized that in pacemaker patients requiring dual-chamber rate-adaptive (DDDR) pacing, closed loop stimulation (CLS) integrated into the circulatory control system through intra-cardiac impedance monitoring would reduce the occurrence of atrial high-rate episodes (AHREs) compared with conventional DDDR pacing. METHODS AND RESULTS: Patients with sinus node dysfunctions (SNDs) and an implanted pacemaker or defibrillator were randomly allocated to dual-chamber CLS (n = 612) or accelerometer-based DDDR pacing (n = 598) and followed for 3 years. The primary endpoint was time to the composite endpoint of the first AHRE lasting ≥6 min, stroke, or transient ischaemic attack (TIA). All AHREs were independently adjudicated using intra-cardiac electrograms. The incidence of the primary endpoint was lower in the CLS arm (50.6%) than in the DDDR arm (55.7%), primarily due to the reduction in AHREs lasting between 6 h and 7 days. Unadjusted site-stratified hazard ratio (HR) for CLS vs. DDDR was 0.84 [95% confidence interval (CI), 0.72-0.99; P = 0.035]. After adjusting for CHA2DS2-VASc score, the HR remained 0.84 (95% CI, 0.71-0.99; P = 0.033). In subgroup analyses of AHRE incidence, the incremental benefit of CLS was greatest in patients without atrioventricular block (HR, 0.77; P = 0.008) and in patients without AF history (HR, 0.73; P = 0.009). The contribution of stroke/TIA to the primary endpoint (1.3%) was low and not statistically different between study arms. CONCLUSION: Dual-chamber CLS in patients with SND is associated with a significantly lower AHRE incidence than conventional DDDR pacing.

Reduction of admissions for urgent and elective pacemaker implant during the COVID-19 outbreak in Northern Italy.

AIMS: The coronavirus disease-19 (COVID-19) outbreak has been recently associated with lower hospitalization rates for acute coronary syndromes. Aim of the study was to investigate whether a similar behaviour is observed in admissions for urgent pacemaker implant. METHODS: This retrospective study included 1315 patients from 18 hospitals in Northern Italy with a high number of COVID-19 cases. Hospitalization rates for urgent pacemaker implant were compared between the following periods: 20 February to 20 April 2020 (case period); from 1 January to 19 February 2020 (intra-year control period); from 20 February to 20 April 2019 (inter-year control period). RESULTS: The incidence rate of urgent implants was 5.0/day in the case period, 6.0/day in the intra-year control period and 5.8/day in the inter-year control period. Incidence rate in the case period was significantly lower than both the intra-year [incidence rate ratio (IRR): 0.81, 95% CI 0.67-0.99, P = 0.040] and inter-year control periods (IRR: 0.79, 95% CI 0.66-0.95, P = 0.012); this reduction was highest after the national lockdown (IRR 0.68, 95% CI 0.52-0.91, P = 0.009). The prevalence of residents in rural areas undergoing urgent pacemaker implant was lower in the case period (36%) than in both the intra-year (47%, P = 0.03) and inter-year control periods (51%, P = 0.002). Elective pacemaker implants also decreased in the case period, with the incidence rate here being 3.5/day vs. 6.4/day in the intra-year (-45%) and 6.9/day in the inter-year period (-49%). CONCLUSION: Despite severe clinical patterns, the COVID-19 outbreak has negatively affected the population presentation to Emergency Departments for bradyarrhythmias requiring urgent pacemaker implant in Northern Italy. This mainly occurred after the national lockdown and concerned patients living in rural areas.