Six transition patterns and seven capture types in different left bundle branch bipolar pacing configurations.

Aims: This study aims to explore the different transition patterns and capture types during two bipolar pacing tests based on the selective left bundle branch (LBB) capture determined by the continuous pacing and recording technique. Methods: In total, 67 patients completed two unipolar and two bipolar pacing tests based on selective LBB capture during screwing-in for left bundle branch pacing (LBBP) using the continuous pacing and recording technique. The electrophysiological characteristics and potential mechanisms of different pacing configurations were further evaluated in this study. Results: We found six transition patterns and derived seven capture types in two bipolar pacing tests according to the analysis of continuous electrocardiogram and electrogram changes. Compared with the conventional configuration of "Tip-Ring+" bipolar pacing, "Ring-Tip+" testing had a lower threshold for simultaneous capture of the LBB and the left and right ventricular septum myocardium (1.57 vs. 2.84 V at 0.5 ms) and was the only configuration to yield the peculiar "LBBP + right ventricular septum pacing (RVSP)" capture type. Conclusions: In this study, we observed for the first time that "Ring-Tip+" bipolar pacing allows for a lower clinically applicable pacing threshold for simultaneous capture of the LBB and left and right ventricular septum myocardium, and the peculiar "LBBP + RVSP" capture type. This may be a more advantageous physiological pacing configuration, warranting further investigation and application in the future. Lay summary: Based on the specific selective LBB capture, we first found six transition patterns and derived seven capture types in two bipolar pacing tests due to the different thresholds of the LBB, left ventricular septal myocardial, and right ventricular septal myocardial. Compared with the conventional configuration of "Tip-Ring+" bipolar pacing, "Ring-Tip+" testing had a lower threshold for simultaneous capture of the LBB and the left and right ventricular septum myocardium (1.57 vs. 2.84 V at 0.5 ms) and was the only configuration to yield the peculiar "LBBP + RVSP" capture type. More pacing strategies should be released and investigated to achieve the best physiological pacing according to the individualized electrophysiological characteristics of patients.

Left bundle branch pacing guide by uninterrupted recording of intrinsic filtered and unfiltered intracardiac electrograms.

BACKGROUND: Currently, the interrupted recording technique is commonly used to perform left bundle branch (LBB) pacing (LBBP). However, this method requires repeated testing to confirm that the LBB is captured and perforations are avoided. An automated solution may make this repetitive work easier. CASE SUMMARY: LBBP was performed using an uninterrupted recording technique in an 86-year-old woman. Lead position and LBB capture was confirmed by the characteristics of the intrinsic filtered and unfiltered intracardiac electrograms. CONCLUSION: Continuous mapping and recording technique may help achieve more accurate positioning of LBBP lead in the ventricular septum.

His potential injury as the end point of screwing by a continuous recording technique in His bundle pacing: A case report.

BACKGROUND: His bundle pacing (HBP) engaged electrical activation of both ventricles by stimulating the His-Purkinje network, which could avoid marked ventricles dyssynchrony. The lead was given three to five clockwise rotations at the site with the His potential to anchor the interventricular septum. In 2018, the Multicenter His Bundle Pacing Collaborative Working Group recommended that the His bundle capture threshold should be lower than 2.5 V/1 ms in non-pacing-dependent patients, and pacing-dependent patients should have a lower adjacent ventricular capture threshold as self-backup. Therefore, to avoid safety issues such as loss of capture caused by increased threshold, we believe that more stringent criteria should be adopted in patients with atrioventricular block (AVB). In previous studies, the connection cable needed to be disconnected during the screwing. When the procedure was finished, the performer found that the patients with His bundle injury could obtain a lower threshold than those without His bundle injury. Although no studies of new bundle branch block (BBB) or AVB by the acute His bundle injury was reported. However, It is worrying that the damage of His bundle seems random during the procedure. How to balance avoiding severe injury with a lower capture threshold? At present, we report a case of light His injury and lower His capture threshold under continuous intracardiac electrocardiogram monitoring.

An interesting dynamic retrograde His bundle potential during the transventricular-septal process for left bundle branch pacing in a patient with right bundle branch block: A case report.

A 67-year-old male presented with symptomatic bradycardia caused by atrial fibrillation and underwent His bundle pacing (HBP) and left bundle branch pacing (LBBP). Electrocardiography (ECG) revealed a complete right bundle branch block (RBBB). John Jiang's connecting cable was used during the transventricular septal process. An interesting dynamic retrograde His bundle potential (RHP) was recorded with uninterrupted lead screws.

A shorter R wave peak time in left bundle branch pacing may not be a marker of more physiological ventricular activation: A case report.

Left bundle branch pacing (LBBp) is a promising alternative to conventional biventricular pacing cardiac resynchronization therapy. The left anterior fascicle (LAF) is adjacent to the left ventricular outflow tract, while the left posterior fascicle (LPF) dominates a broader area of the left ventricle. Whether LAF or LPF dominates ventricular activation has not been determined. We present the case of a 76-year-old man who underwent LBBp implantation and propose the left ventricular activation domination in LPF pacing, an alternative when LBBp is unavailable.

Corrigendum: Guidance on left bundle branch pacing using continuous pacing technique and changes in lead V1 characteristics under real-time monitoring.

[This corrects the article DOI: 10.3389/fcvm.2023.1195509.].

Guidance on left bundle branch pacing using continuous pacing technique and changes in lead V1 characteristics under real-time monitoring.

Background: The changes in the morphology and characteristics of the V1 leads during left bundle branch capturing still need to be fully understood. Objective: This study aims to provide some suggestions about the LBB capture process through the morphology and characteristics of the V1 lead. Method: LBBP using the continuous pacing and morphology monitoring technique during screw-in using a revolving connector (John Jiang's connecting cable). The morphology and features of V1 leads are recorded by continuous monitoring technology. Results: The most common morphology in the LVSP stage is QR, while in the NS-LBBP (low output) stage and the NS-LBBP (lower output) stage, it is rSR. In the S-LBBP stage, it is rsR. The predominant morphology is with r/R waves in S-LBBP, which includes variations like rSR, rsR, rSr, rsr, rR, rs, rS, and R type, making up 96.7% of the total. The r waves in lead V1 are associated with agitated myocardium conducted from the left bundle branch. Conclusion: The initial r-wave in lead V1 may be a marker during the follow-up of patients with selective LBB capture.

Prophylactic Efficacy and Safety of Antithrombotic Regimens in Patients with Stable Atherosclerotic Cardiovascular Disease (S-ASCVD): A Bayesian Network Meta-Regression Analysis.

OBJECTIVE: The aim of this study was to evaluate the efficacy and safety of antithrombotic regimens and their combinations in preventing thrombotic incidents in patients with stable atherosclerotic cardiovascular disease (S-ASCVD). METHODS: A systematic literature search was conducted in the PubMed, Embase, Cochrane Library, Scopus, and Google Scholar databases. The primary comprehensive endpoint was a major adverse cardiovascular event (MACE) composite of cardiovascular death, stroke, or myocardial infarction, while the secondary endpoints were cardiovascular death, all-cause stroke, ischemic stroke, myocardial infarction, and all-cause death. The safety endpoint was major bleeding. Bayesian network meta-regression analysis in R software was used to calculate the final effect size and to correct for the effect of follow-up time on the outcome effect size. RESULTS: Twelve studies reporting 122,190 patients with eight antithrombotic regimens were included in this systematic review. For the primary composite endpoint, low-dose aspirin plus clopidogrel 75 mg (hazard ratio [HR] 0.53, 95% confidence interval [CI] 0.33-0.87) and low-dose aspirin plus rivaroxaban 2.5 mg twice daily (HR 0.53, 95% CI 0.34-0.82) showed significantly better efficacy than clopidogrel monotherapy, and the efficacy was comparable among the first two regimens. Unfortunately, none of the active regimens significantly decreased all-cause death, cardiovascular death branch, and all-cause stroke as part of the secondary endpoints. Low-dose aspirin plus ticagrelor 90 mg twice daily (HR 0.81, 95% CI 0.69-0.94) and low-dose aspirin plus ticagrelor 60 mg twice daily (HR 0.84, 95% CI 0.74-0.95) had a significant advantage in myocardial infarction compared with low-dose aspirin monotherapy, while low-dose aspirin plus 2.5 mg rivaroxaban twice daily (HR 0.62, 95% CI 0.41-0.94) was better than low-dose aspirin in the treatment of ischemic stroke. In the major bleeding branch, low-dose aspirin plus ticagrelor 90 mg twice daily (HR 2.2, 95% CI 1.70-2.90), low-dose aspirin plus ticagrelor 60 mg twice daily (HR 2.1, 95% CI 1.70-2.60), low-dose aspirin plus rivaroxaban 2.5 mg twice daily (HR 1.7, 95% CI 1.30-2.00), and rivaroxaban 5 mg twice daily (HR 1.5, 95% CI 1.20-1.90) showed higher major bleeding risk compared with low-dose aspirin. CONCLUSIONS: Considering MACEs, myocardial infarction, all kinds of stroke, ischemic stroke, and major bleeding, low-dose aspirin plus rivaroxaban 2.5 mg twice daily should be considered the preferred regimen for S-ASCVD patients with low bleeding risk.

The electrophysiological characteristics and meanings in left bundle branch pacing based on unipolar and bipolar pacing.

Left bundle branch pacing (LBBP) is considered as an innovative physiologic pacing form because of lower thresholds compared with His bundle pacing and can partially resolve distal bundle disease (1). Our group had reported a novel LBBP lead implantation procedure guided by electrocardiogram (ECG) and electrogram (EGM) morphology under beat-to-beat monitoring, and found the isoelectric interval was a safe and precise endpoint for implantation, and was feasible in 87.8% (2). Few studies described the ECG and EGM characteristics of bipolar pacing due to the inaccuracy of selective left bundle branch pacing (SLBBP). This is the first case to report the electrophysiological characteristics of four unipolar or bipolar pacing modes and try to analyze the potential mechanism of different ECG and EGM morphology.

2:1 Intrahisian block with Wenckebach phenomenon during his bundle pacing.

BACKGROUND: Intrahisian blocks with split His bundle (HB) potentials are occasionally observed in practice with intrahisian Wenckebach phenomenon being rare. CASE PRESENTATION: We report a case of an 85c and third-degree atrioventricular block. Some electrophysiological phenomena were recorded which serve as evidence of second-degree block intrahisian within the HB. During HB pacing (HBP) lead deployment, widening and splitting of HB potential and intrahisian Wenckebach phenomenon were recorded in intracardiac electrogram. Then, we began unipolar HBP at 2 V/0.5 ms. The paced QRS exhibited morphology identical to that during intrinsic rhythm, indicating selective capture of the HB. Notably, pacing the H1 potential at 750 ms results in 2:1 intrahisian block with intrahisian Wenckebach phenomenon. CONCLUSION: The case highlights the interesting finding of second-degree block intrahisian block in the HBP.

Interesting phenomena during threshold testing of conduction system pacing: What is the mechanism?

BACKGROUND: Although the interest in conduction system pacing is increasing, the data on longitudinal dissociation in the literature is still limited. METHODS AND RESULTS: We performed left bundle branch (LBB) pacing on a patient with sick sinus syndrome and atrioventricular block. The transition of QRS morphology can be observed during the threshold testing. The main findings were different left ventricular activation times when selective LBB capture was performed at different outputs. CONCLUSIONS: This phenomenon may be due to the anatomical basis of longitudinal dissociation of the His-Purkinje system, which allows pacing stimulation at different thresholds to excite different portions of the conduction system.

A Continuous Pacing and Recording Technique for Differentiating Left Bundle Branch Pacing From Left Ventricular Septal Pacing: Electrophysiologic Evidence From an Intrapatient-Controlled Study.

BACKGROUND: Left bundle branch pacing (LBBP) is a promising approach for achieving near-physiologic pacing. However, differentiating LBBP from left ventricular septal endocardial pacing (LVS(e)P) remains a challenge. This study aimed to establish a simple and effective method for differentiating LBBP from LVS(e)P and to evaluate their electrophysiologic characteristics. METHODS: LBBP, using continuous uninterrupted pacing and real-time monitoring of electrocardiograms along with intracardiac electrograms, was performed in 97 consecutive patients. We evaluated the electrophysiologic characteristics observed during LBBP using 6 modalities: right ventricular septal pacing (RVSP), intraventricular septal pacing (IVSP 1 and 2), LVS(e)P, nonselective LBBP (NSLBBP), and selective LBBP (SLBBP). RESULTS: Of the 97 patients, 87 (89.7%) met the criteria (abrupt change in paced QRS morphology with a transition from Qr to QR/qR in lead V1 and shortening of stimulus to V6 R-wave peak time [Stim-V6RWPT] of ≥ 10 ms with constant output while rather than after lead screwing) for nonselective left bundle branch (LBB) capture. Selective LBB capture was observed in 82 patients (84.5%). The Stim-V6RWPT of NSLBBP and SLBBP were significantly shorter than LVS(e)P (respectively, 67.1 ± 8.7 ms, 67.0 ± 9.3 ms, and 82.1 ± 10.9 ms). Stim-QRSend was the narrowest in IVSP2 (136.6 ± 15.2 ms) instead of NSLBBP (140.0 ± 17.1 ms). CONCLUSIONS: The uninterrupted pacing technique for differentiating LBBP from LVS(e)P in the same group of patients is feasible. Electrophysiologic evidence from our intrapatient-controlled study shows that LBBP and LVS(e)P differ in ventricular electrical synchronization.

Premature beat of selective left bundle branch: a novel marker for reaching and capturing the left bundle branch.

BACKGROUND: It was recently shown that template beats and fixation beats of the premature ventricular contractions (PVCs) were generated during lead deployment. These could be exploited to guide the left bundle branch (LBB) pacing (LBBP) procedure. However, lack of a revolving connector that can continuously record and pace during lead rotations has been a limitation when using the traditional implant technique. Here, we report ten cases in which a revolving connector was used and showed that the premature beats of selective left bundle branch (SLBB-PBs) were generated as the lead was reached and the electrical stimulus selectively captured the LBB. METHODS AND RESULTS: Ten patients who underwent the transseptal placement of the pacing lead using a revolving connector were included in the study. We aimed to examine whether the SLBB-PB was a marker of LBB capture during LBBP and the clinical significance of SLBB-PB. LBBP was performed and data of these cases were analyzed to show the characteristics of the electrocardiogram and the intracardiac electrogram of SLBB-PBs. CONCLUSIONS: This is the first case series on SLBB-PBs in LBBP. The presence of SLBB-PBs suggested that the LBB was reached and selectively captured and possibly increased the safety of lead implantation.

Right subclavian vein approach for selective left bundle branch pacing: A case report.

We reported a 65-year-old man with symptomatic bradycardia caused by chronic atrial fibrillation who underwent pacemaker implantation by left bundle branch pacing (LBBP) via right subclavian vein (RSV) approach. A tricuspid valve annulus (TVA) angiography was performed, and a different connecting cable that can monitor electrocardiograms (ECG) and intracardiac electrograms (EGM) in real time was used during the process. By TVA angiography, we could easily find the ideal location of LBBP; a new connecting cable helped us avoid perforation and guide effective endpoint without the need to stop pacing. The case showed that it was feasible and safe to use the new method for LBBP through RSV route.

Case report: Left bundle branch pacing guided by real-time monitoring of current of injury and electrocardiography.

Background: Left bundle branch (LBB) pacing (LBBP) has recently emerged as a physiological pacing mode. Current of injury (COI) can be used as the basis for electrode fixation position and detection of perforation. However, because the intermittent pacing method cannot monitor the changes in COI in real time, it cannot obtain information about the entire COI change process during implantation. Case summary: Left bundle branch pacing was achieved for treatment of atrioventricular block in a 76-year-old female. Uninterrupted electrocardiogram and electrogram were recorded on an electrophysiology system. In contrast to the interrupted pacing method, this continuous pacing and recording technique enables real-time monitoring of the change in ventricular COI and the paced QRS complex as the lead advances into the interventricular septum. During the entire screw-in process, the COI amplitude increased and then decreased gradually after reaching the peak, followed by a small but significant, rather than dramatic, decrease. Conclusion: This case report aims to demonstrate the clinical significance of changes in COI and QRS morphology for LBBP using real-time electrocardiographic monitoring and filtered and unfiltered electrograms when the lead is deployed using a continuous pacing technique. The technique could be used to confirm LBB capture and avoid perforation.

The left bundle branch has been captured but shows the left ventricular septal pacing:What is the mechanism?

It was shown that V6 R-wave peak time (V6 RWPT) prolongs with transition form non-selective left bundle branch pacing (ns-LBBP) to left ventricular septal pacing (LVSP) but remains constant or slightly prolongs with transition to selective left bundle branch pacing (sel-LBBP) [1,2]. Here, we report on a patient who was observed with a LBB potential, isoelectric interval, where the V6 RWPT substantially prolonged with transition from ns-LBBP to sel-LBBP at near threshold output.

Evaluation of the shortening of the stimulus-to-peak left ventricular activation time at continuous low output to confirm left bundle branch capture.

Background: Left bundle branch area pacing (LBBAP) is a physiological pacing method for treatment of atrioventricular block. However, there is a need for a new convenient and safe method for performing left bundle branch pacing (LBBP) and to confirm left conduction system capture. Objective: This study aimed to explore a new convenient and safe method for performing selective LBBP. Methods: A total of 28 patients who had indications for pacing therapy and received LBBAP were recruited retrospectively. Demographic and baseline patient characteristics, electrocardiograms, pacing parameters, and intracardiac electrogram pattern were evaluated. Continuous unipolar pacing at low output (2 V / 0.5 ms) was performed during the whole period of LBBP lead implantation. Successful left bundle branch (LBB) capture was defined as the abrupt change of the pacing stimulus to the peak of R wave in lead V5 during continuous pacing at low output (2 V / 0.5 ms). Results: The parameters of the 2 shortenings (stimulus-to-peak left ventricular activation time [S-peak LVAT] before shortening, S-peak LVAT after shortening, and the duration of shortening) all showed a significant positive correlation (Pearson product-moment correlation coefficient [PCC] = 0.915, P < .001; PCC = 0.897, P < 0.001; PCCs = 0.765, P < 0.001). Shortening of the S-peak LVAT with continuous low output had a 100% sensitivity and 33.3% specificity for predicting stimulus-ventricular potential interval (S-V interval). Conclusion: Abrupt shortening of the S-peak LVAT at continuous low output was associated with abrupt shortening of the S-peak LVAT at low and high output. High rate of selective LBB capture can be achieved with the method of continuous low output, shortening the S-peak LVAT.