Review of Atrioventricular Node Ablation Combined with Permanent His-Purkinje Conduction System Pacing in Patients with Atrial Fibrillation with Heart Failure.

With the advancement of pacing technologies, His-Purkinje conduction system pacing (HPCSP) has been increasingly recognized as superior to conventional right ventricular pacing (RVP) and biventricular pacing (BVP). This method is characterized by a series of strategies that either strengthen the native cardiac conduction system or fully preserve physical atrioventricular activation, ensuring optimal clinical outcomes. Treatment with HPCSP is divided into two pacing categories, His bundle pacing (HBP) and left bundle branch pacing (LBBP), and when combined with atrioventricular node ablation (AVNA), can significantly improve left ventricular (LV) function. It effectively prevents tachycardia and regulates ventricular rates, demonstrating its efficacy and safety across different QRS wave complex durations. Therefore, HPCSP combined with AVNA can alleviate symptoms and improve the quality of life in patients with persistent atrial fibrillation (AF) who are unresponsive to multiple radiofrequency ablation, particularly those with concomitant heart failure (HF) who are at risk of further deterioration. As a result, this "pace and ablate" strategy could become a first-line treatment for refractory AF. As a pacing modality, HBP faces challenges in achieving precise localization and tends to increase the pacing threshold. Thus, LBBP has emerged as a novel approach within HPCSP, offering lower thresholds, higher sensing amplitudes, and improved success rates, potentially making it a preferable alternative to HBP. Future large-scale, prospective, and randomized controlled studies are needed to evaluate patient selection and implantation technology, aiming to clarify the differential clinical outcomes between pacing modalities.

Right ventriculography to guide left bundle branch pacing in pacing-induced cardiomyopathy: a novel case report.

Background: There is emerging evidence for the potential utility of left bundle branch area pacing (LBBAP), as an alternative to conventional cardiac resynchronization therapy (CRT). The utility of right ventriculography by way of power injector to facilitate lead placement has not yet been reported in the literature. Case summary: A 79-year-old female, with a background of poorly rate-controlled atrial fibrillation, presented with worsening dyspnoea. She had recently undergone single-chamber pacemaker insertion prior to an atrioventricular nodal (AVN) ablation, owing to failure in achieving successful CRT coronary sinus lead placement. She had clinical evidence of volume overload, and her electrocardiogram demonstrated right ventricular pacing. Echocardiography demonstrated left ventricular (LV) impairment, with an ejection fraction (EF) of 35%, and severe functional mitral regurgitation (MR). Her diagnosis was overall consistent with pacing-induced cardiomyopathy (PIC). In this patient, the use of right ventriculography, using power-injector-delivered contrast, successfully facilitated placement of an LBBAP lead, with confirmation of good threshold and sensing parameters. Following an upgrade to conduction system pacing, the patient recovered well. On recent follow-up, repeat echocardiography (24 months post initial presentation) demonstrated improved LV function (EF 45% from 35%) and only mild-to-moderate MR. Discussion: In conclusion, we demonstrate the utility of right ventriculography to facilitate placement of an LBBAP lead, successfully treating a patient who developed PIC from chronic right ventricular pacing following AVN ablation.

Case Report: Differences in self-selected pacing in 20, 40, and 60 ironman-distance triathlons: a case study.

Background: Triathletes are pushing their limits in multi-stage Ironman-distance triathlons. In the present case study, we investigated the pacing during 20, 40, and 60 Ironman-distance triathlons in 20, 40, and 60 days, respectively, of one professional IRONMAN® triathlete. Case study: Event 1 (20 Ironman-distance triathlons in 20 days), Event 2 (40 Ironman-distance triathlons in 40 days), and Event 3 (60 Ironman-distance triathlons in 60 days) were analyzed by discipline (swimming, cycling, running, and overall event time), by Deca intervals (10 days of consecutive Ironman-distance triathlons) and additional data (sleep duration, body mass, heart rate in cycling and running). To test differences between Events and Deca intervals within the same discipline, T-tests (2 groups) or one-way ANOVAs (3 or more groups) were used. Results: Swimming splits were fastest in Event 1, (ii) cycling and running splits were fastest in both Event 2 and 3, (iii) overall speed was fastest in Event 3, (iv) sleep duration increased during Event 2 but decreased in Event 3, (v) body mass decreased in Event 2, but increased in Event 3 and (vi) heart rate during cycling was similar in both Event 2 and 3. In contrast, heart rate during running was greater in Event 3. Conclusion: In a professional IRONMAN® triathlete finishing 20, 40, and 60 Ironman-distance triathlons in 20, 40, and 60 days, respectively, split performances and both anthropometrical and physiological changes such as body mass and heart rate differed depending upon the duration of the events.

Left bundle branch area pacing: A new era of cardiac resynchronization therapy?

The recent systematic review and meta-analysis provided a comprehensive focus on the current state of cardiac resynchronization therapy (CRT). The authors determined the feasibility of physiological left bundle branch area pacing (LBBAP) in patients indicated for CRT through a careful analysis of trials. They found that LBBAP was associated with significant reductions in QRS duration, New York Heart Association functional class, B-type natriuretic peptide levels, and pacing thresholds as well as improvements in echocardiographic parameters compared to biventricular pacing.

Left-bundle branch optimized CRT implantation in a patient with persistent left superior vena cava.

Persistent left superior vena cava (PLSVC) is one of the anatomical variations, which can make device implantation more challenging and lead to incorrect lead placement, dislodgement, and procedure failure. Conduction system pacing (CSP) can be an alternative to traditional CRT implantation. Herein, we describe a brief case report of successful LBBAP-optimized CRT (LOT-CRT) via an innominate vein in a patient with PLSVC.

His bundle pacing combined with atrioventricular node ablation for atrial fibrillation: a systematic review and meta-analysis.

INTRODUCTION AND OBJECTIVE: His bundle pacing (HBP) could replace failed biventricular pacing (BVP) in guidelines (IIa Indication), but the high capture thresholds and backup lead pacing requirements limit its development. We assessed the efficacy and safety of HBP combined with atrioventricular node ablation (AVNA) for atrial fibrillation (AF) and compared with BVP and left bundle branch pacing (LBBP). METHODS: We reviewed PubMed, Embase, Web of Science, and Cochrane Library databases on left ventricular ejection fraction (LVEF), New York Heart Association (NYHA) score, QRS duration (QRSd), and pacing threshold. RESULTS: Thirteen studies included 1115 patients (639 with HBP, 338 with BVP, and 221 with LBBP). Compared with baseline, HBP improved LVEF (mean difference [MD]: 9.24 [6.10, 12.37]; p < 0.01), reduced NYHA score (MD: -1.12 [-1.34, -0.91]; p < 0.01), increased QRSd (MD: 10.08 [4.45, 15.70]; p < 0.01), and rose pacing threshold (MD: 0.16 [0.05, 0.26]; p < 0.01). HBP had comparable efficacy to BVP and LBBP and lower QRSd (p < 0.05). HBP had a lower success rate (85.97%) and more complications (16.1%). CONCLUSION: HBP combined with AVNA is effective for AF, despite having a lower success rate and more complications. Further trials are required to determine whether HBP is superior to BVP and LBBP.

Reply to the comments on "Effect of Bedside Ultrasound­Guided Versus Fluoroscopy­Guided Transvenous Cardiac Temporary Pacing in Children with Bradyarrhythmia".

The article "Effect of Bedside Ultrasound­Guided Versus Fluoroscopy­Guided Transvenous Cardiac Temporary Pacing in Children with Bradyarrhythmia" offers valuable insights into comparative short-term pacing strategies for pediatric bradyarrhythmias. There are some comments that the study overlooks the impact of genetic factors on bradyarrhythmias and treatment outcomes, lacks detailed information on the influence of medications, and does not address the cost-effectiveness of the pacing techniques. The analysis and explanation are made here, and it is hoped that through further research in the future, the conclusions will be more reliable.

Optimizing electrical efficacy of leadless cardiac resynchronization therapy and leadless left ventricular septal pacing: Insights on left and right ventricular activation from electrocardiographic imaging.

Background: Leadless cardiac resynchronization therapy (CRT) is an emerging heart failure treatment. An implanted electrode delivers lateral or septal endocardial left ventricular (LV) pacing (LVP) upon detection of a right ventricular (RV) pacing stimulus from a coimplanted device, thus generating biventricular pacing (BiVP). Electrical efficacy data regarding this therapy, particularly leadless LV septal pacing (LVSP) for potential conduction system capture, are limited. Objectives: The purpose of this study was to evaluate the acute performance of leadless CRT using electrocardiographic imaging (ECGi) and assess the optimal pacing modality (OPM) of LVSP on the basis of RV and LV activation. Methods: Ten WiSE-CRT recipients underwent an ECGi study testing: RV pacing, BiVP, LVP only, and LVP with an optimized atrioventricular delay (LV-OPT). BiV, LV, and RV activation times (shortest time taken to activate 90% of the ventricles [BIVAT-90], shortest time taken to activate 95% of the LV, and shortest time taken to activate 90% of the RV) plus LV and BiV dyssynchrony index (standard deviation of LV activation times and standard deviation of all activation times) were calculated from reconstructed epicardial electrograms. The individual OPM yielding the greatest improvement from baseline was determined. Results: BiVP generated a 23.7% improvement in BiVAT-90 (P = .002). An improvement of 43.3% was observed at the OPM (P = .0001), primarily through reductions in shortest time taken to activate 90% of the RV. At the OPM, BiVAT-90 improved in patients with lateral (43.3%; P = .0001; n = 5) and septal (42.4%; P = .009; n = 5) LV implants. The OPM varied by individual. LVP and LV-OPT were mostly superior in patients with LVSP, and in those with sinus rhythm and left bundle branch block (n = 4). Conclusion: Leadless CRT significantly improves acute ECGi-derived activation and dyssynchrony metrics. Using an individualized OPM improves efficacy in selected patients. Effective LVSP is feasible, with fusion pacing at LV-OPT mitigating the potential deleterious effects on RV activation.

His-bundle pacing from the right atrium: Solving pacemaker implantation challenges post-TriClip.

INTRODUCTION: This case report highlights the novel role of His-bundle pacing (HBP) from right atrium, not just for preserving cardiac function, but also for avoiding interference with TriClip devices. METHODS AND RESULTS: A 78-year-old female with severe tricuspid regurgitation received two TriClip devices. Postprocedure, frequent significant sinus pauses required a pacemaker. HBP was chosen to avoid lead complications. Under local anesthesia, a His pacing lead was inserted via the axillary vein using specialized catheter. Follow-ups over 2.5 years showed stable parameters with no complications. CONCLUSION: HBP is effective for patients with TriClip devices, ensuring optimal cardiac function and lead stability.

Case Report: Extraction of a stylet-driven lead for left bundle branch area pacing >2†years after implantation.

Left bundle branch pacing has recently emerged as a significant alternative to right ventricular pacing. The rate of implanted stylet-driven septal leads is expected to increase substantially in the coming years, along with the need to manage long-term complications. Experience in extracting these leads is currently very limited; however, the number of complex extractions is anticipated to increase in the future. We report a complex case involving the extraction of a long-dwelling Solia lead used for left bundle branch pacing in a 21-year-old man. The lead was extracted through the implant vein 27 months after implantation, using a methodology that involved a locking stylet and compression coil. The new lead insertion was challenging due to venous occlusion but after successful venoplasty, the His lead was successfully implanted. The postoperative course was uneventful, demonstrating the feasibility of extraction without complications.

Comparison of acute hemodynamic effect of prioritizing ventricular resynchronization versus left ventricular filling during optimization of cardiac resynchronization therapy.

BACKGROUND: Targeting the maximal ventricular resynchronization, with the shortest QRS duration (QRSd), is commonly implemented after cardiac resynchronization therapy (CRT). OBJECTIVE: We compared optimization of ventricular resynchronization with optimization of left ventricular (LV) filling during CRT by measuring their acute hemodynamic effects. METHODS: Patients with standard CRT indications, recruited from two centers, underwent biventricular pacing (BVP) and left bundle branch pacing (LBBP). We performed a within-patient comparison of acute hemodynamic response of systolic blood pressure (SBP) at the atrioventricular delay (AVD) with the shortest QRSd against the AVD with the most efficient LV filling. In a validation sub-study, we also performed electrical assessment using QRS area (QRSa) and hemodynamic assessment with the maximum rate of LV pressure rise (dP/dtmax). RESULTS: Thirty patients (age 65 ± 10, 53% male) were recruited. The AVD producing maximal ventricular resynchronization was associated with a significantly shorter QRSd (difference 15 ± 12 ms for BVP and 18 ± 13 ms for LBBP, both P < 0.01) and a significantly smaller improvement in SBP (difference 3 ± 4 mmHg for BVP, and 2 ± 2 mmHg for LBBP, both P < 0.01) compared with the AVD that optimized filling. Similar findings were observed in the sub-study, with a significantly smaller improvement in dP/dtmax assessed with QRSd and QRSa (difference 9 ± 7% and 6 ± 4% during BVP, and 5 ± 6% and 3 ± 3% during LBBP, all P < 0.01). CONCLUSION: Targeting the maximal ventricular resynchronization results in suboptimal acute hemodynamic performance with both BVP and LBBP as CRT. These findings support prioritizing LV filling when programming AVD for CRT.

A case report of a combined implantation technique of a cardioverter-defibrillator in an infant with long QT syndrome type 8 (Timothy's syndrome).

We present a case of successful implantation of a cardioverter-defibrillator (ICD) using combined technique in a child with Timothy's syndrome. Due to high risk of sudden cardiac death (SCD) such patients often need ICD for primary or secondary prevention but implantation technique in young children remains controversial. The subcutaneous cardioverter-defibrillators could be an option in some cases, however, reliable cardiac pacing should be implemented for patients with bradyarrhythmias. An ICD implantation technique with the epicardial pacing lead placement and subcutaneous tunnel formation for endocardial defibrillation lead seems to be promising in SCD prevention also providing the opportunity for permanent pacing.

Assessment of ventricular electrical heterogeneity in left bundle branch pacing and left ventricular septal pacing by using various electrophysiological methods.

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.

Utility of Cardiac Magnetic Resonance in Assessing Arrhythmic Risk in Patients With Nonischemic Cardiomyopathy Undergoing Biventricular Pacing.

BACKGROUND: Nonischemic cardiomyopathy (NICM) is responsible for approximately one-third of heart failure and is associated with significant morbidity and mortality. Recent data suggested the lack of mortality reduction from adding a defibrillator to cardiac resynchronization therapy (CRT) in all patients with NICM. Myocardial fibrosis detected by cardiac magnetic resonance late gadolinium enhancement (CMR-LGE) can help risk stratify patients who would benefit from adding a defibrillator to CRT in this patient population. OBJECTIVES: We aim to assess the relationship between the presence of myocardial fibrosis detected by CMR-LGE and the rate of major arrhythmic events (MAE) that included sustained ventricular tachycardia (VT), appropriate cardiac resynchronization therapy-defibrillator (CRT-D) intervention, ventricular fibrillation (VF), and sudden cardiac death (SCD) in patients with NICM undergoing CRT and to compare all-cause mortality and heart failure improvement between patients receiving cardiac resynchronization therapy-pacing (CRT-P) versus those receiving CRT-D based on the presence of myocardial fibrosis. METHODS: All consecutive patients with NICM satisfying a guideline-directed indication for CRT implantation were included in the study after excluding patients who refused to consent, patients with acute decompensated heart failure, and those contraindicated for a cardiac magnetic resonance (CMR). Patients were divided into two groups based on the presence of fibrosis in cardiac MRI: the LGE/CRT-D group and the No LGE/CRT-P group. They were then followed for 1 year. RESULTS: Sixty patients were enrolled. Sixteen patients (26.6%) developed MAE during the study duration, among those patients, seven had myocardial fibrosis (receiving CRT-D as per protocol), while nine had no myocardial fibrosis (receiving CRT-P as per protocol), (41.2% vs. 20.9%, p = 0.045). The presence of CMR-LGE, regardless of the extent and distribution, predicted MAE with an odds ratio of 2.6 (CI = 1.78-8.9, p = 0.04). The presence of ≥7.5% of myocardial fibrosis by CMR was associated with 54% sensitivity and 100% specificity for MAE in the study population. All-cause mortality was significantly higher in the No LGE/CRT-P group versus the LGE/CRT-D group (15 [34.9%] vs. 2 [11.8%], p = 0.076). CONCLUSION: In patients with NICM candidates for biventricular pacing, the presence of LGE on CMR, irrespective of the extent or segmental pattern, is independently associated with an MAE and is associated with worse heart failure outcomes. However, the absence of LGE did not rule out MAE, and implanting CRT-P based on lack of fibrosis may result in higher all-cause mortality.

Pacing Cycle Length-Dependent Electrophysiological Changes in Left Atrium: Poor Validity of Using Low Voltage Area and Slow Conduction Area under Specific Pacing Cycle Length as Absolute Substrates of Atrial Fibrillation.

BACKGROUND: Pacing cycle length (PCL)-dependent changes in left atrial (LA) electrophysiological properties have not been fully elucidated. OBJECTIVE: To elucidate these changes using a high-resolution mapping system. METHODS: Forty-eight patients underwent atrial fibrillation ablation with RHYTHMIA HDx™. Paired LA maps under a baseline PCL (600 ms) and rapid PCL (300 ms) were acquired after pulmonary vein isolation under right atrial appendage pacing. The PCL-dependent change in the low-voltage area (LVA) (area with <0.5 mV bipolar voltage), LA activation time (interval from first LA activation to wavefront collision at lateral wall), regional mean voltage, regional mean wave propagation velocity, and slow conduction area (area with <0.3-m/s wave propagation velocity) were quantitatively analyzed. RESULTS: Under the rapid PCL, the total LVA was significantly increased (7.6 ± 9.5 vs. 6.7 ± 7.6 cm2, p = 0.031), especially in patients with a ≥10 cm2 LVA on the baseline PCL map (21.5 ± 9.1 vs. 18.1 ± 6.5 cm2, p = 0.013). The LA activation time was also prolonged (87.9 ± 16.2 vs. 84.0 ± 14.0 ms, p < 0.0001). Although the rapid PCL did not decrease the regional mean voltage, it significantly decreased the regional mean wave propagation velocity and increased the slow conduction area in all measured regions. CONCLUSION: LVA and slow conduction area can be emphasized by rapid PCL LA mapping. There may be poor validity in using these areas as absolute atrial fibrillation substrates without considering the PCL-dependent changes.

Permanent left bundle branch area pacing improves mitral regurgitation and cardiac function in patients with right bundle branch block.

BACKGROUND: Permanent left bundle branch area pacing (LBBAP) has been established as an effective means to correct left bundle branch block. Right bundle branch block (RBBB), emerge as a distinct form of cardiac conduction abnormality, can be seen in the context of LBBAP procedure. However, the correction potential of LBBAP in patients with RBBB remains largely unexplored. OBJECTIVE: The objective of this study was to evaluate the efficacy and safety of permanent LBBAP in patients with RBBB. METHODS: Ninety-two consecutive patients who underwent successful permanent LBBAP were recruited from May. 2019 to Dec. 2022 in Fuwai Central China Cardiovascular Hospital. Among them, 20 patients with RBBB were included in our analysis. These patients were followed up at 1, 3, 6 and 12 months post-LBBAP. The QRS duration (QRSd) on the V1 lead of the 12-lead elctrocardiogram was measured and compared before and after the LBBAP procedure. Additionally, mitral regurgitation, tricuspid regurgitation and cardiac function were assessed using transthoracic echocardiography, specifically focusing on left ventricular ejection fraction (LVEF) and mitral regurgitation severity. The acute pitfills and delayed complications associated with the LBBAP procedure were recorded to evaluate its safety. SPSS 23.0 was used to perform statistical analysis with Student's t test or one way ANOVA or nonparametric tests (paired Wilcoxon test). A p value less than 0.05 was defined as significant. RESULTS: The demographic breakdown of the RBBB cohort revealed a mean age of 66.35 ± 11.55 years, 60% being male. Comorbidities were prevalent, including severe atrioventricular block (AVB) in 75%, sick sinus syndrome (SSS) in 20%, heart failure in 25%, atrial fibrillation in 30%, coronary heart diseases in 45%, hypertension in 35%, and diabetes mellitus in 15%. Regarding the LBBAP procedure, the average operation time was 106.53 ± 2.72 min, with 45% of patients (9 individuals) requiring temporary cardiac pacing during the surgery. Notably, the LBBAP procedure significantly narrow the QRS duration in RBBB patients, from 132.60 ± 31.49ms to 119.55 ± 18.58 ms (P = 0.046). Additionally, at the 12-month follow-up, we observed a marked improvement in LVEF, which increased significantly from 55.15 ± 10.84% to 58.5 ± 10.55% (P = 0.018). Furthermore, mitral regurgitation severity improved, with a median reduction from 4.46 (0.9, 7.3) to 2.29 (0, 3.49) cm2 (P = 0.033). Importantly, no cases of ventricular septum perforation or pericardial effusion were reported during the LBBAP procedure or during the follow-up period. CONCLUSION: LBBAP provides an immediate reduction in QRS duration for patients suffering from RBBB, accompanied by improvements in mitral regurgitation and cardiac function as evident in the 12-month follow-up period.

Conduction system pacing associated with reduced heart failure hospitalizations and all-cause mortality compared with traditional right ventricular pacing in the Medicare population.

BACKGROUND: Conduction system pacing (CSP) has emerged as an alternative therapy to traditional right ventricular (RV) pacing. However, most CSP studies reflect small cohorts or single-center experience. OBJECTIVE: This analysis compared CSP with dual-chamber (DC) RV pacing in a large, population-based cohort using data from the Micra Coverage with Evidence Development study. METHODS: Medicare administrative claims data were used to identify patients implanted with a DC RV pacemaker. Lead placement data from Medtronic's device registration system identified patients treated with CSP (n = 6197) using a 3830 catheter-delivered lead or DC RV (non-3830 lead, non-CSP placement; n = 16,989) at the same centers. CSP patients were stratified into left bundle branch area pacing (LBBAP; n = 4738) and His bundle pacing (HBP; n = 1459). Incident heart failure hospitalizations, all-cause mortality, complication rates, and reinterventions at 6 months were analyzed. RESULTS: CSP patients with a 3830 catheter-delivered lead experienced significantly lower rates of incident heart failure hospitalization (hazard ratio [HR], 0.70; P = .02) and all-cause mortality at 6 months compared with DC RV patients (HR, 0.66; P < .0001). There was no difference in chronic complications (HR, 0.97; P = .62) or need for reintervention (HR, 0.95; P = .63) with CSP compared with DC RV, although LBBAP patients experienced significantly lower rates of complications (HR, 0.71; P = .001) compared with HBP. CONCLUSION: DC pacemaker patients treated with CSP using a 3830 catheter-delivered lead experienced significant all-cause mortality and heart failure hospitalization benefits compared with DC RV pacing. LBBAP had lower complications compared with HBP. These real-world results align with findings in small clinical studies demonstrating the benefits of CSP.