Bundle Pacing Research Articles

Larger QRS but better hemodynamic function after high output His bundle pacing in patients with heart failure and narrow QRS. A paradox or a new concept?

Abstract Background QRS duration is an important factor in determining Cardiac Resynchronisation Therapy (CRT) response and a useful surrogate for electromechanical dyssynchrony. However, we don’t have studies confirming this concept in conduction system pacing. Purpose We performed His Bundle Pacing (HBP) with high output (3.5V/1msec) in HF patients with dilated or ischemic cardiomyopathy and narrow QRS to evaluate hemodynamic benefit independent of the QRS duration or AV delay shortening. Methods 14 patients with dilated (7 patients) or ischemic (7 patients) cardiomyopathy (EF<35%) and narrow QRS (<120ms) were referred for implantation of a defibrillator. We implanted an ICD- HBP system, and we collected clinical, echocardiographic, and electrocardiographic data. Results We obtained HBP in all 14 patients successfully. PQ after implantation was shorter from 172±48 to 143±16 (P=0.048) so as to pace the ventricle. Baseline QRS duration increased after pacing from 110±15 to 123±16ms (P=0.008) as measured by ECG analyzer. Despite this increase in QRS duration basal mean EF increased from 30±4% to 46±10% (P<0.001) after a median follow-up of 17 months. Left ventricular end-diastolic diameter and left ventricular end-diastolic volume decreased from 62±5 to 57±5mm (P=0.013) and from 195±69 to 126±27ml (P<0.001), respectively. Left ventricular end-systolic volume decreased from 139±58 to 69±27 (P<0.001). TAPSE increased from 19±4 to 27±4. NYHA class decreased by one class in every patient after only one month. HBP threshold was 1.05V±0.7/1msec and raised to 1.33±0.93/1msec (due mainly to 2 patients with very high threshold). The impedance was 588±109 and decreased to 484±69 Ohms. R-wave at implant was 3.2±1.8mV. In 2 out of 14 patients, threshold increased but was still less than 3.5V/1msec. Conclusions HBP in HF patients with dilated or ischemic cardiomyopathy and narrow QRS improves hemodynamic function in right and left ventricle and decreases NYHA class. This benefit appears to be produced by a higher stimulation output despite a larger QRS after pacing. We exclude that a very short AV delay could be favorable, by measuring acute EF changes only after increasing the pacing output without AV delay modifications. To our knowledge these are the first cases of beneficial HBP in HF patients with narrow QRS. Interestingly, larger QRS corresponds to higher EF in patients with high output HIs Bundle Pacing.

Verification of intra- and inter-atrial conduction during Bachmann's bundle pacing using longitudinal bi-atrial strain

Abstract Introduction Although atrial septal pacing has been reported to reduce atrial fibrillation (AF) burden, there is less evidence regarding its effect on the prevention of permanent AF and the improvement of long-term clinical outcomes. However, Bachmann's bundle pacing (BBp), which features P-wave morphology similar to sinus rhythm and shortened P-wave duration (PWD), was reported to significantly reduce permanent AF recurrences and occurrences compared with right atrial appendage pacing (RAAp) and non-specific right septal pacing. Purpose Possible mechanisms for AF suppression with BBp are that fast inter-atrial conduction through BB decreases global atrial activation time and the dispersion of the overall atrial refractoriness, and it prevents the decrease in left ventricular filling and increase in left atrial pressure associated with delayed left atrial contraction. Intra-and inter-atrial conduction during BBp was evaluated using longitudinal bi-atrial strain. Methods In patients with successful BBp implantation defined by electrocardiographic criteria using SelectSecure pacing lead and C315 delivery catheter (Medtronic, Inc), both left atrium (LA) and right atrium (RA) global longitudinal strain (GLS) in simultaneous phases were measured using Philips Ultrasound Workspace 2D Strain in apical 4-chamber view during atrial pacing to assess intra- and inter-atrial conduction delay. The atrial GLS were measured semi-automatically, and the strain rate was analyzed in the three segments of septal wall, lateral wall, and roof and their average. The negative peak of strain rate during atrial systole was the starting point of atrial contraction, and time to peak (TTP) was measured. The difference in TTP between septal and lateral walls in each atrium was measured as intra-atrial conduction delay and the difference in average TTP between LA and RA as inter-atrial conduction delay. Results Ten patients who underwent successful BBp were enrolled (Sick sinus syndrome: 3, advanced atrioventricular block: 2, complete atrioventricular block: 5). At implantation, bipolar atrial electrogram amplitude was 2.03±0.93 mV, atrial lead impedance was 632.7±157.6 Ω, and atrial pacing threshold was 0.7±0.2 V at 0.4 ms. The PWD during sinus rhythm on the 12-lead ECG was 132.8±10.6 ms, while during BBp it was 108.0±11.9 ms, which was significantly shorter in the BBp group (p<0.001). The intra-atrial conduction delay in RA and LA was 10.9 ± 12.1 ms and 12.1 ± 17.3 ms, respectively, and the inter-atrial conduction delay was 6.6 ± 8.6 ms. On the other hand, for the 10 RAAp and 10 sinus rhythm patients as control groups, the inter-atrial conduction delay was 29.7±13.8 ms and 8.5±9.5 ms, respectively. BBp had significantly less inter-atrial conduction delay than RAAp (p=0.005) and was comparable to sinus rhythm (p=0.719). Conclusion Longitudinal bi-atrial strain suggested that BBp significantly reduced inter-atrial delay and it might be effective in AF suppression.Longitudinal bi-atrial strain

Conduction system pacing and atrioventricular node ablation for atrial fibrillation - a systematic review and meta-analysis

Abstract Background/Introduction Biventricular pacing (BVP) has been shown to reduce the risk of heart failure following atrioventricular node ablation (AVNA) for the management of medically refractory atrial fibrillation (AF) when compared with conventional right ventricular pacing.[1] Conduction system pacing (CSP) is an emerging cardiac synchronization alternative to BVP[2], however, its evidence in AVNA for AF is limited. Purpose To evaluate the effect of CSP on left ventricular ejection fraction (LVEF), QRS duration (QRSd), pacing threshold and New York Heart Association (NYHA) class score following AVNA for AF. Methods We conducted a literature review of PUBMED, MEDLINE, EMBASE, Cochrane Library, and Web of Science for randomized clinical trials (RCTs) and observational studies evaluating CSP (His bundle pacing and left bundle branch pacing) post AVNA for AF. Out of 14 studies comprising 1112 patients, we conducted meta-analyses evaluating the impact of CSP on LVEF and QRS. Ten studies were pooled to assess outcomes pre- and post-implantation of CSP following AVNA. Three observational studies and one RCT were included in the meta-analysis comparing outcomes in CSP versus BVP post AVNA. Results CSP resulted in a significant QRSd reduction (-11.01 ms, 95% CI 5.07 - 16.95, p <0.01), improved LVEF (+10.28%, 95% CI 7.03 - 13.52; p <0.01) and improved NYHA score (-1.09; 95% CI -1.41 - -0.78; p <0.01) during follow-up of 6-36 months (Figure 1) from baseline (peri-implantation). There was no significant pacing threshold rise (0.11V; 95% CI -0.14 - 0.36; p= 0.39) observed during the same period. CSP was associated with statistically significant shorter QRSd (-49.81ms; 95% CI, -70.57 - -29.06; p <0.01) when compared to BVP. For LVEF, there was a statistically significant improvement of +8.96% (95% CI 2.55 - 15.37%; p <0.01) with CSP versus BVP. Limited data prohibited comparison of threshold and NYHA outcomes between CSP and BVP. Conclusion Conduction system pacing appears effective in improving baseline LVEF, QRSd and NYHA score in AVNA for AF, and may be a viable alternative to further optimising LVEF and QRSd in comparison to BVP. Further studies are required to evaluate the long-term impact and clinical outcomes of CSP in post AVNA patients.

Extraction of old His bundle pacing leads and coronary sinus leads - an analysis of 3897 lead extraction procedures including 27 His and 253 coronary sinus lead removals

Abstract Background The lumen-less the Medtronic 3830 lead is most popular for His bundle pacing (HBP) and experience with such lead extraction are very limited especially for leads older than 4 years. Methods Analysis of 3898 transvenous lead extraction (TLE) procedures (including 27 HBP and 253 LVP lead extraction) was performed. Results The HBP was used usually in the CRT-D system (72.4%) and EF and NYHA class were better than patients with LVP extracted leads. Age of extracted HBP or LVP lead did not differ significantly (54.5 vs 50.2 months). Extraction of "old" HBP leads extraction was longer than in case of "young HBP leads (8,6 and 3.8 min). Mechanical dilatation was necessary in 63 and 100% extracted HBP leads. Unexpected procedure difficulties appeared (14,3%) and utility of second line / advanced tools had been utilised (28,6%) only when "old" HBP lead were extracted. Difficulties in extracting HBP leads were comparable to those encountered in the extraction of LVP leads of similar age. There was no extracted 3830 extracted lead break and no major complication, necessity of rescue cardiac surgery and procedure related death when HBP and LVP leads were extracted. The length of the FU period for those still alive patients was shorter for patients with removed leads for HBP as this technique was introduced significantly later than LVP. However, the 1-month mortality rate of patients with LVP lead removed is higher than in the HBP and control groups. Conclusions 1. HBP most frequently is utilised in the CRT-D system for resynchronisation of failing heart (72.4%) 2. Extraction of HBP leads is performed most frequently due to non-infective indications (59,3%) and most often because of lead dysfunction (33,3%). 3. Extraction of "old" (>40 mth) HBP leads is twice longer than younger ones (3.8 and 8,6 min) and mechanical dilatation is necessary frequently. 4. Extraction of "old" (>40 mth) HBP leads is more difficult than younger ones due to appearance unexpected procedure difficulties (14,3%) and necessity utility of second line / advanced tools (28,6%) but it does not entail the risk of major complications and procedure related death. 5. Difficulties in extracting HBP leads comparable to those encountered in the extraction of LVP leads of similar age. 6. Survival after HBP and LVP lead extraction was comparable, but shorter than after removal of other leads.

A comparative analysis of conduction system pacing and biventricular pacing in patients undergoing atrioventricular node ablation: a systematic review and meta-analysis

Abstract Background Atrioventricular node ablation (AVNA) with concomitant permanent pacemaker implantation is a well-established management strategy for patients with atrial fibrillation demonstrating refractory and uncontrolled ventricular rates. Conduction system pacing (CSP) utilising His bundle pacing (HBP) or left bundle branch area pacing (LBBAP), has emerged as an alternative to conventional pacing (CP) (including right ventricular pacing (RVP) and biventricular pacing (BVP). The aims and objectives of this systematic review and meta-analysis is to provide a comprehensive summary and synthesis of clinical outcomes in the literature for CSP in comparison to BVP when facilitated with AVNA. Methods This study protocol was registered in the PROSPERO registry and the review was conducted as per the PRISMA guidelines. MEDLINE, EMBASE and Cochrane Library were searched for relevant studies from inception till January 11th, 2024. Results were synthesised using a random effects meta-analysis. Risk of bias (ROB) assessment was carried out with the RoB 2 and ROBINS-I tool. Results From a total of 259 references identified, 122 full texts were assessed and 5 studies (1 randomised control trial, 2 prospective observational studies, and 2 retrospective observational studies) were included in the review. A total of 738 patients (HBP-294 and LBBAP-444) received CSP and BVP implantation with AVNA, respectively. All devices were implanted successfully with a cumulative total of 4 patients in the HBP population demonstrating acute threshold hold increase following AVN. There was no loss of capture on follow-up in either treatment groups. HBP resulted in a narrower QRSd with a reduction of -35.3 ms (95% confidence interval [CI] -63.8 to -6.78; P<0.05; I2=96.6%) vs BVP. For left ventricular ejection fraction (LVEF), a weighted mean increase of 3.50% (95% CI -0.55%-7.54%; P=0.02, I2=65.8%) was observed following HBP implantation in comparison to BVP (Figure 1). Furthermore, LBBAP also demonstrated a weighted mean increase in LVEF of 6.02% (95%CI -4.05%-16.1%; P<0.05; I2=90.7%) in comparison to BVP. The mean NYHA score was reduced by -0.54 (95% CI -1.07 to -0.02; P=0.05, I2=65.5%) after HBP implantation when compared to BVP. There was a cumulative total of 45 and 65 events of heart failure associated hospitalisation in the HBP and BVP, respectively (OR 0.69; 95% CI 0.19-1.18; P=0.99, I2 =0.00). Conclusion To our knowledge, this is the first methodologically robust systematic review and meta-analysis evaluating the outcomes of CSP with AVNA. Overall, both CSP modalities demonstrated feasibility and application as an effective CRT alternative to facilitate AVNA along with a narrower QRSd ,improved LVEF and trend of better clinical outcomes. While these preliminary findings are promising, further RCTs will be necessary to establish the long-term efficacy and safety of this approach.

Conduction-System pacing Italian Network Group (C-SING): insights from a Nationwide Multicenter Observational Study

Abstract Background/Introduction Conduction system pacing (CSP), encompassing His bundle pacing (HBP) and left bundle branch area pacing (LBBAP), has gained prominence in treating bradycardia and heart failure in recent years. Despite its increasing utilization, data on real-world adoption of CSP are limited. Purpose The C-SING study aimed at assessing patient characteristics, implant success, procedural details, and safety of CSP when performed in routine clinical practice. Methods Periprocedural data from 27 experienced CSP centers across Italy were collected on patients undergoing CSP implantation for various indications between January 2021 and January 2024. Results The study comprised 1,317 patients (median age 78 years [interquartile range, 71-83], male 66.2%). Leading indications included atrioventricular (AV) block (40.8%), sinus node dysfunction (12.1%), atrial fibrillation with bradycardia (9.7%), AV node ablation (9.5%), and heart failure (12.5%). Pacemakers were implanted in 77.3% of patients, cardiac resynchronization devices in 21.7%, and implantable cardioverter-defibrillators in 1.0%. Stylet-driven and lumenless CSP leads were utilized in 64.7% and 35.3% of procedures, respectively. Final 12-lead ECG assessment revealed LBBAP capture in 88.7% patients, HBP in 8.4% (selective 4.2%, non-selective 4.2%), and no CSP capture in 3.0%, resulting in a 97.0% CSP lead implantation success rate. In patients with LBBAP, predominant capture types were left bundle branch pacing (19.6%), left posterior fascicular pacing (19.2%), and left septal fascicular pacing (14.8%). Comparing HBP to LBBAP, the latter showed shorter procedural time (60 minutes [45-80] vs. 70 minutes [60-95], p=0.003), but similar fluoroscopy time (6.0 minutes [3.3-10.8] vs. 6.1 minutes [4-10], p=0.735). Paced QRS duration was longer in LBBAP (118 ms [105-130]) compared to HBP (110 ms [101-122], p<0.001). LBBAP showed lower capture thresholds (0.6 V [0.5-0.9] @0.4 ms vs. 0.8 V [0.5-1.5] @1.0 ms, p<0.001) and higher R-wave sensing (10.7 mV [8-16] vs. 4.5 mV [2.4-9.9], p<0.001). The rate of periprocedural complications was higher in patients with LBBAP than HBP (7.3% vs. 1.8%, p=0.03), with the most frequent events being intraprocedural perforation into the left ventricular cavity during lead screwing (2.6%) and CSP lead dislodgment before hospital discharge (1.4%). These occurrences necessitated lead repositioning without additional complications. Conclusion CSP demonstrated feasibility as a primary pacing strategy for various indications in a real-world, multicenter setting. LBBAP, more frequently used than HBP, exhibited shorter procedural time and superior acute electrical parameters. LBBAP revealed a higher rate of minor procedural complications than HBP. Further investigations, supported by additional long-term outcome data, are essential to comprehensively assess CSP performance.

His bundle pacing is continually relevant for patients with atrial fibrillation and bradycardia without prior atrioventricular nodal ablation, data from mid-term follow-up.

In patients with atrial fibrillation (AF) and symptomatic bradycardia, His Bundle pacing (HBP) is used to achieve an appropriate heart rate and physiological depolarization of the left ventricle (LV). We aimed to evaluate the impact of HBP on LV function in two different populations: normal LV ejection fraction (LVEF) and low LVEF (<50%). Patients who received HBP as de novo therapy or as an upgrade were divided into two groups based on initial LVEF, followed by echocardiographic and device monitoring. One hundred and twenty three patients (aged 76.0 [69.2-79.8] years, 74.0% men) with AF and bradycardia received HBP and completed follow-up with a median of 6.2 months (6.0-8.0). LV function remained unchanged in initially normal LV function patients (65 participants, LVEF 59.0% [55.0 - 62.0] vs. 58.0% [55.0-63.0]). In patients with low LVEF (58 participants), there was an increase in LVEF (37.5% [30.0-43.0] vs. 44.0% [35.0-50.0]; p < 0.0001), reduction of indexed LV end-systolic volume (62.4 [20.7] ml vs. 51.5 [21.5] ml; p = 0.001) and indexed LV end-diastolic volume (97.5 [26.2] ml vs. 88.1 [25.1] ml; p = 0.009), and improvement in the New York Heart Association class (2.3 [0.71] to 1.6 [0.9]; p < 0.0001). With permanent HBP, patients with AF and bradycardia and without prior atrioventricular nodal ablation did not experience LV systolic function deterioration. Those with reduced baseline LVEF experienced improvements in LV function and its reverse remodeling at the mid-term follow-up.

His Bundle Pacing and Left Bundle Branch Pacing in Patients with Heart Failure.

His bundle pacing (HBP) and left bundle branch pacing (LBBP) are emerging therapies for patients with heart failure and conduction disorders, offering potential advantages over traditional pacing methods. These approaches aim to restore physiological conduction and improve cardiac function more effectively. This study aims to evaluate the efficacy and safety of HBP and LBBP in patients with heart failure and conduction disturbances, comparing these techniques to conventional pacing. A comprehensive review of recent studies and clinical trials was conducted, focusing on the performance of HBP and LBBP in improving cardiac function, reducing QRS duration, and enhancing overall patient outcomes. The analysis includes data on clinical efficacy, procedural safety, and long-term benefits associated with these pacing modalities. Both HBP and LBBP have demonstrated significant improvements in cardiac function and clinical outcomes compared to conventional pacing. HBP effectively restores physiological conduction with improved synchronization and a reduction in QRS duration. LBBP has shown enhanced left ventricular activation, leading to better overall cardiac performance. Both techniques have been associated with a lower incidence of complications and a higher success rate in achieving optimal pacing thresholds. HBP and LBBP offer promising alternatives to traditional pacing for patients with heart failure and conduction disorders. These advanced pacing strategies provide superior clinical outcomes and improved cardiac function with reduced risk of complications. Further research and clinical trials are needed to fully establish the long-term benefits and safety profiles of these techniques in diverse patient populations.

His bundle pacing in a patient with complete atrioventricular block and congenitally corrected transposition of the great arteries: potential of the use of extended reality and cardiac electrical activity projected into 3D heart model.

His bundle pacing in a patient with complete atrioventricular block and congenitally corrected transposition of the great arteries: potential of the use of extended reality and cardiac electrical activity projected into 3D heart model.

Experience with transvenous lead extraction of His bundle pacing leads.

Experience with transvenous lead extraction of His bundle pacing leads.

Left ventricular volumes and function in successful and failed His-BundLe Pacing. A comparative prospective study.

Initial data suggest that His Bundle Pacing (HBP) could preserve long-term cardiac structure and function better than Right Ventricular Pacing (RVP), but evidence is limited. We studied consecutive patients with baseline ejection fraction (EF) ≥ 50% who underwent HBP attempt, either successful (HBP group) or failed (RVP group). Two-dimensional (2D) and three-dimensional (3D) echocardiography were carried out at baseline and after 6 months of ventricular pacing burden > 20%. Among 68 patients, 40 underwent successful HBP, and 28 RVP. The HBP and RVP groups did not differ for age, sex and pacing indication. At baseline, the HBP and RVP groups did not differ for 2D EF (62% vs. 62%), 3D EF (60% vs. 63%), 2D (-19% vs. -19%) and 3D global longitudinal strain (GLS) (-15% vs. -16%). After 6 months, 2D EF (-3.86%) and 3D EF (-5.71%) significantly decreased in the RVP group and did not change in the HBP group (p for interaction .006 and <.001, respectively). 2D GLS (3.08%) and 3D GLS (2.22%) significantly increased in the RVP group, but did not change in the HBP group (p for interaction .013 and <.016, respectively). Pacing induced cardiomyopathy (PICM) (EF drop ≥ 10% and EF < 50%) occurred in 14% (RVP) versus 0% (HBP) of patients (p = .025). Successful HBP was superior to RVP in preserving LV systolic function despite a high ventricular pacing burden, and was less frequently associated with PICM.

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.

Conduction system pacing compared with biventricular pacing for cardiac resynchronization therapy in patients with heart failure and mildly reduced left ventricular ejection fraction: Results from International Collaborative LBBAP Study (I-CLAS) Group

BackgroundCardiac resynchronization therapy (CRT) is a guideline-recommended therapy in patients with heart failure with mildly reduced ejection fraction (HFmrEF, 36%–50%) and left bundle branch block or indication for ventricular pacing. Conduction system pacing (CSP) using left bundle branch area pacing or His bundle pacing has been shown to be a safe and physiologic alternative to biventricular pacing (BVP). ObjectiveThe aim of this study was to compare the clinical outcomes between BVP and CSP for patients with HFmrEF undergoing CRT. MethodsConsecutive patients who underwent BVP or CSP with HFmrEF between January 2018 and June 2023 at 16 international centers were included. The primary outcome was the composite end point of time to death or heart failure hospitalization (HFH). Secondary end points included change in left ventricular ejection fraction (LVEF) and individual end points of death and HFH. ResultsA total of 1004 patients met inclusion criteria: BVP, 178; CSP, 826 (His bundle pacing, 154; left bundle branch area pacing, 672). Mean age was 73 ± 13 years; female, 34%; and LVEF, 42% ± 5%. Paced QRS duration in CSP was significantly narrower compared with BVP (129 ± 21 ms vs 144 ± 19 ms; P < .001). LVEF improved during follow-up in both groups (49% ± 10% vs 48% ± 10%; P = .32). CSP was independently associated with significant reduction in the primary end point of time to death or HFH compared with BVP (22% vs 34%; hazard ratio, 0.64; 95% confidence interval, 0.43–0.94; P = .025). ConclusionCSP was associated with improved clinical outcomes compared with BVP in this large cohort of patients with HFmrEF undergoing CRT. Randomized controlled trials comparing CSP with BVP will be necessary to confirm these results.

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

BackgroundConduction 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. ObjectiveThis 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. MethodsMedicare 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. ResultsCSP 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. ConclusionDC 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.

First experience of His bundle pacing in pediatric patients

First experience of His bundle pacing in pediatric patients

Helix breakage during left bundle pacing area implantation.

A left bundle pacing stimulation pacemaker was implanted using stylet driver lead. The screw incarceration occurred after positioning of the lead. The screw rupture occurred during lead retraction; the distal portion of the screw remained incarcerated at the interventricular septum.

Clinical outcomes of conduction system pacing compared to biventricular pacing in patients with mid-range ejection fraction.

There is a paucity of data comparing conduction system pacing (CSP) to biventricular pacing (BiVP) in patients with heart failure (HF) with mid-range left ventricular ejection fraction (LVEF). Compare the clinical outcomes of patients with mid-range LVEF undergoing CSP versus BiVP. Patients with mid-range LVEF (> 35 to 50%) undergoing CSP or BiVP were retrospectively identified. Lead performance, LVEF, HF hospitalization, and clinical composite outcome including upgrade to cardiac resynchronization therapy and mortality were compared. A total of 36 patients (20 BiVP, 16 CSP--14 His bundle pacing, 4 left bundle branch area pacing) were analyzed. The mean age was 73 ± 15, 44% were female, and the mean LVEF was 42 ± 5%. Procedural and fluoroscopy time was comparable between the two groups. QRS duration was significantly shorter for the CSP group compared to the BiVP group (P < 0.001). During a mean follow-up of 47 ± 36months, nosignificant differences were found in thresholds or need for generator change due to early battery depletion. LVEF improved in both groups (41.5 ± 4.5% to 53.9 ± 10.9% BiVP, P < 0.001; 41.6 ± 5.3% to 52.5 ± 8.3% CSP, P < 0.001). There were no significant differences in HF hospitalizations (P = 0.71) or clinical composite outcomes (P = 0.07). Among patients with HF with moderately reduced ejection fraction, CSP appears associated with similar improvements in LVEF and had similar clinical outcomes as BiVP in mid-term follow-up.

Lumenless and Stylet-Driven Leads for Left Bundle Branch Area Pacing: Materials, Techniques, Benefits, and Trade-Offs of the Two Approaches.

Left bundle branch area pacing (LBBPa) is an innovative technique for physiological pacing. Compared with His bundle pacing, LBBPa provides better pacing thresholds, lower rates of macrodislodgment, and a reliable strategy for cardiac resynchronization. LBBPa traditionally employs lumenless leads (LLL), which are characterized by small lead bodies and a fixed helix design. These features guarantee stability, avoid helix retraction, and facilitate easier septal penetration, all contributing to an advantageous learning curve. On the other hand, stylet-driven pacing leads (SDL) have shown comparable success rates related to lumenless pacing leads, although they carry risks of helix retraction and lead fracture. SDL have been increasingly employed with favorable results, as they provide good maneuverability and support during implantation with continuous monitoring of ECG-paced morphology. Different manufacturers are offering a variety of SDL, and new dedicated tools are being developed to simplify lead implantation. In this review, we examine the procedural techniques, advantages, and limitations of the most commonly used pacing leads and tools for LBBPa, and we summarize the complications associated with both lumenless leads (LLL) and stylet-driven leads (SDL).

Is Conduction System Pacing Going to Be the New Gold Standard for Cardiac Resynchronization Therapy?

The current gold standard in device therapy for advanced heart failure (HF), which has been firmly established in HF management for more than 25 years, is classical biventricular pacing (BiV-CRT). In the last decade, a new pacing modality called conduction system pacing (CSP) has emerged as a variant for advanced cardiac device therapy. It provides pacing with preserved intrinsic cardiac activation by direct stimulation of the specific cardiac conduction system. The term CSP integrates the modalities of HIS bundle pacing (HBP) and left bundle branch area pacing (LBBAP), both of which have provided convincing data in smaller randomized and big non-randomized studies for the prevention of pacemaker-induced cardiomyopathy and for providing effective cardiac resynchronization therapy in patients with classical CRT-indication (primary approach or after failed CRT). Recent American guidelines proposed the term "cardiac physiological pacing" (CPP), which summarizes CSP including left ventricular septal pacing (LVSP), a technical variant of LBBAP together with classical BiV-CRT. The terms HOT-CRT (HIS-optimized CRT) and LOT-CRT (LBBP-optimized CRT) describe hybrid technologies that combine CSP with an additional coronary-sinus electrode, which is sometimes useful in patients with advanced HF and diffuse interventricular conduction delay. If CSP continues providing promising data that can be confirmed in big, randomized trials, it is likely to become the new gold standard for patients with an expected high percentage of pacing (>20%), possibly also for cardiac resynchronization therapy. CSP is a sophisticated new treatment option that has the potential to raise the term "cardiac resynchronization therapy" to a new level. The aim of this review is to provide basic technical, anatomical, and functional knowledge of these new pacemaker techniques in order to facilitate the understanding of the different modalities, as well as to provide an up-to-date overview of the existing randomized and non-randomized evidence, particularly in direct comparison to right ventricular and classical biventricular pacing.

Conduction system pacing upgrade versus biventricular pacing on pacemaker-induced cardiomyopathy: a retrospective observational study.

Objective: The feasibility of the conduction system pacing (CSP) upgrade as an alternative modality to the traditional biventricular pacing (BiVP) upgrade in patients with pacemaker-induced cardiomyopathy (PICM) remains uncertain. This study sought to compare two modalities of CSP (His bundle pacing (HBP) and left bundle branch pacing (LBBP)) with BiVP and no upgrades in patients with pacing-induced cardiomyopathy. Methods: This retrospective analysis comprised consecutive patients who underwent either BiVP or CSP upgrade for PICM at the cardiac department from 2017 to 2021. Patients with a follow-up period exceeding 12months were considered for the final analysis. Results: The final group of patients who underwent upgrades included 48 individuals: 11 with BiVP upgrades, 24 with HBP upgrades, and 13 with LBBP upgrades. Compared to the baseline data, there were significant improvements in cardiac performance at the last follow-up. After the upgrade, the QRS duration (127.81 ± 31.89 vs 177.08 ± 34.35ms, p < 0.001), NYHA class (2.28 ± 0.70 vs 3.04 ± 0.54, p < 0.05), left ventricular end-diastolic diameter (LVEDD) (54.08 ± 4.80 vs 57.50 ± 4.85mm, p < 0.05), and left ventricular ejection fraction (LVEF) (44.46% ± 6.39% vs 33.15% ± 5.25%, p < 0.001) were improved. There was a noticeable improvement in LVEF in the CSP group (32.15% ± 3.22% vs 44.95% ± 3.99% (p < 0.001)) and the BiVP group (33.90% ± 3.09% vs 40.83% ± 2.99% (p < 0.001)). The changes in QRS duration were more evident in CSP than in BiVP (56.65 ± 11.71 vs 34.67 ± 13.32, p < 0.001). Similarly, the changes in LVEF (12.8 ± 3.66 vs 6.93 ± 3.04, p < 0.001) and LVEDD (5.80 ± 1.71 vs 3.16 ± 1.35, p < 0.001) were greater in CSP than in BiVP. The changes in LVEDD (p = 0.549) and LVEF (p = 0.570) were similar in the LBBP and HBP groups. The threshold in LBBP was also lower than that in HBP (1.01 ± 0.43 vs 1.33 ± 0.32V, p = 0.019). Conclusion: The improvement of clinical outcomes in CSP was more significant than in BiVP. CSP may be an alternative therapy to CRT for patients with PICM. LBBP would be a better choice than HBP due to its lower thresholds.