Introduction: The efficacy and safety of leadless cardiac pacemakers (LPMs) as an alternative to conventional transvenous cardiac pacing have been largely reported. The first generation of the Micra^TM transcatheter pacing system (VR; Medtronic) was able to provide single‐chamber VVI(R) pacing mode only, with a potential risk of pacemaker syndrome in sinus rhythm patients. A second‐generation system (AV) now provides atrioventricular synchrony through atrial mechanical (Am) sensing capability (VDD mode).Objective: We sought to compare VR and AV systems in sinus rhythm patients with chronic ventricular pacing (Vp) for complete atrioventricular block.Methods: All consecutive patients implanted with an LPM in our department for complete atrioventricular block were retrospectively screened. Patients with atrial fibrillation, sinus dysfunction, or Vp burden 66% rate. An E/A ratio <1.2 as measured on echocardiography was the only independent predictor of accurate atrial mechanical tracking (p = 0.01). One‐year survival rate was similar in both groups. Five patients in the VR and 0 in the AV group eventually developed pacemaker syndrome within 1 year post‐implantation (p = 0.02).Conclusion: In sinus rhythm patients with chronic Vp for complete atrioventricular block implanted with an LPM, the atrial mechanical sensing algorithm allowed significant atrioventricular synchrony in most patients and was associated with no occurrence of—otherwise rare—pacemaker syndrome.

Background: Atrial fibrillation (AF) patients represent a clinically complex, heterogeneous population comprising multiple homogeneous cohorts. Purpose: We aimed to identify the common clinical phenotypes of AF patients and compare clinical outcomes between these subgroups. Methods: A 1% representative sample of all AF patients hospitalized between 2010 and 2019 was identified from the French national database. Agglomerative hierarchical cluster analysis was performed using Ward’s method and squared Euclidian distance to derive the clusters of patients. Cox regression analyses were used to evaluate outcomes including all-cause death, cardiovascular death, non-cardiovascular death, ischemic stroke, hospitalization for heart failure (HF) and composite of ventricular tachycardia, ventricular fibrillation and cardiac arrest (VT/VF/CA) over a mean follow-up period of 2.0 ± 2.3 years. Results: Four clusters were generated from the 12,688 patients included. Cluster 1 (n = 2375) was younger, low cardiovascular disease (CVD)-risk group with a high cancer prevalence. Clusters 2 (n = 6441) and 3 (n = 1639) depicted moderate-risk groups for CVD. Cluster 3 also had the highest degree of frailty and lung disease while Cluster 4 (n = 2233) represented a high-risk cohort for CVD. After adjusting for confounders, with cluster 1 as the reference, cluster 3 had the highest risk of all-cause death, HR 1.24 (1.09–1.41), ARD (10.3%), cardiovascular death, HR 1.56 (1.19–2.06), ARD (3.3%), non-cardiovascular death, HR 1.20 (1.04–1.38), ARD (6.9%), hospitalization for HF, HR 2.07 (1.71–2.50), ARD (9.1%) and VT/VF/CA, HR 1.74 (1.20–2.53), (ARD 1.3%). Conclusions: Four distinct clusters of AF patients were identified, discriminated by the differential presence of comorbidities. Our findings suggest that hospitalized AF patients with moderate CVD risk may have a poorer prognosis compared to hospitalized AF patients with high CVD risk in the presence of lung pathology and frailty. This subgroup of patients may require more stringent management of existing comorbidities such as chronic obstructive pulmonary disease and sleep apnea, alongside their AF.

Background and Aims: Influenza infection triggers cardiovascular events, and vaccination confers cardiovascular benefit in high-risk populations. Its role in preventing incident atrial fibrillation (AF) and cardiovascular outcomes in clinical practice remains uncertain. These associations were evaluated using a real-world target-trial emulation framework. Methods: A retrospective cohort study was conducted using the TriNetX Global Collaborative Federated Research Data Network including adults with a routine healthcare visit in 2022. Influenza vaccination within the preceding year defined exposure; comparators had no recorded vaccination. A 1:1 propensity score matching across 65 baseline variables was applied. Outcomes included incident AF, cardiovascular events, and mortality, with subgroup analyses by age and baseline cardiovascular disease. Results: After matching, 276 888 patients (138 444 per group) were included with excellent covariate balance. During a mean follow-up of 2.7 ± 0.7 years, influenza vaccination was associated with a significantly lower risk of incident AF [hazard ratio (HR) 0.80, 95% confidence interval (CI) 0.76–0.84; P < .0001]. The absolute annualized incidence of AF was 0.9% in vaccinated patients vs 1.1% in non-vaccinated patients. Vaccinated patients also had lower risks of all-cause mortality (HR 0.85, 95% CI 0.82–0.89), myocardial infarction (HR 0.91, 95% CI 0.86–0.97), incident heart failure (HR 0.92, 95% CI 0.88–0.96), and cardiovascular-related hospitalization (HR 0.97, 95% CI 0.95–0.99). Associations were directionally consistent across age and cardiovascular disease subgroups, without significant effect modification. Conclusions: In a large retrospective observational real-world cohort, influenza vaccination was associated with lower risks of incident AF and multiple cardiovascular outcomes. These findings support vaccination as a potential upstream strategy for AF prevention and highlight the need for randomized trials specifically designed to address AF-related outcomes.