The HERO (HEart Rhythm management Optimisation of pacemaker recipients using remote monitoring) registry is an exploratory, single-centre, retrospective cohort study conducted at Rijnstate Hospital in Arnhem, the Netherlands. The study was approved by the local ethics committee and conducted in accordance with the Declaration of Helsinki and European laws on patient rights and data protection.

Patients ≥ 18 years with an increased stroke risk (i.e. CHA2DS2-VASc score ≥ 2) who received a pacemaker with both an atrial and ventricular lead were included in the HERO registry. Patients with a history of AF or atrial flutter (AFl) were excluded.

At Rijnstate Hospital, it is standard practice for pacemaker recipients to receive either a Biotronik (Berlin, Germany) or Boston Scientific (Marlborough, MA, USA) pacemaker. Between 1 January 2016 and 30 April 2018, patients receiving a Biotronik pacemaker were offered Biotronik’s RM device as part of this exploratory study. All eligible patients who received a pacemaker within this period were included, and those using remote monitoring (RM+) were compared with those not using remote monitoring (RM−).

Medical records of eligible patients were retrospectively assessed. The study follow-up period for each participant extended from the date of pacemaker implantation to the last follow-up date, ending on 7 August 2024. Patients were considered lost to follow-up if they were deceased, had discontinued follow-up at Rijnstate Hospital, had switched to AAI or VVI pacing mode, or had received a different device type or model.

The primary objective was to assess the difference in time to detection of the first arrhythmic event between the RM+ and RM− groups. The endpoint was measured as the time from pacemaker implantation to the first arrhythmic event, including all atrial and ventricular arrhythmias.

Secondary endpoints included the time to detection of the first device- or lead-related adverse events, the numbers of outpatient clinic visits and hospital admissions for all cardiac causes, and the number of patients for whom anticoagulation (including antiplatelet therapy) prescription was adjusted during follow-up. All changes in anticoagulation or antiplatelet therapy were included, not only changes in the context of arrhythmias.

Biotronik’s CardioMessenger device automatically gathers pacemaker data daily, provided the pacemaker is within range. All transmitted RM data can be reviewed by a physician via the Home Monitoring system on a secure website. When a (programmed) abnormality is detected, an alert is sent to the hospital, where it is reviewed daily by a pacemaker technician.

Alerts for arrhythmias were activated for all RM+ patients. When an atrial event exceeded 6 min, patients were contacted and asked whether they were experiencing symptoms. In cases of AHRE > 24 h or symptomatic atrial arrhythmias, anticoagulation was initiated in accordance with guidelines. Patients with subclinical AF were informed and invited to participate in either the ARTESIA or NOAH-AFNET 6 trial. Regarding ventricular arrhythmias, action was taken in cases of sustained ventricular tachycardia episodes (≥ 30 s) or recurrent non-sustained ventricular tachycardia.

As this is a retrospective study, all patients received standard care. Outpatient clinic visits were scheduled for 2 weeks and 2 months after implantation, followed by annual pacemaker readouts for both groups. Additional readouts were conducted if clinically indicated. Biotronik pacemaker recipients were offered the CardioMessenger device either at the 2‑week post-implantation visit or during the annual readout.

Continuous data were expressed as means ± standard deviation or medians (interquartile range), while categorical data were displayed as counts and percentages. Continuous variables were compared using an independent sample t-test or Mann-Whitney U test, as appropriate, and categorical variables were compared using Fisher’s exact test.

Cumulative incidence curves created by Kaplan-Meier analysis were used to visualise the time to the primary endpoint as well as time to the secondary endpoint, i.e. first lead- or device-related adverse event. Hazard ratios (HRs) with 95% confidence intervals (CIs) for the time differences between the two groups were calculated using a Cox proportional hazards model, adjusting for confounders if necessary.

The number of outpatient clinic visits and hospital admissions for all cardiac causes was calculated as events per patient-year per group. The proportions of patients with changes in anticoagulation prescriptions during follow-up were compared using Fisher’s exact test. Statistical analyses were performed using SPSS version 29.0.1.0 (IBM Corp., Armonk, NY, USA).