Pacing strategies for atrioventricular block: a comparison of leadless, his bundle, and right ventricular stimulation

Background/Objectives Right ventricular pacing (RVP), leadless pacing (LL), and conduction system pacing (CSP) are established treatment options for atrioventricular block (AVB), each offering unique features. However, comprehensive comparisons of their long-term outcomes remain limited. This study aims to assess the clinical and echocardiographic outcomes in patients with AVB treated with dual-chamber RVP, His bundle pacing (HBP), or leadless pacemakers with atrial mechanical tracking activity (VDD LL). Methods This single-center observational registry study enrolled 22 consecutive patients who received VDD LL pacing between October 2020 and October 2022. These patients were matched with 66 control patients—33 treated with RVP and 33 with HBP—using propensity score matching in a 2:3:3 ratio. The primary and secondary endpoints included all-cause mortality, cardiovascular mortality, heart failure, and echocardiographic outcomes. Additionally, atrioventricular synchrony in the VDD LL group was analyzed to stratify survival rates based on the percentage of atrial sensing. Results A total of 88 patients (30.7% female sex) with a mean age of 74.2 years were enrolled in the study. At two years, all-cause mortality was significantly higher in the VDD LL group compared to RVP (36.4% vs. 6.1%, p = 0.002) and HBP (36.4% vs. 12.1%, p = 0.03) (Figure 1). However, no significant differences were observed between the three groups in cardiovascular mortality and heart failure incidence. Despite propensity score matching, the VDD LL group presented a more severe clinical profile at baseline due to the specific situations dictating intravascular hardware minimization, especially advanced kidney disease in dialysis. At 1 year follow-up, patients receiving RVP showed a significant decrease in left ventricular ejection fraction and an increase in ventricular volumes. HBP patients exhibited favorable cardiac remodeling, while no significant echocardiographic changes were observed in the VDD LL group (Figure 2). Stratification based on atrial sensing showed that VDD LL patients with >66% AV synchrony had a lower mortality (p = 0.02). All three implantation techniques demonstrated very low rates of both periprocedural complications (3.4%) and late-onset complications (3.4%), with no significant differences between groups. Conclusions CSP provides superior outcomes compared to other pacing methods in terms of ventricular function, due to physiological ventricular activation and the preservation of AV synchrony. However, the elevated mortality observed among VDD LL recipients may be primarily attributed to non-cardiovascular causes rather than LV dysfunction. As a result, VDD LL pacing may be a viable alternative for specific patient groups, such as those requiring pacing less than 20% of the time or frail individuals at high risk of complications from transvenous implantation, as the suboptimal AV synchrony is traded off with lesser ventricular dyssynchrony.