Conduction system pacing (CSP) is being increasingly adopted as a more physiological alternative to right ventricular and biventricular pacing. Since the 2021 European Society of Cardiology pacing guidelines, there has been growing evidence that this therapy is safe and effective. Furthermore, left bundle branch area pacing was not covered in these guidelines due to limited evidence at that time. This Clinical Consensus Statement provides advice on indications for CSP, taking into account the significant evolution in this domain.

• Keywords
• Biventricular pacing, Cardiac resynchronization therapy, Conduction system pacing, His bundle pacing, Indications, Left bundle branch area pacing,
• MeSH
• Action Potentials MeSH
• Cardiology * standards   MeSH
• Cardiac Pacing, Artificial * standards   adverse effects   methods   MeSH
• Consensus MeSH
• Humans MeSH
• Heart Conduction System * physiopathology   MeSH
• Societies, Medical MeSH
• Arrhythmias, Cardiac * therapy   physiopathology   diagnosis   MeSH
• Heart Rate MeSH
• Treatment Outcome MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Practice Guideline MeSH
• Geographicals
• Europe MeSH

INTRODUCTION: Left bundle branch area pacing (LBBAP) comprises pacing at the left ventricular septum (LVSP) or left bundle branch (LBBP). The aim of the present study was to investigate the differences in ventricular electrical heterogeneity between LVSP, LBBP, right ventricular pacing (RVP) and intrinsic conduction with different dyssynchrony measures using the ECG, vectorcardiograpy, ECG belt, and Ultrahigh frequency (UHF-)ECG. METHODS: Thirty-seven patients with a pacemaker indication for bradycardia or cardiac resynchronization therapy underwent LBBAP implantation. ECG, vectorcardiogram, ECG belt and UHF-ECG signals were recorded during RVP, LVSP and LBBP, and intrinsic activation. QRS duration (QRSd) was measured from the ECG, QRS area was calculated from the vectorcardiogram, LV activation time (LVAT) and standard deviation of activation time (SDAT) from ECG belt and electrical dyssynchrony (e-DYS16) from UHF-ECG. RESULTS: Both LVSP and LBBP significantly reduced ventricular electrical heterogeneity as compared to underlying LBBB and RV pacing in terms of QRS area (p < .001), SDAT (p < .001), LVAT (p < .001) and e-DYS16 (p < .001). QRSd was only reduced as compared to RV pacing(p < .001). QRS area was similar during LBBP and normal intrinsic conduction, e-DYS16 was similar during LVSP and normal intrinsic conduction, whereas SDAT was similar for LVSP, LBBP and normal intrinsic conduction. For all these variables there was no significant difference between LVSP and LBBP. CONCLUSION: Both LVSP and LBBP resulted in a more synchronous LV activation than LBBB and RVP. Especially LBBP resulted in levels of LV synchrony comparable to normal intrinsic conduction.

• Keywords
• bradycardia pacing, cardiac resynchronization therapy, conduction system pacing, dyssynchrony, left bundle branch area pacing,
• MeSH
• Action Potentials * MeSH
• Bundle-Branch Block physiopathology   therapy   diagnosis   MeSH
• Bradycardia physiopathology   therapy   diagnosis   MeSH
• Time Factors MeSH
• Electrophysiologic Techniques, Cardiac MeSH
• Electrocardiography MeSH
• Ventricular Function, Left * MeSH
• Bundle of His * physiopathology   MeSH
• Cardiac Pacing, Artificial * MeSH
• Middle Aged MeSH
• Humans MeSH
• Ventricular Septum * physiopathology   MeSH
• Predictive Value of Tests * MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Heart Rate * MeSH
• Cardiac Resynchronization Therapy MeSH
• Vectorcardiography * methods   MeSH
• Treatment Outcome MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Comparative Study MeSH

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• MeSH
• Electrocardiography MeSH
• Ventricular Function, Left MeSH
• Bundle of His MeSH
• Cardiac Pacing, Artificial MeSH
• Humans MeSH
• Heart Conduction System * MeSH
• Heart Ventricles diagnostic imaging   MeSH
• Cardiac Resynchronization Therapy * MeSH
• Treatment Outcome MeSH
• Check Tag
• Humans MeSH
• Publication type
• Comment MeSH
• Editorial MeSH