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Conduction system pacing (CSP) has emerged as a more physiological alternative to right ventricular pacing and is also being used in selected cases for cardiac resynchronization therapy. His bundle pacing was first introduced over two decades ago and its use has risen over the last five years with the advent of tools which have facilitated implantation. Left bundle branch area pacing is more recent but its adoption is growing fast due to a wider target area and excellent electrical parameters. Nevertheless, as with any intervention, proper technique is a prerequisite for safe and effective delivery of therapy. This document aims to standardize the procedure and to provide a framework for physicians who wish to start CSP implantation, or who wish to improve their technique.

Conduction system pacing (CSP) has emerged as a more physiological alternative to right ventricular pacing and is also being used in selected cases for cardiac resynchronization therapy. His bundle pacing was first introduced over two decades ago and its use has risen over the last years with the advent of tools which have facilitated implantation. Left bundle branch area pacing is more recent but its adoption is growing fast due to a wider target area and excellent electrical parameters. Nevertheless, as with any intervention, proper technique is a prerequisite for safe and effective delivery of therapy. This document aims to standardize the procedure and to provide a framework for physicians who wish to start CSP implantation, or who wish to improve their technique. A synopsis is provided in this print edition of EP-Europace. The full document may be consulted online, and a ‘Key Messages’ App can be downloaded from the EHRA website.

Left bundle branch pacing (LBBP) involves direct capture of left bundle fibers by placing the lead deep inside the interventricular septum. Several studies have shown the feasibility and efficacy of LBBP as an alternative modality for cardiac resynchronization therapy (CRT). This paper describes approach for providing cost effective CRT with defibrillator (CRT-D) by LBBP and dual chamber implantable cardioverter defibrillator (ICD) which we label as LBBP optimized ICD (LOT-ICD). LBBP was performed using C315 sheath and 3830 Selectsecure lead in all patients by premature ventricular complex guided approach. In patients with complete correction of conduction system disease, IS-1 connector plug of the IS-1/DF-1 lead was capped and 3830 lead connected to the dual chamber ICD pulse-generator at RV-P/S port. LOT-ICD provided stable R-wave sensing for arrhythmia monitoring and resulted in cost-effective resynchronization therapy at reduced fluoroscopy duration and radiation dose.

Cardiac resynchronization therapy (CRT) using biventricular pacing has limited efficacy in patients with heart failure (HF) and right bundle branch block (RBBB). Left bundle branch area pacing (LBBAP) is a novel physiologic pacing option. OBJECTIVE The aim of the study was to assess the feasibility and outcomes of LBBAP in HF patients with RBBB and reduced left ventricular systolic function, and indication for CRT or ventricular pacing. METHODS LBBAP was attempted in patients with left ventricular ejection fraction (LVEF) = 5% increase in ejection fraction) to LBBAP were assessed. RESULTS LBBAP was attempted in 121 patients and successful in 107 (88%). Patient characteristics included age 74 +/- 12 years, female 25%, ischemic cardiomyopathy 49%, and ejection fraction 35% +/- 9%. QRS axis at baseline was normal in 24%, left axis 63%, right axis 13%. LBBAP threshold and R-wave amplitudes were 0.8 +/- 0.3 V@ 0.5 ms and 10 +/- 9 mV at implant and remained stable during mean follow-up of 13 +/- 8 months. LBBAP resulted in narrowing of QRS duration (156 +/- 20 ms to 150 +/- 24 ms (P = .01) with R-wave peak times in V-6 of 85 +/- 16 ms. LVEF improved from 35% +/- 9% to 43% +/- 12% (P,.01). Clinical and echocardiographic response was observed in 60% and 61% of patients, respectively. Female sex and reduction in QRS duration with LBBAP were predictive of echocardiographic response and super-response. CONCLUSION LBBAP is a feasible alternative to deliver CRT or physiologic ventricular pacing in patients with RBBB, HF, and LV dysfunction.

BACKGROUND Cardiac resynchronization therapy (CRT) using bi-ventricular pacing (BVP) is effective in patients with heart failure, left bundle branch block (LBBB), and reduced left ventricular function. Left bundle branch area pacing (LBBAP) has been reported as an alternative option for CRT. OBJECTIVE The purpose of this study was to assess the feasibility and outcomes of LBBAP in patients who failed conventional BVP because of coronary venous (CV) lead complications or who were nonresponders to BVP. METHODS At 16 international centers, LBBAP was attempted in patients with conventional CRT indication who failed BVP because of CV lead complications or lack of therapeutic response to BVP. Heart failure hospitalization (HFH) and death, echocardiographic outcomes, procedural data, pacing parameters, and lead complications including CV lead failure are reported. RESULTS LBBAP was successfully performed in 200 patients (CV lead failures 156; nonresponders 44) (age 68 +/- 11 years; female 35%; LBBB 55%; right ventricular pacing 23%; ischemic cardiomyopathy 28%; nonischemic cardiomyopathy 63%; left ventricular ejection fraction [LVEF]

Cardiac resynchronization therapy (CRT) with biventricular pacing (BVP) is well-established therapy in patients with reduced left ventricular ejection fraction (LVEF) and bundle branch block or indication for pacing. Conduction system pacing (CSP) using His-bundle pacing (HBP) or left bundle branch area pacing (LBBAP) has been shown to be a safe and more physiological alternative to BVP.The purpose of this study was to compare the clinical outcomes between CSP and BVP among patients undergoing CRT.This observational study included consecutive patients with LVEF ≤35% and class I or II indications for CRT who underwent successful BVP or CSP at 2 major health care systems. The primary outcome was the composite endpoint of time to death or heart failure hospitalization (HFH). Secondary outcomes included subgroup analysis in left bundle branch block as well as individual endpoints of death and HFH.A total of 477 patients (32% female) met inclusion criteria (BVP 219; CSP 258 [HBP 87, LBBAP 171]). Mean age was 72 ± 12 years, and mean LVEF was 26% ± 6%. Comorbidities included hypertension 70%, diabetes mellitus 45%, and coronary artery disease 52%. Paced QRS duration in CSP was significantly narrower than BVP (133 ± 21 ms vs 153 ± 24 ms; P.001). LVEF improved in both groups during mean follow-up of 27 ± 12 months and was greater after CSP compared to BVP (39.7% ± 13% vs 33.1% ± 12%; P.001). Primary outcome of death or HFH was significantly lower with CSP vs BVP (28.3% vs 38.4%; hazard ratio 1.52; 95% confidence interval 1.082-2.087; P = .013).CSP improved clinical outcomes compared to BVP in this large cohort of patients with indications for CRT.

Left bundle branch pacing (LBBP) provides electrical and mechanical synchrony at low and stable pacing output and effectively corrects distal conduction system disease. The criteria for differentiating LBBP from LV septal pacing has not been validated in large trials. There are several electrocardiography-based and intracardiac electrogram-based criteria to confirm LBB capture. In this section, the authors review these criteria and their overall accuracy.

Objectives This study aims to assess the safety and feasibility of achieving His-Purkinje conduction system pacing (HPCSP) in consecutive patients with atrioventricular block (AVB) and to describe the site of conduction block in patients with infranodal AVB. Background HPCSP has evolved as the preferred form of physiologic pacing. Left bundle branch area pacing (LBBAP) has emerged as an effective alternative to His bundle pacing (HBP). Methods Consecutive patients with AVB referred for pacemaker implantation were included in the study. HBP or LBBAP was attempted in all patients. Site of conduction block was identified as nodal or infranodal (intra-Hisian or infra-Hisian) AVB. Results HPCSP was attempted in 333 consecutive patients with AVB and was successful in 322 (97%) patients. HBP was achieved in 140 patients, LBBAP in 179 patients, and both in 3 patients. Site of conduction block was nodal in 55% and infranodal in 45% (intra-Hisian 89%; infra-Hisian 4%; indeterminate 7%). QRS duration at baseline was 111±27 versus 129±31 (P Conclusions HPCSP pacing was successfully performed in 97% of unselected patients with AVB irrespective of the site of conduction block. True infra-Hisian block (distal His-Purkinje conduction disease) is rare. HBP and LBBAP were complementary in achieving stable and low capture thresholds.

BackgroundTargets for right-sided conduction system pacing (CSP) include His bundle and right bundle branch. ECG patterns, diagnostic criteria and outcomes of right bundle branch pacing (RBBP) are not known.ObjectiveOur aims were to delineate electrocardiographic and electrophysiological characteristics of RBBP and to compare outcomes between RBBP and His bundle pacing (HBP).MethodsPatients with confirmed right CSP were divided according to the conduction system potential to QRS interval at the pacing lead implantation site. Six hypothesized RBBP criteria as well as pacing parameters, echocardiographic outcomes and all-cause mortality were analyzed.ResultsAll analyzed criteria discriminated between HBP and LBBP: double QRS transition during threshold test, selective paced QRS different from conducted QRS, stimulus to selective QRS > potential-QRS, small increase in V6RWPT during QRS transition, equal capture thresholds of CSP and myocardium, and stimulus-V6R-wave peak time (V6RWPT) > potential-V6RWPT (adopted as diagnostic standard). Per this last criterion, RBBP was observed in 19.2% (64/326) patients who had been targeted for HBP, present mainly among patients with potential to QRS < 35 ms (90.6%, 48/53) and occasionally in the remaining patients (5.6%, 16/273). RBBP was characterized by longer QRS (by 10.5 ms), longer V6RWPT (by 11.6 ms) and better sensing (by 2.6 mV) compared to HBP. During median follow-up of 29 months, no differences in capture threshold, echocardiographic outcomes or mortality were found.ConclusionsRBBP is a distinct CSP modality that is frequently observed when the pacing lead is positioned more distally along the right conduction system.

Objectives The aim of the study was to report the efficacy of left bundle branch pacing (LBBP) in the management of left bundle branch block (LBBB)-induced cardiomyopathy (LIC). Background...

Excessive prolongation of PR interval impairs coupling of AV contraction, which reduces left ventricular pre-load and stroke volume, and worsens symptoms. His-bundle pacing allows AV-delay shortening while maintaining normal ventricular activation. HOPE-HF evaluated whether AV-optimized His pacing is preferable to no-pacing, in double-blind cross-over fashion, in patients with heart failure, left ventricular ejection fraction (LVEF) ≤40%, PR interval ≥200ms and either QRS ≤140ms or right BBB.Patients had atrial and His-bundle leads implanted (and an ICD lead if clinically indicated) and were randomized, to 6-months of pacing and 6-months of no-pacing utilizing a cross-over design. The primary outcome was peak oxygen uptake during symptom-limited exercise. Quality of life, LVEF and patients' holistic symptomatic preference between arms were secondary outcomes. 167 patients were randomized: 90% men, 69±10 years, QRS duration 124±26ms, PR interval 249±59ms, LVEF 33±9%. Neither peak VOHis-bundle pacing did not increase peak oxygen uptake but, under double-blind conditions, significantly improved quality of life and was symptomatically preferred by the clear majority of patients. Ventricular pacing delivered via the His bundle did not adversely impact ventricular function during the 6 months. This article is protected by copyright. All rights reserved.

Atrioventricular node ablation (AVNA) with right ventricular or biventricular pacing (conventional pacing; CP) is an effective therapy for patients with refractory atrial fibrillation (AF). Conduction system pacing (CSP) using His bundle pacing or left bundle branch area pacing preserves ventricular synchrony.The aim of our study is to compare the clinical outcomes between CP and CSP in patients undergoing AVNA.Patients undergoing AVNA at Geisinger Health System between January 2015 and October 2020 were included in this retrospective observational study. CP or CSP was performed at the operators' discretion. Procedural, pacing parameters, and echocardiographic data were assessed. Primary outcome was the combined endpoint of time to death or heart failure hospitalization (HFH) and was analyzed using Cox proportional hazards. Secondary outcomes were individual outcomes of time to death and HFH.AVNA was performed in 223 patients (CSP, 110; CP, 113). Age was 75 ± 10 years, male 52%, hypertension 67%, diabetes 25%, coronary disease 40%, and left ventricular ejection fraction (LVEF) 43% ± 15%. QRS duration increased from 103 ± 30 ms to 124 ± 20 ms (CSP is a safe and effective option for pacing in patients with AF undergoing AVNA in high-volume centers.

A 61-years-old male underwent left bundle branch pacing for nonischemic dilated cardiomyopathy with recurrent heart failure. Left bundle branch pacing (LBBP) resulted in reduction in QRS duration along with improvement in left ventricular ejection fraction (LVEF) to 64% during follow-up. Two years after implantation he had recurrence of symptoms along with decline in LVEF to 51%. Late lead dislodgement was diagnosed and re-do LBBP was planned. The lead was extracted en-masse without complication and a new 3830 lead was positioned deep inside the proximal septum to capture the left bundle. Postprocedure echocardiography showed no ventricular septal defect or damage to tricuspid leaflet.

Left bundle branch area pacing (LBBAP) is a novel therapeutic option for bradycardia and heart failure patients. ECG belt is a novel technology for assessment of ventricular electrical heterogeneity (VEH) using multi-electrode ECG. A metric of overall VEH based on standard deviation of activation times (SDAT) from all electrodes in the ECG belt has been previously shown to predict cardiac resynchronization therapy (CRT) response. The aim of the study is to evaluate non-invasive assessment of VEH using ECG belt to optimize LBBAP.VEH from a 40-electrode ECG belt was characterized in 20 patients (male 15, EF 33 ± 13%, NYHA class 3.05 ± 0.6; CRT indication 18) during LBBAP (20) and LBBAP-Optimized CRT (LOT-CRT-7), anodal capture (16), NS-LBBP (18), S-LBBP (5), LVSP (9). In addition to SDAT, regional (LV/RV) VEH was assessed with average left ventricular activation times (LVAT), SDAT of left-sided (LV dispersion) and right-sided (RV dispersion) electrodes. Optimal LBBAP was determined based on maximal SDAT and QRS duration (d) change.All metrics were significantly reduced (p 0.0001 for ECG belt metrics, p = 0.0027 for QRSd) during LBBAP and LOT-CRT compared to intrinsic. QRSd, SDAT, LVAT, and LV and RV dispersion during optimal LBBAP were significantly lower (133 ± 20/157 ± 24; 20.5 ± 7.5/38.6 ± 9; 44.4 ± 14.3/61.4 ± 21; 11.6 ± 11.6/29.5 ± 15; 21.1 ± 7.8/42.5 ± 9.3; p 0.0001) compared to intrinsic rhythm. However, they were not significantly different among selective, non-selective, anodal, and LV septal captures. EF and NYHA class improved to 46 ± 11% and 1.9 ± 0.6 (p 0.001).LBBAP significantly reduced overall and regional (RV/LV) VEH, irrespective of the mechanism of capture. Detailed assessment of electrical heterogeneity using ECG belt may add valuable insights on effects of LBBAP.ClinicalTrials.gov Identifier: NCT04583709.