Apical Pacing Research Articles

Effects of apical right ventricular pacing on right ventricular and left ventricular mechanics in patients with preserved systolic function: 2D speckle tracking assessment.

Effects of apical right ventricular pacing on right ventricular and left ventricular mechanics in patients with preserved systolic function: 2D speckle tracking assessment.

Abstract 10991: Incidence of Pacing-Induced Cardiomyopathy in Leadless and Traditional Pacemakers: A Retrospective Analysis of 198 Patients

Introduction: Transvenous pacemaker (TVP) with right ventricular (RV) apical pacing over 40% has been associated with a 17-25% risk of Pacing-Induced Cardiomyopathy (PICM), defined as a decrease in ejection fraction (EF) by 10% or more. It’s been postulated that a septally placed Leadless Pacemaker (LP) causes less risk of PICM, but the exact incidence is unknown. Methods: We performed a single-center retrospective analysis of adults who received an LP or TVP between January 1, 2014 and April 1, 2022 and had echocardiograms before and after the pacemaker. This study’s outcomes were the RV pacing percentage, change in EF, the need for cardiac resynchronization therapy (CRT) upgrade, and follow-up duration. A Wilcoxon rank-sum test calculated the change in EF. RV time, defined as the duration from pacemaker to echocardiogram in months multiplied by the RV pacing percentage, served as a surrogate for how long the RV was paced. Results: A total of 614 patients were screened and 198 patients were included in the study, where 72 received LP and 126 received TVP. The median follow-up was 480 days. The average of the reported 161 patients with RV percentage pacing for LP was 63.43% and TVP was 71.30% (p=0.14). The incidence of PICM and CRT upgrade in the LP group was 44% and 9.7% in LP and TVP was 37% and 9.5% in TVP (p=0.3 and p>0.9), respectively. After accounting for age, age, sex, LP vs TVP, atrioventricular nodal ablation, RV pacing percentage, and follow-up duration, univariate analysis showed that RV time was significantly different between pacemakers (LP 1,353.97 ± 1,420.56 months vs TVP 926.47 ± 1,395.17 months, p=0.009), but not with CRT (No CRT 1,211.37 ± 1,447.45 months vs CRT 919.34 ± 1,199.54 months, p=0.5). Conclusions: This analysis demonstrated that the incidence of PICM was high in both groups (LP 44% vs TVP 37%). Despite significantly more RV time in patients with LP, there was no difference in CRT upgrade.

Abstract 13086: Mid-Term Feasibility of Left Bundle Branch Area Pacing With Standard Stylet-Driven Pacing Leads and Predictors of Success: A Multicenter Center Experience

Introduction: Conventional right ventricular apical pacing can cause electrical-mechanical dyssynchrony. For this reason, physiological pacing was considered and became the background for the development of his bundle pacing (HBP). Recently, left bundle branch area pacing (LBBAP), which overcomes the shortcomings of HBP, has been implemented. Hypothesis: Initially, LBBAP was achieved through a lumen-less lead, and it has been reported that LBBAP using a standard stylet-driven lead (SDL) is also available. The purpose of this study is to establish the feasibility and mid-term outcome of LBBAP using SDL, and to investigate the predictors of success. Methods: This study enrolled a total of 119 patients who underwent LBBAP from December 2020 to February 2022. LBBAP was performed with a 5.6Fr stylet-driven pacing lead with an extendable helix (Solia S60, Biotronik, SE & Co, KG). We analyzed the initial outcomes of the procedure, including the success rate and complications, and identified predictive factors that affect them. lead parameters were assessed in follow up. Results: Total success rate of lead implantation of LBBAP with conventional stylet-driven lead was 95.8% for entire period and showed increase in success rate as the number of procedures increased. In the multivariate analysis, The larger the RA size, the greater the number of trials (Estimates = 1.770 [1.10 - 2.44], p = <0.001) and the smaller the RV size, the greater the number of trials (Estimates = -0.923 [-1.64 - -0.21], p = 0.012). The mean thresholds at implant, 2 months, 6 months were 0.90 ± 0.80 V at 0.5 ms, 0.80 ± 0.16 V at 0.5 ms, and 0.87 ± 0.28 V at 0.5 ms respectively in total period. Conclusions: LBBAP with conventional stylet-driven lead is a feasible and safe pacing modality. It has a high success rate and fewer complications, satisfied and stable lead parameters in intermediate-term observations.

Risk of pacing-induced cardiomyopathy in patients with high-degree atrioventricular block – comparison between right ventricular pacing sites using computed tomography

Abstract Background Right ventricular (RV) pacing may induce significant left ventricular (LV) dyssynchrony resulting in pacing-induced cardiomyopathy (PICM). LV activation sequence is affected by RV pacing site and previous studies suggest that RV septal pacing may be superior compared to traditional RV apical pacing. However, results are conflicting and randomized controlled trials have failed to show clear benefits from RV septal pacing. Traditionally, studies have applied fluoroscopy to determine RV lead implantation site. However, locating pacing site using this method is known to be inaccurate and poorly reproducible compared with cardiac computed tomography (CT). The purpose of our study was to evaluate the association between RV pacing site determined by cardiac CT and risk of PICM. Methods We retrospectively included 153 patients with pre-implant LV ejection fraction (LVEF) ≥50% who underwent fluoroscopy-guided dual chamber pacemaker implantation due to high-degree atrioventricular block between March 2012 and May 2020. All patients attended a follow-up visit including cardiac CT and transthoracic echocardiography. RV lead position was evaluated from CT dividing the RV into three segments: apical, septum or free wall (Figure 1). Furthermore, RV lead position estimated by the implanting physician, using fluoroscopy during pacemaker implantation, was retrieved from medical records. The primary endpoint was PICM defined as ≥10% decrease in LVEF from time of pacemaker implantation to follow-up, resulting in LVEF <50%. Results Mean duration of follow-up was 3.7 years (range 2.1–8.7). The implanting physician estimated 131 (85.6%) leads to be located septal, 5 (3.3%) located non-septal and 17 (11.1%) were unknown. Based on CT, 48 (31.4%) leads were located septal and 105 (68.6%) were located non-septal of which 31 were located on the free wall (20.4%). With CT as the golden standard, 47 (35%) leads were estimated correctly during fluoroscopy-guided implantation. No significant differences between patient characteristics in the CT-estimated septal and non-septal groups were observed except for ischemic heart disease (P=0.05) (Table 1). There were 16 (33.3%) patients in the septal group who developed PICM compared to 31 (29.5%) in the non-septal group (P=0.6). Adjusting for ischemic heart disease did not change this result. In the septal group, the change in LVEF from baseline to follow-up was −9.0±10.4% compared to −7.5±9.1% in the non-septal group (P=0.4). Conclusion In total 31% developed PICM despite having a normal pre-implant LVEF with no observed difference between RV septal and non-septal pacing. With CT as the golden standard, RV leads were inaccurately located during fluoroscopy-guided pacemaker implantation with only 35% being located correctly. Misclassification of pacing sites in previous studies may have contributed to the inconsistent results. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Svend Andersens FondKarl G Andersens Fond

The interplay of sex-specific electrophysiology and repolarization heterogeneity governs ventricular arrhythmia sustainability in women

Abstract Background The role of sex-specific electrophysiology in the development of lethal ventricular arrhythmia is poorly understood. Since female ventricles have a longer action potential duration (APD) than male ventricles, we hypothesized that female hearts are more vulnerable to sustained ventricular arrhythmia in the presence of known arrhythmogenic substrates. Purpose To determine if prolonged APD in females leads to sustained ventricular arrhythmia in the presence of left ventricular (LV) hypertrophy, diffuse fibrosis, and repolarization heterogeneity. Methods Magnetic resonance imaging (MRI) data were used to develop computational biventricular models of two aortic stenosis patients (male, 54 years; female, 64 years) before (LV hypertrophy) and 3 months after (regressed LV hypertrophy) aortic valve replacement (AVR). These patients were chosen since they exhibit reduced LV mass, less fibrosis, and no ventricular arrhythmias after AVR. The models were assigned sex-specific cellular electrophysiology and an apicobasal repolarization gradient derived from human data. Simulations of apical pacing with a cycle length (CL) of 750 ms were performed while APD at 90% repolarization (APD90) and repolarization time (activation time + APD90) were calculated. Reentrant arrhythmia was induced by rapidly pacing the LV with a 2 mm wide apicobasal line electrode at CL≤265 ms. The simulations were repeated in the presence of diffuse myocardial fibrosis derived from the MRI patient data, and repeated again with an apicobasal repolarization gradient reduced by ≈35%. Ventricular mass was calculated as the product of model volume and myocardial density. Results In hypertrophic ventricles with default apicobasal repolarization gradient, rapid pacing led to reentry that lasted longer in the female (>25 s) than in the male (1.0 s) ventricles. The duration of reentry increased in the presence of fibrosis in the male ventricles (male: 6.6 s; female >25 s) and decreased in the female ventricles when the apicobasal repolarization gradient was reduced (Figure). Sustained reentry (>25 s) was not observed in the ventricles with regressed hypertrophy, regardless of the presence of fibrosis or repolarization gradient. Average APD90 was longer in the female ventricles both before (male: 267±35 ms; female: 318±34 ms) and after (male: 272±35 ms; female: 328±38 ms) AVR. The female heart had lower myocardial mass than the male heart both before (280 vs. 406 g) and after AVR (227 vs. 310 g). Conclusion Longer APD and steeper apicobasal repolarization gradients in hypertrophic female ventricles resulted in sustained arrhythmia, despite their lower mass when compared to males. The absence of sustained reentry in the post-AVR models indicates a potential electrophysiological benefit of AVR and encourages future clinical studies to quantify sex-specific differences in spatial repolarization heterogeneity. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Union's Horizon 2020 research and innovation program under the ERA-NET co-fund action No. 680969 with ANR (ERA-CVD SICVALVES) and Agence Nationale de la Recherche

Cardiomyopathy associated with right ventricular apical pacing – systematic review and meta-analysis

Abstract Aims Bradyarrhythmias are potentially life threatening medical conditions. The most widespread type of treatment of slow rhythms is artificial ventricular pacing. From the inception of the idea of artificial pacing, ventricular lead was located in the apex of the right ventricle. Right ventricular pacing (RVP) was thought to have deteriorating effect on left ventricular systolic function. The aim of this study was to systematically assess results of randomized controlled trials of the right ventricular pacing on left ventricular ejection fraction (LVEF). Methods We systematically searched the Cochrane Central Register of Controlled Trials, PubMed, and EMBASE databases for studies evaluating the influence of the RVP on the LVEF. Pooled mean difference (MD) with a 95% confidence interval (CI) was estimated using a random effect model. Results 15 randomized controlled trials (RCTs) comprising 951 patients were included. The mean follow-up in the included studies ranged between 6 to 24 months. In our meta-analysis, RV pacing was associated with statistically significant (MD 2.91; 95% confidence interval (CI): 1.07–4.75) left ventricular systolic function impairment measured by LVEF. Conclusion Our meta-analysis confirms, that the right ventricular pacing is associated with progressive deterioration of the left ventricular systolic function. Funding Acknowledgement Type of funding sources: None.

Impact of right ventricular lead position on left ventricular functions and early remodeling in permanent single- and dual-chamber pacemakers.

Right ventricular (RV) apical pacing can induce both interventricular dyssynchrony and intraventricular dyssynchrony. Mechanical dyssynchrony after long-term RV apical pacing is associated with reduced left ventricular (LV) systolic function and deterioration in functional capacity. We aimed to identify the short-term effects of the pacemaker RV lead position on remodeling of LV systolic functions. The study included 30patients who presented with an indication of permanent pacing and who underwent permanent single- or dual-chamber pacemaker insertion: 15patients with RV apical pacing (RV apex), and 15patients with non-apical pacing (mid-septal). The two-dimensional (2D)speckle tracking imaging technique was used for quantification of global longitudinal function of the left ventricle and dyssynchrony evaluation before pacemaker implantation and after a3-month follow-up. At the 3‑month follow-up, post-pacing 2Dspeckle tracking echocardiography revealed impairment of global longitudinal strain in all patients and intraventricular dyssynchrony was significantly increased in the apical location compared with the non-apical location (radial dyssynchrony: 108.67 ± 11.68 ms vs. 80.53 ± 8.17 ms, p < 0.001) with a greater difference (50.53 ± 13.30 ms) in the apical location than in the non-apical location (29.87 ± 6.64 ms, p < 0.001). In the short-term follow-up, 2Dspeckle tracking echocardiography showed more radial dyssynchrony in the apical location than in the non-apical location of RV lead. The RV septal pacing is abetter alternative in terms of less dyssynchrony compared to RV apical pacing. Older age, higher percentage of pacing, and device type are prognostic factors for development of pacemaker-induced cardiomyopathy.

Comparisons of electrophysiological characteristics, pacing parameters and mid- to long-term effects in right ventricular septal pacing, right ventricular apical pacing and left bundle branch area pacing

BackgroundAs a near-physiological pacing innovation, left bundle branch area pacing (LBBAP) has drawn much attention recently. This study was aimed to investigate the electrophysiological characteristics, unipolar/bipolar pacing parameters and mid- to long-term effects and safety of three different pacing methods and identify possible predictors of adverse left ventricular remodeling.MethodsNinety-two patients were divided into the LBBAP group, right ventricular septal pacing (RVSP) group and right ventricular apical pacing (RVAP) group. Baseline information, electrophysiological, pacing and echocardiographic parameters were collected.ResultsThe three pacing methods were performed with a similar high success rate. The paced QRSd was significantly different among the LBBAP, RVSP and RVAP groups (105.93 ± 15.85 ms vs. 143.63 ± 14.71 ms vs. 155.39 ± 14.17 ms, p < 0.01). The stimulus to left ventricular activation time (Sti-LVAT) was the shortest in the LBBAP group, followed by the RVSP and RVAP groups (72.80 ± 12.07 ms vs. 86.29 ± 8.71 ms vs. 94.14 ± 10.14 ms, p < 0.001). LBBAP had a significantly lower tip impedance during the procedure and 3-month follow up as compared to RVSP and RVAP (p < 0.001). Higher bipolar captured thresholds were observed in LBBAP during the procedure (p < 0.001). Compared to the baseline values, there was a greater reduction in left ventricular end-diastolic dimension (LVEDD) in the LBBAP group (p = 0.046) and a significant enlargement in LVEDD in the RVAP group (p = 0.008). Multiple regression analysis revealed that the Sti-LVAT was a significant predictor of LVEDD at 12 months post-procedure. At the 24-h post-procedure, significant elevations were observed in the cTnI levels in LBBAP (p < 0.001) and RVSP (p < 0.05). More transient RBB injury was observed in LBBAP. But no significant difference was found in cardiac composite endpoints among three groups (p > 0.05).ConclusionsLBBAP demonstrated a stable captured threshold, a low tip impedance and a high R-wave amplitude during the 12-month follow-up. Left ventricular remodeling was improved at 12 months post-procedure through LBBAP. The Sti-LVAT was a significant predictor of left ventricular remodeling. LBBAP demonstrated its feasibility, effectiveness, safety and some beneficial electrophysiological characteristics during this mid- to long-term follow-up, which should be confirmed by further studies.

Hemodynamic Doppler echocardiographic evaluation of permanent His bundle and biventricular pacing after AV nodal ablation.

placing after atrioventricular (AV) nodal ablation for permanent atrial fibrillation (AF) may include cardiac resynchronization therapy (CRT) with either His bundle pacing (HBP) or biventricular pacing (BVP), or conventional single site right ventricular apical pacing (RVAP). To determine the relationship between pacing method and hemodynamic outcome, we used Doppler echocardiographic methods to evaluate left ventricular (LV) hemodynamics after AV nodal ablation and either HBP, BVP, or RVAP.Method20 patients were evaluated > 6 months after AV nodal ablation, 10 each with chronic HBP or BVP, and all with RVAP lead. Doppler echocardiography was used to measure 3 parameters indicative of CRT: 1) LV dP/dt, 2) the LV pre-ejection interval, and 3) myocardial performance index, relative to intra-patient RVAP.ResultsPrimary endpoint of LV dP/dt on average improved by > 17% with both HBP and BVP, compared to RVAP. HBP but not BVP, had improvement across all three parameters.ConclusionHBP provides LV electromechanical synchrony across multiple echo Doppler parameters. Both HBP and BVP were hemodynamically superior to RVAP following AV nodal ablation.

The jugular approach for leadless pacing: A novel and safe alternative.

To evaluate safety of leadless pacemaker implantation through the internal jugular vein in a larger cohort with longer follow-up. Moreover, feasibility of non-apical pacing as well as relation between pacing site and QRS duration were assessed. Eighty Two consecutive patients, who received a leadless pacemaker though the internal jugular vein, were included. Electrical parameters were measured at regular follow-up and any complications were registered. Paced QRS interval was compared for three pacing sites, RVOT, RV mid septum, and RV apical septum. In all patients, the leadless pacemaker was implanted successfully. In 69 patients, the device was implanted in a non-apical position. In 71% of cases, the device could be deployed at first attempt. The median fluoroscopy time was 4.4 min (range 0.9-51) The paced QRS interval was significantly narrower for non-apical pacing sites compared to apical pacing si 156 vs. 179ms. p=.04, respectively. During mean follow-up of 16 months (range 0-43 months), electrical parameters remained stable. Two complications occurred, which could be resolved during the implant procedure. There were no access site related complications. The jugular approach for leadless pacemaker implantation is feasible and may avoid vascular complications. It facilitates non-apical positioning of leadless pacemakers leading to a narrower paced QRS interval. The jugular approach allows for immediate post procedural ambulation.

The Effect of Segmentation Variability in Forward ECG Simulation.

Segmentation of patient-specific anatomical models is one of the first steps in Electrocardiographic imaging (ECGI). However, the effect of segmentation variability on ECGI remains unexplored. In this study, we assess the effect of heart segmentation variability on ECG simulation. We generated a statistical shape model from segmentations of the same patient and generated 262 cardiac geometries to run in an ECG forward computation of body surface potentials (BSPs) using an equivalent dipole layer cardiac source model and 5 ventricular stimulation protocols. Variability between simulated BSPs for all models and protocols was assessed using Pearson's correlation coefficient (CC). Compared to the BSPs of the mean cardiac shape model, the lowest variability (average CC = 0.98 ± 0.03) was found for apical pacing whereas the highest variability (average CC = 0.90 ± 0.23) was found for right ventricular free wall pacing. Furthermore, low amplitude BSPs show a larger variation in QRS morphology compared to high amplitude signals. The results indicate that the uncertainty in cardiac shape has a significant impact on ECGI.

The history of cardiac pacing in the young and a look to the future.

The purpose of this review is to explore the historical and serendipitous events that led to the creation of modern-day pacemakers. In addition, this review will explore how contemporary conduction site-specific pacing has overcome some of the deleterious effects from historical chronic right ventricular apical pacing. Recently, there have been tremendous advances in not just the lead design but the tools required to promote more physiologic pacing. Although cardiac resynchronization pacing has been around for nearly 2 decades, this review also introduces and discusses the early results of His-bundle pacing and left bundle branch pacing and some of the potential applicability of this technology for our children. Pacemakers have evolved significantly in the last 30 years through collaborative partnerships between physicians and engineers. The future of cardiac pacing is bright compared to the field of electrotherapy 50 years ago. Future iterations of pacemakers must consider unusual anatomy and growing children. Pediatric patients contribute to a small percentage of the overall device volume, but the majority of these patients will have a pacemaker for life. We need to be proactive and consider what are the best short and long-term solutions for this cohort.

Mobile Cardiac Acoustic Monitoring System to Evaluate Left Ventricular Systolic Function in Pacemaker Patients.

The mobile cardiac acoustic monitoring system is a promising tool to enable detection and assist the diagnosis of left ventricular systolic dysfunction (LVSD). The objective of the study was to evaluate the diagnostic value of electromechanical activation time (EMAT), an important cardiac acoustic biomarker, in quantifying LVSD among left bundle branch pacing (LBBP) and right ventricular apical pacing (RVAP) patients using a mobile acoustic cardiography monitoring system. In this prospective single-center observational study, pacemaker-dependent patients were consecutively enrolled. EMAT, the time from the start of the pacing QRS wave to first heart sound (S1) peak; left ventricular systolic time (LVST), the time from S1 peak to S2 peak; and ECG were recorded simultaneously by the mobile cardiac acoustic monitoring system. LVEF was measured by echocardiography. A logistic regression model was applied to evaluate the association between EMAT and reduced EF (LVEF < 50%). A total of 105 pacemaker-dependent patients participated. The RVAP group (n = 58) displayed a significantly higher EMAT than the LBBP group (n = 47) (150.95 ± 19.46 vs. 108.23 ± 12.26 ms, p < 0.001). Pearson correlation analysis revealed a statistically significant negative correlation between EMAT and LVEF (p < 0.001). Survival analysis showed the sensitivity and specificity of detecting LVEF to be < 50% when EMAT ≥ 151 ms were 96.00% and 96.97% in the RVAP group. In LBBP patients, the sensitivity and specificity of using EMAT ≥ 110 ms as the cutoff value for the detection of LVEF < 50% were 75.00% and 100.00%. There was no significant difference in LVST with or without LVSD in the RVAP group (p = 0.823) and LBBP group (p = 0.086). Compared to LVST, EMAT was more helpful to identify LVSD in pacemaker-dependent patients. The cutoff point of EMAT for diagnosing LVEF < 50% differed regarding the pacing type. Therefore, the mobile cardiac acoustic monitoring system can be used to identify the progress of LVSD in pacemaker patients.

To go left or right? Driving towards the best direction in paediatric pacing.

Permanent pacing in children with isolated congenital complete atrioventricular block may cause left ventricular dysfunction. To prevent it, alternative pacing sites have been proposed: left ventricular epicardial or selective right ventricular endocardial pacing. To compare the functional outcome (left ventricular systolic function and synchrony) in paediatric patients with congenital complete atrioventricular block and left ventricular apical epicardial or right ventricular transvenous mid-septal pacing. Retrospective study. Epicardial leads were implanted by standard surgical technique, transvenous leads by 3D electroanatomic mapping systems. 3D mapping acquired 3D right ventricular local pacing map and defined the narrowest paced QRS site. 3D mapping guided screw-in bipolar leads on that ventricular site. Electrocardiogram (ECG) (QRS duration) and echocardiographic data (synchrony: interventricular mechanical delay, septal to posterior wall motion delay, systolic dyssynchrony index; contractility: global longitudinal strain, ejection fraction) were recorded. Data are reported as median [interquartile ranges]. p < 0.05 was significant. There were 19 transvenous systems (age 8.8 [6-14] years; right ventricular mid-septum) and 17 epicardial systems (0.04 [0.001-0.6] years; left ventricular apex). Post-implantation QRS significantly widened either in endocardial or in epicardial patients. Most patients reached 4-year follow-up. One-year and 4-year ejection fraction and global longitudinal strain were mostly within normal limits and did not show significant differences between the two groups and between the same endocardial/epicardial group. Synchrony parameters were within normal limits in the two groups. Left ventricular apical epicardial pacing and 3D mapping-guided right ventricular mid-septal pacing preserved left ventricular contractility and synchrony in children and adolescents with congenital complete atrioventricular block at short-/mid-term follow-up, without relevant significant differences between the two groups.

Apical versus septal pacing - can we chose the localization of ventricular lead in order to prevent upgrade to cardiac resynchronization therapy?

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Right ventricular apical pacing (RVAp) may be deleterious to ventricular function and hemodynamics due to pacing induced dyssynchrony. In the last decades, some studies showed that RVAp has been associated with heart failure, deterioration of left ventricular function and high mortality. Some patients (pts) may need, during the follow up (FUP), an upgrade to cardiac resynchronizaon therapy (CRT). New techniques have emerged such as RV lead implantation in the high septum or outflow RV tract (RVOT) and, more recently, His bundle/LB pacing. Purpose To compare the need for upgrade to CRT in patients with RVAp versus septal/RVOT pacing. Methods Retrospective single-center study of consecutive pts that implanted pacemakers in a tertiary center between January 1995 and December 2020. We collected data regarding pacing indication, RV pacing site (apex versus septum/RVOT) and need for an upgrade to CRT during follow up (FUP). Our primary endpoint was upgrade to CRT during the FU period. In the model, the impact of localization of the implanted lead on the survival free from upgrade was estimated assuming a neutral effect on mortality. Statistical analysis was performed using T-student test and logistic regression. Results We included 8761 pts, 60.2% (n=5275) were male, with a mean age of 76.5±10.7 years. The main indications for pacemaker implantation were (1) complete atrioventricular (AV) block (2239, 25.6%), (2) sick sinus syndrome (2211, 25.2%), (3) atrial fibrillation with AV block or bradycardia with significant pauses (17.4%) and (4) Mobitz II 2nd degree AV block (1467, 16.7%). RVAp was performed in 1746 (20%) patients and RVOT/septal pacing in 6933 patients (80%; RVOT in 657 (9,5%)). During FUP, 26 (1,5%) RVAp pts and 52 (0,8%) RVOT/septal pacing pts underwent upgrade to CRT, in a total of 78 pts (CRT-P in 54 patients and CRT-D in 24 patients). We observed that patients with RVAp had twice the risk of CRT upgrade during FUP (OR: 2,0 (IC 95% 1,25-3,21), p=0,004) when compared to patients with RVOT/septal pacing. Conclusions Patients with RVAp presented a 2-fold higher risk for upgrade to CRT when compared to patients with RVOT/septal pacing in our center. This retrospective analysis shows that lead implantation in the septum/RVOT should be preferred instead of the apex to reduce pacing induced dyssynchrony and need for CRT upgrade.

Short term outcomes of distal (ventricular) His bundle pacing: A single centre retrospective study

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Chronic right ventricular apical pacing can lead to pacing induced cardiomyopathy in a significant proportion of patients. Conduction system pacing may restore more physiological activation of the heart, and has recently been shown to have favourable outcomes in clinical trials. However there remains concern regarding the long-term outcomes due to lead displacement and high pacing thresholds. The most widely used technique in current practice is to pace the His bundle proximal to the tricuspid valve. Distal His bundle pacing has a number of advantages over proximal His pacing, including, lower capture thresholds, a more stable lead position, less far field atrial sensing and better spacing from the AV node in case ablation of this is required for AF rate control. Despite these, outcomes of distal His bundle pacing from the ventricular aspect are less well defined. Methods We performed a retrospective review of patients who underwent conduction system pacing between January 2020 and October 2021 at our centre. During this period all procedures were performed employing a distal His bundle pacing approach with the lead placed on the ventricular aspect of the tricuspid annulus. Data was collected at implant, follow-up at 1 month and then every 6 months. Results Out of 35 patients, 33 underwent successful His bundle pacing (acute success rate of 94%), 1 patient had left bundle branch pacing and another patient had an unsuccessful procedure. Mean age was 74 years, median LVEF 45% and median pre-implant QRS was 108ms. 80% of the cohort had a history of AF. The indications for pacing were as follows: AF - for pace &amp; ablate (60%); high grade AV block with narrow QRS and mild LVSD (17%); failed LV lead (14%); and other 9%. Mean procedure duration and fluoroscopy time were 78 minutes and 12.05 minutes, respectively. Median threshold at implant was 1.00V (IQR 0.719V). Selective His bundle pacing was achieved in 60% and non-selective in 34%. Mean follow-up duration was 150 days with median threshold at last f/up of 0.75V (IQR 0.750V). There were no acute procedural complications. 1 patient had a significant rise in threshold at follow-up and therefore required upgrade to CRT-P. Discussion Our data shows that distal His bundle pacing is a safe and effective technique for conduction system pacing. Thresholds appear stable at follow-up and failure rate was found to be comparable to biventricular pacing. We noted an initial learning curve for both implanter and physiologists with relatively poorer outcomes for the earlier cases. Longer term follow-up is ongoing, including functional assessment and follow-up to assess for remodelling with echocardiography. Prospective randomised trials are needed to compare conduction system pacing vs RV pacing in AF patients with HFpEF or mild LVSD undergoing AVN ablation, and vs biventricular pacing in the severe LVSD population.

Preliminary study on left bundle branch area pacing in children: Clinical observation of 12 cases.

Left bundle branch area pacing (LBBAP) maintains electrical and mechanical synchronization of the ventricles. It is a relatively physiological pacing mode, with low and stable pacing threshold and wider indications. LBBAP in children has been rarely reported. This study observed 12 children attempted LBBAP from January 2019 to January 2021 in the department of pediatric cardiology of Anzhen Hospital prospectively. Clinical data, pacing parameters, electrocardiograms, intracardiac electrograms, echocardiographic measurements and complications were recorded at implant and during follow-up. The 12 patients aged between 3 and 14 years old and weighted from 13 to 48 kg. Eleven patients were diagnosed with third-degree atrioventricular block and 1 patient (case 4) suffered from cardiac dysfunction due to right ventricular apical pacing (RVAP). Left bundle branch area pacing was successfully achieved in all patients with narrow QRS complexes and V1 lead showed changes like right bundle branch block in the pacing electrocardiogram. Left ventricular ejection fraction in case 4 recovered on the 3rd day after LBBAP. The median of left ventricular end diastolic diameter Z score of the 12 patients decreased from 1.75 to 1.05 3 months after implantation (p < 0.05). The median of paced QRS duration was 103 ms. The median of pacing threshold, R-wave amplitude and impedance were 0.85 V, 15 mV and 717 Ω respectively and remained stable during follow-up. No complications such as loss of capture, lead dislodgement or septal perforation occurred. Left bundle branch area pacing can be performed safely in children with narrow QRS duration and stable pacing parameters. Cardiac dysfunction caused by long-term RVAP can be corrected by LBBAP quickly.

Left Branch Cardiac Stimulation. Beginning of a Program in Icu

Cardiac pacing is the only treatment available for patients with Symptomatic bradyarrhythmias in the absence of reversible causes. For about 50 Apical right ventricular pacing has been used for years.

Initial Experience with Left Bundle Branch Area Pacing with Conventional Stylet-Driven Extendable Screw-In Leads and New Pre-Shaped Delivery Sheaths.

Until recently, left bundle branch area pacing (LBBAp) has mostly been performed using lumen-less fixed screw leads. There are limited data on LBBAp with conventional style-driven extendable screw-in (SDES) leads, particularly data performed by operators with no previous experience with LBBAp procedures. In total, 42 consecutive patients undergoing LBBAp using SDES leads and newly designed delivery sheaths (LBBAp group) were compared with those treated with conventional right ventricular pacing (RVp) for atrioventricular block (RVp group, n = 84) using propensity score matching (1:2 ratio). The LBBAp was successful in 83% (35/42) of patients, with satisfactory pacing thresholds (0.8 ± 0.2 V at 0.4 ms). In the LBBAp group, the mean paced-QRS duration obtained during RV apical pacing (173 ± 18 ms) was significantly reduced by LBBAp (116 ± 14 ms, p < 0.001). Compared with the RVp group, the LBBAp group showed more physiological pacing, suggested by a much narrower paced-QRS duration (116 ± 14 vs. 151 ± 21 ms, p < 0.001). The pacing threshold was comparable in both groups. The LBBAp group revealed stable pacing thresholds for 6.8 ± 4.8 months post-implant and no serious complications including lead dislodgement or septal perforation. The novel approach of LBBAp using SDES leads and the new dedicated pre-shaped delivery sheaths was effectively and safely performed, even by inexperienced operators with LBBAp procedures.

Left hemothorax resulting from delayed right ventricular apical pacing lead perforation without hemopericardium, a case report.

Introduction and importanceRight ventricular pacemaker lead perforation is a rare but well documented complication of pacemaker implantation. Lead perforation can cause an array of symptoms ranging from none to hemodynamic instability and tamponade. In previously reported cases, lead perforation has always been able to be confirmed by imaging, with computed tomography (CT) scan considered to be the gold standard diagnostic imaging modality.Case presentationAn 80-year-old male underwent uncomplicated implantation of a dual chamber pacemaker for sick sinus syndrome as an outpatient. Thirty-nine days later, the patient presented to the emergency department complaining of new-onset, left-sided, pleuritic chest pain. He was found to have unilateral hemothorax and abnormal pacemaker lead interrogation. Pacemaker lead perforation was suspected but not confirmed with imaging. Lead perforation was only identified after surgical exploration.Clinical discussionThis patient had multiple risk factors for pacemaker lead perforation. However, imaging, including CT scan was unable to confirm perforation. The presence of an otherwise unexplained left hemothorax strongly suggested that surgical intervention was indicated. The lead perforation was subsequently confirmed with subxiphoid exploration of the pericardial space. The mechanism of lead perforation resulting in hemothorax in this case is not straight forward, as no direct communication between the pericardial and pleural spaces was identified. However, previously described visceral pericardial self-sealing may contribute to the small pericardial accumulation described herein.ConclusionThis patient's presentation and clinical course underscore the importance of maintaining a high index of suspicion for pacemaker lead perforation despite a lack of confirmation with imaging.