Impact of right ventricular pacing burden on shocks in patients with implantable cardioverter defibrillators
H Iwakawa, M Middeldorp, A Puvrez, S Kakarla, J Shroff, T Baykaner, E Fu, A Kroman, J Freeman, A Russo, T Deering, S Mittal, B Donovan, R Leahy, P SandersAbstract
Background
High burden of right ventricular pacing (RVP) may have a proarrhythmic effect in patients with implantable cardioverter defibrillators (ICDs).
Purpose
To assess how increased RVP burden impacts the incidence of shocks in ICD patients using a large real-world registry.
Methods
In a multicentre retrospective study utilizing a vendor-neutral remote monitoring (RM) platform, we included ICD patients with data on RVP burden and the date of shock delivery from January 2015 to November 2025. Patients with cardiac resynchronization therapy were excluded. The RVP burden (%RVP) for each patient was extracted from the initial transmission via a vendor-neutral remote monitoring platform. Regular RM logs recorded the date of each shock delivered.
Results
Among 36,528 patients with ICDs, the mean age was 63±13 years, and 30.2% were female. The total number of transmissions was 873,997, with a median of 15 per patient [7–29]. The median %RVP was estimated at 0.07% [0.00–1.00%], and the mean left ventricular ejection fraction was 40±15%. During a median follow-up of 3.9 [1.75–6.44] years, 4835 (13.2%) patients received shocks. Of these, 76.0% received anti-tachycardia pacing before the initial shock therapy. Multivariable Cox proportional hazards models were constructed, adjusting for age, sex, HF, and single- or dual-chamber device. Hazard ratios (HRs) for the initial shock occurrence in %RVP increase with %RVP up to 80% relative to %RVP < 1% (1-5%, HR 1.40 [1.30–1.52]; 5-10%, HR 1.32 [1.10–1.59]; 10-40%, HR 1.36 [1.18–1.58]; 40-80%, HR 1.35 [1.10–1.65]). By contrast, in ICD patients with very high RVP dependence (≥ 95%), the HR drops compared to those with %RVP < 1% (HR 0.71 [0.55–0.90]) (Figure).
Conclusions
Increased RVP burden was associated with a higher shock rate in patients with ICDs, whereas extremely high RVP dependence was not. These results suggest that a mixed intrinsic and paced ventricular rhythm may be associated with an increased risk of shock.Figure