Half of all pacemakers implanted have a significant right ventricular pacing burden in the first year after pacing. Insights from remote monitoring

Identifying patients who are likely to pace is important for device selection, particularly in patients with impaired left ventricular function. Most studies report mean right ventricular pacing (RVP) from the previous clinic visit, which may not reflect its dynamic behaviour. RVP may be highly variable due to intermittent conduction disease, algorithms to minimise RVP, and paroxysmal arrhythmias. Remote monitoring (RM) overcomes this by providing a daily RVP percentage.

To evaluate right ventricular pacing behaviour during the first year of implant in pacemaker patients and discover whether an aggregated RVP percentage reflects the day-to-day behaviour of RVP using daily RM.

Daily RM data were retrieved in November 2023 for all bradycardia pacemaker patients under follow-up at our centre. The first year of RM data was analysed. Patients were grouped into deciles based on mean annual RVP. Variability of RVP was categorised by calculating a coefficient of variation (CoV) (standard deviation/mean) for RVP in each patient. Patients with i) a CoV of <30% or ii) mean RVP <1.5% were categorised as consistent, and those with a CoV of >30% as variable.

Complete RM data were available from implant for 899/1159 (77.6%). Significant mean annual RVP >20% was seen in 445 (49.5%). RVP burden in the first year following implant demonstrates a bimodal distribution, with most patients consistently pacing <10% (356, 40.0%) or >90% 242 (26.2%) (Figure 1). Patients in the <10% RVP decile paced very little at 1.5±2.2%. Only 2 (0.2%) patients consistently paced 11-20% whereas 52 (5.8%) patients have variable pacing at this level (p=<0.001). Of these, 16/52 (18%) spend at least 30% of their time pacing >20%, despite a mean RVP over the year of <20% (Figure 2.) Of those implanted for sinus node disease (SND), 15.8% had significant RVP (>20%) in the first year. Similarly, in those with complete heart block (CHB), 25.7% paced <20% in the first year. A third (19.9%) of patients with syncope and bifasicular/trifasicular block had significant RVP (>20%) during their first year of implant.

Half of patients in this pacemaker population had RVP >20% and these are the patients who may benefit from conduction system pacing. However, device indication of SND and CHB would wrongly predict RVP in 1 in 5 cases. Of those with pacing below the safe reported threshold of 20%, 1 in 5 spend a significant proportion pacing >20%. Consistently pacing at 11-20% is very rare and may explain why patients are rarely seen to get pacing induced cardiomyopathy at this level of pacing.Figure 1  Figure 2