Conduction System Pacing-Induced Ventricular Arrhythmia: Case Report

Authors, Journal, Affiliations, Type, DOI

• Authors: Serhat Kesriklioglu, Ahmet Taha Sahin, Mertcan Gezer, Mustafa Celik, Ahmet Lutfu Sertdemir, Enes Elvin Gul
• Journal: Annals of Noninvasive Electrocardiology 2026;31:e70190
• Affiliation: Department of Cardiology, School of Medicine, Necmettin Erbakan University, Konya, Türkiye
• Type: Case report
• DOI: 10.1111/anec.70190

Overview

This case report describes a 78-year-old woman with pacing-induced cardiomyopathy who underwent an upgrade from a dual-chamber pacemaker to LOT-CRT. LBBAP produced only deep septal pacing (DSP) with a prolonged V5 R-wave peak time, so a coronary sinus LV lead was added. The procedure acutely narrowed the paced QRS from 185 to 132 ms, but was accompanied by marked QT prolongation and T-wave inversions. On the first post-implant day she developed ventricular fibrillation triggered by premature ventricular complexes, without a reversible metabolic or ischaemic cause and with stable device parameters. She was treated with propranolol, remained arrhythmia-free for 10 days, and was not upgraded to an ICD because there were no further episodes. The report is a reminder that acute electrical resynchronisation does not guarantee electrical stability, and that early post-implant arrhythmic vulnerability may exist in severely remodelled ventricles.

Keywords

Arrhythmias; Cardiac resynchronization therapy; Case report; Left bundle branch area pacing; Ventricle

Key Takeaways

Case

• 78-year-old woman with a dual-chamber pacemaker implanted in 2020 for complete heart block; admitted for CRT upgrade because of progressive pacing-induced cardiomyopathy.
• NT-proBNP 19,032 pg/mL; LVEF 35%; severe mitral regurgitation; moderate tricuspid regurgitation.
• Baseline paced QRS 185 ms.
• LBBAP attempted with a Medtronic 3830 lumenless lead; multiple attempts achieved only deep septal pacing with V5 RWPT 104 ms.
• A coronary sinus LV lead was added (lateral branch) to complete LOT-CRT.
• Final paced QRS 132 ms with appropriate capture, but the ECG showed QT prolongation and T-wave inversions in precordial and inferior leads.
• Day 1 post-procedure: ventricular fibrillation requiring defibrillation.
• No reversible metabolic or ischaemic trigger; device interrogation showed appropriate sensing and capture, no lead dislodgement; echo showed no septal haematoma, no pericardial effusion, and no new regional wall motion abnormality.
• PVC morphology suggested the arrhythmia was triggered by the LBBAP lead rather than the LV lead.
• Propranolol 40 mg orally three times daily was started to shorten QT and suppress ventricular arrhythmia; other antiarrhythmics were avoided because of QT prolongation.
• No further arrhythmia during a 10-day hospital stay; ICD upgrade was not performed because there had been only one episode.

Discussion points

• LBBAP generally reduces transmural dispersion of repolarisation and has a lower proarrhythmic risk than BVP in the I-CLAS analysis, but proarrhythmia remains possible.
• Proposed mechanisms: shifts in depolarisation–repolarisation dynamics after restoration of synchrony; heterogeneous recovery of action potentials in remodeled myocardium; regional repolarisation dispersion from selective or partial fascicular capture.
• The early post-LBBAP period may be a window of increased arrhythmic vulnerability in severely compromised ventricles, independent of procedural success.
• Prior case reports cited: bundle branch re-entrant VT during LBBAP implantation (Ponnusamy and Vijayaraman 2021); monomorphic VT months after LBBP (Tanawuttiwat 2023); electrical storm with fascicular-like PVCs resolving after lead removal (Bhatt 2024); delayed septal perforation causing VT (Hsieh 2024).

Limitations of the document

• Single case report — no control group, no incidence estimate, and no ability to establish causality.
• Attribution of the arrhythmia to LBBAP is inferential, based on PVC morphology; the LV lead, the underlying cardiomyopathy, and the procedure itself cannot be excluded as contributors.
• No electrophysiological study or mapping was performed to confirm the arrhythmia mechanism.
• Short follow-up (10 days) — late recurrence and the appropriateness of withholding an ICD are unknown.
• QT prolongation and T-wave inversion are described but not quantified (no QTc values), limiting mechanistic interpretation.
• No genetic or fibrosis characterisation to explain individual susceptibility.
• Consent and publication: written informed consent obtained; authors report no conflicts of interest.

Key Concepts Mentioned

• concepts/Conduction-System-Pacing — the broader technique
• concepts/Left-Bundle-Branch-Area-Pacing — the pacing strategy
• concepts/LOT-CRT — the hybrid configuration used
• concepts/Pacing-Induced-Cardiomyopathy — the indication for upgrade
• concepts/Sudden-Cardiac-Death — the adverse event

Key Entities Mentioned

• Necmettin Erbakan University (Konya) — the reporting centre
• Medtronic — manufacturer of the 3830 lead

Wiki Pages Updated

• Created: wiki/sources/lot-crt-vt-ane-2026.md
• Updated: wiki/concepts/Conduction-System-Pacing.md (Contradictions / Open Questions)
• Updated: wiki/concepts/LOT-CRT.md
• Updated: wiki/concepts/Pacing-Induced-Cardiomyopathy.md
• Updated: wiki/sourceindex.md
• Updated: log.md