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Updated: Aug 6, 2026

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
Published on: December 11, 2017
Complete Left Bundle Branch Block Resolution After Cardiac Resynchronization Therapy With Serial Phonocardiographic
Kazuhiro Kamada1, Soh Kase1, Naoya Otaka1
1Department of Cardiovascular Medicine, Matsuyama Red Cross Hospital, Matsuyama, Ehime, Japan.
Insights
Cardiac resynchronization therapy (CRT) can reverse electrical abnormalities in heart failure patients. A case study shows resolution of complete left bundle branch block (CLBBB) and improved heart function after CRT.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Cardiac resynchronization therapy (CRT) is known to induce reverse remodeling in heart failure patients.
- Resolution of complete left bundle branch block (CLBBB) post-CRT is rare and infrequently documented with serial phonocardiography.
Background:
Cardiac resynchronization therapy (CRT) induces structural and electrical reverse remodeling in patients with heart failure. However, resolution of complete left bundle branch block (CLBBB) following CRT has rarely been described, particularly with serial phonocardiographic assessment.
Case Summary:
A 67-year-old man with heart failure associated with atrial fibrillation and CLBBB underwent CRT pacemaker implantation following pulsed-field ablation. Initially, the optimal interventricular (VV) delay required left ventricular pre-excitation, but shifted toward right ventricular pre-excitation after 1 month. Three months after CRT implantation, CLBBB resolved and left ventricular function nearly normalized. Phonocardiography demonstrated an increased peak-to-peak amplitude of the first heart sound and the disappearance of the third and fourth heart sounds.
Discussion:
This case illustrates progressive electrical reverse remodeling reflected by serial changes in optimal VV delay settings and phonocardiographic findings.
Take-Home Message:
Temporal changes in optimal VV delay settings may reflect recovery of intrinsic ventricular conduction after CRT.
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