Key result
Delta increments in pacing QRS duration ≥43 msec in pre-existing RBBB (HR 2.91) and ≥33 msec in LBBB (HR 11.44) independently predicted cardiovascular mortality in pacemaker recipients.
Why the study?
The clinical implication of pre-existing intraventricular conduction disturbance in permanent pacemaker recipients was unknown.
Does the delta increment in pacing QRS duration predict cardiovascular mortality in patients with pre-existing bundle branch block receiving permanent pacemakers?
Cohort (n=1,424)
Does the delta increment in pacing QRS duration predict cardiovascular mortality in patients with pre-existing bundle branch block receiving permanent pacemakers?
Hazard Ratio: 1.01 (95% CI 1–1.04)
p-value: p=0.038
In permanent pacemaker recipients with pre-existing bundle branch block, a larger delta increment in pacing QRS duration is a strong independent predictor of cardiovascular mortality.
Larger QRS prolongation with pacing may flag higher CV mortality risk in BBB patients; leaves open whether QRS-optimized lead placement improves survival.
Background: The clinical implication of pre-existing intraventricular conduction disturbance (IVCD) in permanent pacemaker (PPM) recipients is unknown. Objectives: To explore the clinical outcomes in patients with pre-existing IVCD after implantation of PPMs. Methods: A total of 1424 patients who received PPMs were categorized into three groups by pre-procedural electrocardiography: patients without IVCD (n = 1045), patients with right bundle branch block (RBBB) (n = 309), and patients with left bundle branch block (LBBB) (n = 70). The primary outcome was cardiovascular (CV) mortality. Receiver operating characteristic curve analysis was performed to determine the optimal cut-off values of variable in predicting CV mortality. Results: During follow-up, there was no significant difference in CV mortality between patients with and without IVCD. In multivariate analysis, independent predictors of CV mortality were age [hazard ratio (HR): 1.03; 95% confidence interval (95% CI): 1.00-1.05; p = 0.026], history of heart failure [HR: 1.98; 95% CI: 1.19-3.29; p = 0.009], chronic kidney disease [HR: 1.75; 95% CI: 1.11-2.74; p = 0.015] and increment in pacing QRS duration [HR: 1.01; 95% CI: 1.00-1.04; p = 0.038]. Delta increments in pacing QRS duration ≥ 43 msec [HR: 2.91; 95% CI: 1.23-6.83; p = 0.014] in patients with pre-existing RBBB, and ≥ 33 msec [HR: 11.44; 95% CI: 2.03-64.30; p = 0.006] in patients with pre-existing LBBB were independent determinants of CV mortality. Conclusions: There was no difference in CV mortality between patients with or without IVCD. However, wider pacing QRS duration increased the risk of CV mortality in PPM recipients, and delta increment in pacing QRS duration increased the risk of CV mortality in patients with pre-existing IVCD.
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Chen et al. (2022) conducted a cohort in Pre-existing intraventricular conduction disturbance (IVCD) in permanent pacemaker recipients (n=1,424). Delta increment in pacing QRS duration vs. Smaller QRS increment or no IVCD was evaluated on Cardiovascular (CV) mortality (HR 1.01, 95% CI 1.00-1.04, p=0.038). Delta increments in pacing QRS duration ≥43 msec in pre-existing RBBB (HR 2.91) and ≥33 msec in LBBB (HR 11.44) independently predicted cardiovascular mortality in pacemaker recipients.
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