Comparison of Pacing Performance and Clinical Outcomes Between Left Bundle Branch and His Bundle Pacing

BACKGROUND

Left bundle branch (LBBP) and His-bundle pacing (HBP) provide physiological ventricular activation.

OBJECTIVES

This study investigated differences in feasibility, device performance, and clinical outcomes between LBBP and HBP.

METHODS

Consecutive patients with LBBP and HBP from 2018 to 2021 in 2 centers were prospectively studied. The primary endpoint was optimal device performance during follow-up, defined as the presence of pacing thresholds <2.5 V, R-wave amplitude ≥5 V, and absence of conduction system pacing (CSP)-related complications. The secondary endpoint was the composite of heart failure hospitalizations or all-cause mortality.

RESULTS

Among 338 patients, 282 underwent successful CSP (119 HBP, 163 LBBP). Success rates, CSP-related complications, and need for reoperations did not differ between LBBP and HBP (P > 0.05). Pacing thresholds were lower, whereas R-wave amplitudes and lead impedance were higher in LBBP (P < 0.05). The primary endpoint was more frequent in LBBP than HBP (79% vs 34%; P < 0.001), with LBBP independently associated with 9-fold increased odds of optimal device performance (adjusted OR: 9.31; 95% CI: 5.14-16.86). LBBP was less likely to have increased pacing thresholds by >1 V (1% vs 19% HBP, P < 0.001). The secondary outcome was less frequent in LBBP than HBP (9% vs 24%, P = 0.001), with LBBP trending towards higher event-free survival (HR: 0.62; 95% CI: 0.31-1.23). The secondary outcome was independent of pacing burden or pacing indication.

CONCLUSIONS

Despite similar feasibility and safety profiles, LBBP confers additional benefits in pacing performance and reliability, shows trends towards improved survival compared to HBP, and should be the preferred first-line CSP modality of choice.

Acute procedural outcomes of his bundle pacing with or without electrophysiology mapping system: a multicenter study

Funding Acknowledgements

Type of funding sources: None.

Introduction

His bundle pacing (HBP) is associated with improved clinical outcomes compared to right ventricular apical pacing. However, it can be technically challenging and may result in prolonged fluoroscopy and procedural time.

Purpose

We sought to compare the feasibility of performing HBP with or without electrophysiology mapping (EP) system, focusing on evaluating acute procedural success, complication rates and short-term outcomes.

Methods

HBP patients at 3 hospitals were recruited between August 2018 to December 2020. HBP was performed with EP mapping system in 1 center, and without EP mapping in the other 2 centers. Acute procedural success was defined as either selective or non-selective His bundle capture with a threshold of less than or equal to 1.5V at 1ms at the end of procedure implantation.

Results

A total of 233 patients were recruited, of which HBP was performed with EP mapping in 77 patients (33.0%) and without EP mapping in 156 patients (67.0%). Both groups were similar in age (73.2 ± 11.0 years vs 75.3 ± 9.5 years, p = 0.125) and male sex (58.4% vs 48.1%, p = 0.136). There were more patients with ischemic heart disease (45.5% vs 22.4%, p &lt; 0.01) and reduced left ventricular ejection fraction ≤ 40% (28.6% vs 10.9%, p &lt; 0.01) in the group with EP mapping. The indications for HBP was for high-grade atrioventricular block (55.8%), sick sinus syndrome (35.6%) and cardiac resynchronization therapy (CRT) (8.6%). There were more patients who required CRT in the center with EP mapping (18.2% vs 3.8%, p &lt; 0.01). HBP was successful in 39 patients (50.6%) with EP mapping and 93 patients (59.6%) without EP mapping (p= 0.382). The median R wave at implant was similar in both groups [4.0 (2.9 – 6.2) mV vs 4.3 (4.3 – 7.0) mV, p = 0.808]. Impedance at implant (607 ± 195 ohms vs 547 ± 166 ohms, p &lt; 0.01) and selective His bundle bipolar threshold at implant [1.25 (0.75-1.75) V vs 0.7 (0.5 – 1.25) V, p = 0.01] was higher in patients with EP mapping while non-selective His bundle bipolar threshold at implant [1.75 (1.0 – 3.0) V vs 1.5 (0.9 – 2.2) V, p = 0.133] and paced QRS duration (116.4 ± 25.4 ms vs 114.4 ± 24.2 ms, p =0.655) were similar. There were no differences in procedural or fluoroscopy time between groups (111 ± 36.9 min vs 107 ± 40.7 min, p = 0.479; and 10.3 ± 8.9 min vs 12.1± 14.0 min, p = 0.328 respectively). There was a similar rate of acute procedural complications (5.2% vs 1.3%, p = 0.076) and patients requiring wound or lead revision (6.8% vs 1.9%, p = 0.115) after a median follow up duration of 205 days (67-397). The prevalence of new onset paroxysmal atrial fibrillation  (11.7% vs 4.2%, p = 0.037) and all cause mortality (12.3% vs 3.2%, p = 0.029) was increased in patients who underwent HBP with EP mapping.

Conclusion

HBP in centers with or without EP mapping showed similar acute procedure success and complication rates. The use of EP mapping system was not shown to affect procedural or fluoroscopy duration.

Lattice protein folding with two and four-body statistical potentials

The cooperative folding of proteins implies a description by multibody potentials. Such multibody potentials can be generalized from common two-body statistical potentials through a relation to probability distributions of residue clusters via the Boltzmann condition. In this exploratory study, we compare a four-body statistical potential, defined by the Delaunay tessellation of protein structures, to the Miyazawa-Jernigan (MJ) potential for protein structure prediction, using a lattice chain growth algorithm. We use the four-body potential as a discriminatory function for conformational ensembles generated with the MJ potential and examine performance on a set of 22 proteins of 30-76 residues in length. We find that the four-body potential yields comparable results to the two-body MJ potential, namely, an average coordinate root-mean-square deviation (cRMSD) value of 8 A for the lowest energy configurations of all-alpha proteins, and somewhat poorer cRMSD values for other protein classes. For both two and four-body potentials, superpositions of some predicted and native structures show a rough overall agreement. Formulating the four-body potential using larger data sets and direct, but costly, generation of conformational ensembles with multibody potentials may offer further improvements. Proteins 2001;43:161-174.