Comparative clinical outcomes of conduction system pacing vs. right ventricular septal and apical pacing in patients with high ventricular pacing burden
D Martinez, T Santos, I Cruz, M Primo, A Ventura, J Ferreira, E Jorge, L GoncalvesAbstract
Background/Introduction
Conduction system pacing (CSP) offers a physiological pacing strategy for symptomatic bradycardia and cardiac resynchronization therapy. However, there is a lack of comparative studies analyzing medium-term outcomes of CSP versus different modalities of right ventricular pacing (RVP), particularly in patients with significant ventricular pacing burden, which can lead to pacing-induced cardiomyopathy (PICM) and affect overall health outcomes.
Purpose
To evaluate medium-term clinical outcomes of CSP compared to RVP modalities, with implications for treatment strategies in patients requiring frequent ventricular pacing.
Methods
This prospective single-center observational registry included consecutive patients undergoing pacemaker implantation from January 2023 to January 2025, all with a ventricular pacing burden > 40% during follow-up. The primary outcome was a composite of PICM or emergency room (ER) visits for acute heart failure (AHF), with secondary endpoints assessing each outcome individually. Multivariable Cox proportional hazards models estimated risks for ER visits due to AHF.
Results
A total of 740 patients were analyzed: 228 treated with CSP, 303 with septal pacing and 209 with apical pacing. CSP patients were significantly younger (77 [IQR 69-82] vs. 81 [IQR 75-86] years; p<0.001) and predominantly male (74% vs. 65%; p=0.023). Median follow-up was shorter for CSP (459 [IQR 188-681] days) versus RVP (760 [IQR 417-1,013] days). Compared with septal and apical pacing, CSP achieved a narrower paced QRS (mean 119±16 vs 152±19 vs 166±20 ms, respectively; p<0.001) and in patients with QRS>120 ms, more frequent QRS shortening (93% vs 35% vs 7%, respectively; p<0.001), with lower mean delta QRS (-18±30 vs 22±27 vs 40±27 ms, respectively; p<0.001). The primary outcome was less frequent in patients treated with CSP, compared with septal and apical pacing (12% vs 44% vs 61%, respectively; p<0.001), as well as PICM (5% vs 25% vs 35%, respectively; p<0.001) and ER visit for AHF (2.6% vs 10.6% vs 20.1%, respectively; p<0.001). Adjusted Cox model demonstrates CSP as a robust predictor of reduced ER visit for AHF (adjusted HR 0.183, 95% CI 0.072-0.463; p<0.001) and to a lesser extent septal pacing (adjusted HR 0.492, 95% CI 0.270-0.897; p=0.021) when compared to apical pacing (figure 1).
Conclusion(s)
In this cohort of patients with high ventricular pacing burden, CSP provided substantial medium-term clinical benefits when compared to right ventricular septal and apical pacing. These findings support physiological pacing strategies for patients expected to require frequent ventricular pacing.Adjusted Cox model for ER visits for AHFFor image description, please refer to the figure legend and surrounding text.