CUSUM Analysis as a Predictive Tool for the Learning Curve in Left Bundle Branch Area Pacing

Sep 30, 2026

Left bundle branch area pacing (LBBAP) has emerged as a physiological alternative to conventional pacing, yet the learning curve for new operators is insufficiently characterized. This single-center, single-operator retrospective study analyzed 108 consecutive LBBAP attempts by a first-time operator without prior conduction system pacing experience. Fluoroscopy time served as the primary metric, using predefined targets to classify success or failure and CUSUM plots to locate the proficiency inflection point. Results showed decreasing fluoroscopy time, with an inflection after ~65 non-CRT cases and stable safety and electrical outcomes across learning.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages14

Reading Time35 min

AccessFree to download

Abstract

Background/Objectives

Methods

Results

Conclusions

1. Introduction

2. Materials and Methods

2.1. Study Design and Setting

Article CUSUM Analysis as a Predictive Tool for the Learning Curve in Left Bundle Branch Area Pacing Ionu Tudorancea 1,2, Mihai S, tefan Cristian Haba 1,2,*, Mircea Cristian Placinta 1, Irene Paula Popa 1, Emil Gabriel Calistrat 2, Alexandru Guila 2, Daniela Cris, u 2, Viviana Onofrei 1,2, Dragomir Nicolae S, erban 1, Ionela Lăcrămioara S, erban 1, Radu Iliescu 1,3 and Irina Iuliana Costache Enache 1,2 Academic Editor: Axel Brandes Received: 16 November 2025 Revised: 11 December 2025 Accepted: 20 December 2025 Published: 1 January 2026 Copyright: © 2026 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license. 1 Grigore T. Popa University of Medicine and Pharmacy, 700115 Iasi, Romania; ionut.tudorancea@umfiasi.ro (I.T.); irene-paula_popa@umfiasi.ro (I.P.P.); irina.costache@umfiasi.ro (I.I.C.E.) 2 Cardiology Clinic,“Saint Spiridon” County Clinical Emergency Hospital, 700111 Iasi, Romania 3 Transcend Research Centre, 2-4 General Henri Mathias Berthelot Street, 700483 Ia¸si, Romania * [Correspondence: mihai.haba@umfiasi.ro](Correspondence: mihai.haba@umfiasi.ro) Abstract Background/Objectives: Left bundle branch area pacing (LBBAP) has rapidly emerged as a physiological alternative to conventional pacing. However, the learning curve for new operators remains poorly characterized. We aimed to describe the learning curve of LBBAP using cumulative sum (CUSUM) analysis in a single-center, single-operator setting. Methods: We conducted a retrospective analysis of 108 consecutive LBBAP attempts performed by a first-time operator with no prior conduction system pacing experience. Fluoroscopy time was selected as the primary performance metric. A predefined procedural target (≤6 min for non-CRT and ≤9 min for CRT implants) was used to classify each case asa success or failure. CUSUM plots were generated to identify the inflection point marking proficiency acquisition. Results: In non-CRT cases (n = 95), fluoroscopy time progressively decreased, and the CUSUM curve showed a distinct inflection after approximately 65 cases, indicating the attainment of procedural proficiency. In CRT implants (n = 9), acceptable fluoroscopy exposure was achieved soon after the non-CRT proficiency threshold was reached. Electrical performance and safety outcomes remained stable throughout the learning process. Conclusions: CUSUM provides a clear, objective, and real-time measure of operator progression during the initial learning phase of LBBAP. The technique reliably identified the proficiency transition and can be readily implemented for procedural training, credentialing, and competency monitoring in centers adopting LBBAP. Keywords: left bundle branch pacing; conduction system pacing; cumulative sum (CUSUM) analysis; learning curve; operator training; cardiac resynchronization therapy 1. Introduction Cardiac conduction disorders are a major cause of morbidity, for which permanent pacemaker implantation remains the standard therapy in patients with symptomatic bradycardia. Traditionally, right ventricular apical pacing (RVAP) has been the standard approach; however, the electrical and mechanical dyssynchrony associated with RVAP increases the risk of atrial fibrillation, heart failure, and overall mortality [1–5] . Alternative pacing sites, such as the right ventricular septum and outflow tract, have not consistently yielded superior long-term outcomes [6,7] . Left bundle branch pacing (LBBP) has recently emerged as a promising physiological pacing technique. By directly stimulating the left conduction system distal to the His bundle, LBBP enables synchronous ventricular activation. Multiple studies have demonstrated its efficacy in both bradycardia and resynchronization indications, with improved electrical synchrony and favorable clinical outcomes compared with conventional pacing [8–14

FAQs

What is the main goal of the study?

To describe the learning curve of left bundle branch area pacing (LBBAP) using cumulative sum (CUSUM) analysis and to identify the proficiency transition point.

How was operator proficiency measured?

Fluoroscopy time was used as the primary performance metric, with predefined procedural targets classifying each case as success or failure and CUSUM plots identifying an inflection point.

What did the CUSUM analysis show in non-CRT and CRT cases?

In non-CRT cases, fluoroscopy time progressively decreased and the CUSUM curve showed a clear inflection after approximately 65 cases. In CRT implants, acceptable fluoroscopy exposure was reached shortly after the non-CRT proficiency threshold.

Sep 30, 2026

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