Pacing Burden Research Articles

Left bundle branch area pacing in children – case series

Abstract Background Left bundle branch area pacing (LBBAP) is a new concept that provides physiological pacing with a narrow QRS duration. Recently published data suggest that LBBAP may prevent deleterious effects of right ventricular pacing, namely pacemaker-induced cardiomyopathy, especpecially in patients with expected high ventricular pacing burden, which may be of particular importance in children. Case summary Herein, we report successful implantation of Medtronic SelectSecure (Model 3830, Medtronic Inc.) right ventricle electrode in the region of left bundle branch area in three consecutive children (two 16-year-old and one 8-year-old). Indication for pacemaker implantation was third-degree atrioventricular block in all cases. Implantations were performed under general anaesthesia and there were no acute complications. During the median follow-up of six months, there were no adverse events and the electrical parameters of the device remained stable. Discussion Compared with adult patients, implantation of pacemakers in children may still be challenging, not only because of smaller body size but also due to continuing growth and a higher rate of lead and device-related complications. We have demonstrated that implantation of LBBAP in children is feasible and could be worth considering, particularly in patients with expected high ventricular pacing burden. Further studies are needed to assess the efficacy and safety of left bundle branch area pacing in children during long-term observation.

Lower Risk of New-Onset Atrial Fibrillation in Conduction System Pacing Compared With Right Ventricular Pacing.

Conduction system pacing (CSP) has been reported to improve clinical outcomes in comparison of right ventricular pacing (RVP). However, the performance between CSP and RVP on the risk of new-onset atrial fibrillation (AF) remains elusive. Four online databases were systematically searched up to July 1, 2024. Studies comprising the rate/risk of new-onset AF between CSP and RVP group were included. Subgroup analysis was performed to screen the potential determinants for the new-onset AF risk for CSP therapy. The pooled risk of new-onset AF based on ventricular pacing burden (Vp) between CSP and RVP group were evaluated. A total of six studies including 1577 patients requiring pacing therapy were eligible. The pooled new-onset AF rates for CSP and RVP group were 0.09 and 0.27, respectively. Compared with RVP group, CSP group showed a lower pooled risk (risk ratio [RR] 0.38, p = 0.000) and adjusted risk (hazard ratio [HR] 0.32, p = 0.000) of new-onset AF. Meanwhile, a significant intervention-covariate interaction for the adjusted risk of new-onset AF between CSP and RVP group was identified with Vp < 20% and Vp ≥ 20%. Our study suggests that CSP is associate with a significantly lower occurrence of new-onset AF compared with RVP. The Vp ≥ 20% may be the key determinant on the lower risk of new-onset AF with CSP therapy. https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023492551, identifier (CRD42023492551).

Predictive factors of high burden of ventricular pacing in patients undergoing permanent pacemaker implantation after transcatheter aortic valve implantation

Predictive factors of high burden of ventricular pacing in patients undergoing permanent pacemaker implantation after transcatheter aortic valve implantation

Mid-Term Impact of Conduction System Pacing on Overall Cardiac Performance: A Non-Randomized, Prospective, Single-Center Echocardiographic Study.

Introduction. Recently published data suggested significantly lower pacing-induced cardiomyopathy (PICM) incidence with conduction system pacing (CSP). Because most data evaluated only the impact on the left ventricle, this study aimed to assess changes in echocardiographic parameters of morphology and function for all heart chambers in patients with baseline preserved and mid-range LVEF over a medium-term follow-up period after CSP. Methods. A total of 128 consecutive patients with LVEF > 40% and successful CSP for bradyarrhythmic indication were prospectively enrolled. A complete 2D echocardiographic examination was performed at baseline and the last follow-up. Results. In total, 38 patients received His bundle pacing (HBP) and 90 received left bundle branch area pacing (LBBAP). The mean follow-up period was 699.2 ± 177.2 days, with 23 patients lost during this period. The ventricular pacing burden for the entire group was 97.2 ± 4.2%. Only three patients (2.9%) met the criteria for PICM. CSP led to a significant increase in LVEF (from 54.2 ± 7.9 to 56.7 ± 7.8%, p = 0.01) and a significant decrease in LV diastolic (from 107.2 ± 41.8 to 91.3 ± 41.8 mL, p < 0.001) and systolic (from 49.7 ± 21.4 to 39.5 ± 18.2 mL, p < 0.001) volumes. There were no significant changes in E/e', mitral regurgitation, atrial volumes, and right ventricle (RV) diameter. There was a significant improvement in RV function. Tricuspid regurgitation was the only parameter that worsened. There were no differences in evolution for each echocardiographic parameter between the HBP and the LBBAP groups. Conclusions. HBP and LBBAP are equally protective for harmful changes in both atria and ventricles. The prevalence of PICM, defined as a decrease in LVEF, is very low with CSP.

Upgrading Right Ventricular Pacing to Cardiac Resynchronization in HFrEF Patients Improves Symptoms and Functional Outcomes.

In the BUDAPEST (Biventricular Upgrade on left ventricular reverse remodeling and clinical outcomes in patients with left ventricular Dysfunction and intermittent or permanent APical/SepTal right ventricular pacing)-CRT Upgrade randomized trial, the authors have demonstrated improved mortality and morbidity after cardiac resynchronization therapy (CRT) upgrade in patients with heart failure with reduced ejection fraction (HFrEF) with high right ventricular (RV) pacing burden. This substudy sought to examine the impact of CRT upgrade on symptoms, functional outcome, and exercise capacity. In the BUDAPEST-CRT Upgrade trial, 360 HFrEF patients with pacemaker or implantable cardioverter-defibrillator (ICD) and≥20% RV pacing burden were randomly assigned (3:2) to cardiac resynchronization therapy with defibrillator (CRT-D) upgrade (n=215) or ICD (n=145). The prespecified tertiary endpoints were changes in quality of life (QoL) (EQ-5D-3L), NYHA functional class, 6-minute walk test, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels. Up to 12months, NYHA functional class improved in the CRT-D upgrade arm compared with ICD only (adjusted OR: 0.50 [95%CI: 0.32-0.80]; P = 0.003). A remarkable decrease was observed in NT-proBNP levels in the CRT-D arm (adjusted difference-1,257 pg/mL [95%CI:-2,287 to-228]; P = 0.017). The progression of age-related worsening of QoL was moderated by CRT-D upgrade (EQ-5D-3L difference by each year: 0.015 [95%CI: 0.005-0.025]; Pinteraction=0.003). However, exercise tolerance (6-minute walk test) remained unchanged in both groups. HFrEF patients with pacemaker/ICD and≥20% RV pacing burden receiving CRT upgrade showed a substantial improvement in NYHA functional class and decrease in natriuretic peptide levels, as compared with ICD alone. Moreover, CRT-D upgrade could moderate the progression of worsening of QoL attributed to ageing in this vulnerable, elderly patient population. (Biventricular Upgrade on left ventricular reverse remodeling and clinical outcomes in patients with left ventricular Dysfunction and intermittent or permanent APical/SepTal right ventricular pacing [BUDAPEST]-CRT Upgrade trial).

The usefulness of His bundle pacing in a heterogeneous population of patients with impaired left ventricular systolic function.

His bundle pacing (HBP) maintains a physiological activation pattern of ventricular activation, and in patients with intraventricular conduction delay (IVCD) it can normalize wide QRS duration. A total of 181 patients from the HBP registry were enrolled into a the study, which was conducted at the Department of Electrocardiology in Katowice, Poland. The patients had left ventricular ejection fraction (LVEF) < 50% and were implanted between November 2015 and April 2019. The HBP indications were as follows: 1) bradycardia and atrioventricular conduction disturbances with expected high pacing burden, 2) IVCD, LVEF ≤ 35%, with an indication for resynchronization therapy, 3) the need to upgrade to resynchronization therapy due to pacing-induced cardiomyopathy. Pacing parameters and echocardiographic and clinical data were assessed for up to 2 years of follow-up (FU). His bundle pacing was successful in 154 (85.1%) patients. Eighty-two patients completed a 6-month FU. The mean age was 70.6 ± 9.23 years, and 79% were males. At 6 months FU LVEF improved from 35.3 ± 8.22% to 43.1 ± 10.14% (p < 0.0001), and indexed left ventricular end-systolic volume (LVESVi) decreased from 63.1 ± 25.21 mL/m² to 51.9 ± 22.79 mL/m² (p < 0.0001). In 53.1%, the LVESVi reduction was greater than 15%. The improvement in LVEF and LVESVi was also observed after 24 months of FU. His bundle pacing in permanently paced patients when LVEF is reduced below 50% is associated with improvement in LVEF and reverse left ventricle remodeling.

Pacing dependency after TAVI, a lasting hazard in every case?

Abstract Introduction Atrioventricular (AV) conductions abnormalities that require permanent pacemaker (PPM) occur in up to 20% of patients after TAVI. The evolution of conduction abnormalities and the long-time pacing burden have not been fully characterized. We aim to characterize ventricular pacing burden after TAVI assessing also the impact of clinical and periprocedural factors. Methods Single centre retrospective registry including all consecutive patients undergoing TAVI between 01/2014 and 08/2021 that had a PPM implanted during index admission. Patients with in-hospital death were excluded. Baseline and pacing follow-up data were collected prospectively and assessed retrospectively using local electronic health records. We examined pacing burden as the percentage of ventricular pacing (VP%) and divided our cohort in 3 groups: i VP% ≤10%, ii 10% &amp;gt; VP% &amp;lt; 90%, iii VP% ≥90%. We assessed the difference between discharge and 1y VP% and the interaction between baseline characteristics. Results 766 patients underwent TAVI and 109 (14.2%) were included. The median age was 84 years (IQR 80 ; 90) and 44% were male (n = 48). 19 patients (17.4%) had previous 1st degree AV block (AVB) and 37 patients (33.9%) had previous right bundle branch block (RBBB). A self-expandable valve was implanted in 78 patients (71.6%). The median time between TAVI and PPM was 2 days (1;5). Sustained complete AVB (cAVB) occurred in 85 patients (78.0%) and was the most common indication for PPM. Data on VP% at discharge was available for 102 patients (93.5%). The median VP% at discharge was 100% (99 ; 100) with 4 patients (3.7%) having ≤10% VP% and 87 patients (79.8%) having ≥90% VP%. 95 patients (87.2%) completed the 1y follow-up. The VP% decreased significantly between discharge and 1y follow-up - 8.0 (IQR -59 ; 0 / p &amp;lt;0.05 Wilcoxon test) (Figure 1), similarly across valve type. At 1y follow-up, 20 patients (18.3%) had ≤10% VP% and 43 patients (39.4%) had ≥90% VP%. In the 18 patients (19.4%) without periprocedural sustained cAVB, 9 patients (50.0%) had ≤10% VP% and 1 patient (5.6%) had ≥90% VP%. In contrast, among patients with sustained cAVB, 11 patients (14.7%) had ≤10% VP% and 40 patients (53.3%) had ≥90% VP% (p &amp;lt;0.05 Chi-squared) (Figure 2). Conclusions In this study cohort the pacing burden significantly decreased in the 1st year after TAVI. It was significantly lower in patients without periprocedural sustained cAVB which suggests that a more conservative management may be considered in a small subgroup of patients.

Conduction system versus right ventricular pacing for atrioventricular block: a reconstructed individual participant data meta-analysis

Abstract Background Right ventricular pacing (RVP) is typically offered to patients with established or impending atrioventricular block (AVB) in the absence of left ventricular systolic dysfunction. Direct stimulation of His-Purkinje fibres via conduction system pacing (CSP) is an emerging alternative to RVP to prevent pacing-induced cardiomyopathy. Purpose To perform a systematic review and meta-analysis testing CSP versus RVP in patients with AVB and a left ventricular ejection fraction ≥35%. Methods Observational studies comparing CSP with RVP that reported clinical outcomes were systematically identified. The primary outcome was time-to-first all-cause mortality, heart failure hospitalisation (HFH) or upgrade to biventricular pacing. Secondary endpoints included the individual components of the primary endpoint. Individual participant time-to-event data (IPD) was obtained through data-sharing agreements or reconstructed from digitisation of Kaplan-Meier curves where available. Mixed-effects Cox proportional hazards regression that modelled between-study heterogeneity as a random intercept to account for differing baseline hazards between distinct study populations was performed on these data. Conventional pairwise random effects meta-analyses were also performed. This analysis was prospectively registered. Results 12 eligible studies enrolling 4627 patients were included. In reconstructed IPD pooled survival analyses, CSP associated with a 38% reduced hazard of the primary endpoint compared with RVP [hazard ratio 0.62, 95% CI 0.51 to 0.76, p&amp;lt;0.001] (Figure 1). In pairwise meta-analyses, CSP associated with a 46% risk reduction in the primary endpoint [relative risk (RR) 0.54, 95% CI 0.41 to 0.71, p&amp;lt;0.001] (Figure 2A). CSP also associated with reductions in risk of all-cause mortality [RR 0.60, 95% CI 0.45 to 0.80, p&amp;lt;0.001], HFH [RR 0.39, 95% CI 0.28 to 0.55, p&amp;lt;0.001] and upgrade to biventricular pacing [RR 0.19, 95% CI 0.07 to 0.52, p=0.001] compared with RVP (Figure 2B-D). Conclusions In reconstructed IPD pooled survival analyses, CSP associated with reductions in the primary composite endpoint of all-cause mortality, heart failure hospitalisation or upgrade to biventricular pacing compared with RVP, independent of ventricular pacing burden. This was mirrored in conventional meta-analyses of the primary composite endpoint, and when individual components of the composite were analysed. It may not be necessary to predict which patients will have an elevated pacing burden when applying this therapy. Until randomised data from the PROTECT-HF trial becomes available, this analysis offers the most precise summary estimate of the comparative effects of CSP versus RVP in patients with an AVB indication for pacing, but no evidence of heart failure.Kaplan-Meier plot comparing CSP vs RVPForest plots for major endpoints

Routine chest X-ray post cardiac implantable electronic device implantation: is it really required? Experience from a tertiary centre

Abstract Introduction The 2021 EHRA expert consensus statement on pacemaker (PPM) and transvenous implantable cardioverter defibrillator (ICD) implant technique proposes a chest X-ray (CXR) prior to hospital discharge in all patients. This recommendation serves the dual purpose of excluding pneumothorax following subclavian or axillary access (SAA) and documenting lead position. Purpose Given that cephalic venous access (CA) precludes pneumothorax, the utility of CXR as a tool for identifying early lead displacement (LD) in these patients warrants further examination. We studied the yield of post implant CXR, device interrogation (DI), or both for the identification of pneumothorax and LD in patients undergoing transvenous PPM or ICD implant via SAA or CA. Methods 4,051 consecutive PPM or ICD devices were implanted at a tertiary centre between 2016-2019. Lead position was documented fluoroscopically on conclusion of all procedures. A subsequent post implant CXR was performed in cases of SAA, plus in those CA patients requiring imaging for another indication (e.g. pulmonary oedema). Post implant DI was only performed in patients with a high anticipated burden of ventricular pacing (e.g. high-grade atrioventricular block). All patients underwent clinical review with repeat DI at 30 days post implant. LD was defined as a clinically significant translocation of a lead requiring repositioning or reprogramming. Results For the whole cohort, the incidence of LD at 30 days was 2.2% (n=89), and the incidence of pneumothorax (within the SAA group) was 0.9% (n=11). The venous access method used, post implant investigations, and the incidence of LD is shown in Figure 1. 1,282 patients (31.6%) required SAA; CXR was performed in all, and 9 LDs were identified (0.7%). However, four patients (0.3%) with ‘normal’ CXRs had evidence of LD on inpatient DI, and a further 17 LDs (1.3%) were confirmed on the 30 day DI despite a ‘normal’ CXR. 2,769 patients (68.4%) underwent CA; 309 (11%) required CXR. This identified LD in four patients (1.3%), with three further patients (1%) found to have LD on subsequent inpatient DI despite a ‘normal’ CXR. A further four LDs (1.3%) were diagnosed at 30 day DI. The majority (89%, n=2,460) of CA patients were discharged without CXR. 30% (n=825) of these patients required inpatient DI; this identified 13 LDs (1.6%). Accordingly, 59% (n=1,635) of CA patients had no post procedural investigations; 24 (1.5%) were found to have LD at 30 day DI. Conclusions In patients who developed LD within 30 days of a PPM or ICD implant, a post implant CXR identified this in only 32% of cases (n=13/41), and the overall sensitivity of CXR for LD was low (50%). Additionally, the majority of LDs (54%) occurred after hospital discharge. We suggest that the utility of post implant CXR for identifying LD is limited, and that CXR should not be considered an essential investigation in CA device implants.Figure 1

Mechanical dyssynchrony and response to cardiac resynchronization therapy in heart failure patients with right ventricular pacing: a pre-specified subgroup analysis of the BUDAPEST CRT Upgrade trial

Abstract Introduction The BUDAPEST CRT Upgrade trial has established the strong clinical benefit of upgrading heart failure patients with a reduced left ventricular (LV) ejection fraction (HFrEF) and a high right ventricular pacing (RVP) burden to cardiac resynchronization therapy with defibrillator (CRT-D). Importantly, however, the CRT upgrade response is not homogeneous regarding LV reverse remodeling and associated clinical outcomes. The presence of mechanical dyssynchrony (MD) assessed by echocardiography has been linked to more CRT benefits; still, its change in response to CRT and added prognostic value in HFrEF patients with high RVP are scarcely investigated. Purpose Accordingly, we aimed to assess the prevalence, clinical characteristics, CRT response rate, and prognostic value of RVP-induced MD in the BUDAPEST CRT Upgrade cohort. Methods The multicentre, randomized, controlled trial enrolled 360 HFrEF patients with a pacemaker or implantable cardioverter defibrillator (ICD) and significant RVP (≥ 20%) who were randomly assigned to receive CRT-D upgrade or ICD in a 3:2 ratio. Protocol echocardiography was performed at baseline and at 12-month follow-up visits and was evaluated at a central core lab. Beyond LV end-diastolic (EDV) and end-systolic volumes (ESV), longitudinal strain-derived septal deformation patterns by speckle tracking were assessed to determine the presence of RVP-induced MD. The endpoints were volumetric non-response (defined by a relative decrease in LV ESV &amp;lt;15%) and the composite of volumetric non-response or HF hospitalization. Results The echocardiographic assessment was feasible in 325 patients at baseline; 133 (41%) patients presented with MD. Females were more likely to present with MD (female vs. male, 65% vs. 38%, p=0.003). MD patients had higher LV EDV (MD vs. no-MD, 248±78 vs. 219±78 mL, p=0.001) and LV ESV (190±67 vs. 165±64 mL, p&amp;lt;0.001) at baseline. In the CRT-D group, 126 (75%) patients were volumetric responders, and 41 (25%) were non-responders at 12 months. CRT patients with baseline MD were less likely to experience volumetric non-response (OR 0.35 [95% CI 0.15-0.82], p=0.015) or the composite endpoint (OR 0.37 [95% CI 0.17-0.77], p=0.008). Out of 57 CRT patients with baseline MD who had follow-up assessment available, 52 (91%) patients had a favorable change: the MD pattern disappeared. Patients with MD resolution at 12 months were less likely to experience volumetric non-response or the composite endpoint (OR 0.39 [95% CI 0.17-0.93], p=0.034; OR 0.38 [95% CI 0.16-0.86], p=0.021, respectively). CRT patients with resolved MD were less likely of ischemic etiology and had 100% posterior or lateral LV lead location. Conclusions The presence of RVP-induced MD and its resolution is associated with better clinical response in HFrEF patients undergoing CRT-D upgrade. MD assessment can refine patient selection algorithms of CRT.Figure 1

Correlation of prosthesis position on mid-term pacing burden in patients with new permanent pacemaker after TAVI

Abstract Background Prior studies suggest a strong correlation of the final prosthesis position on the occurrence of new conduction disturbances resulting in permanent pacemaker (PPM) implantation after transcatheter aortic valve implantation (TAVI). A high burden right ventricular pacing (PPM stimulation rate of &amp;gt; 20 %) is associated with poor long-term outcomes. So far, data about predictors influencing the PPM stimulation rate after TAVI are scarce. Purpose Thus, the purpose of this study was to evaluate the influence of the three-dimensional transcatheter heart valve (THV) position, as well as device landing zone characteristics or peri-/post-procedural factors on the stimulation rate in patients with new implanted PPM as TAVI complication. Materials: We evaluated the final THV position of 387 patients (106 with self-expanding Evolut R THV, 281 with balloon-expandable Sapien 3 THV) using fusion imaging of pre- and post-TAVI computed tomography angiography (CTA) to obtain a three-dimensional reconstruction of the THV within the native annulus region. The length of the THV above and below the native annulus was measured within the fused images to assess the implantation depth. PPM stimulation rates were examined pre-discharge and after 3 months. Patient’s clinical long-term outcome was evaluated over 5 years via standardized questionnaire as well as contacting general practitioners. Results Out of the 387 patients 112 (29%) received a new PPM pre-discharge after TAVI between 2014 and 2022. They were grouped into patients with stimulations rate below and above 20%. A stimulation rate &amp;gt; 20% in the PPM control before discharge and after three months was detected in 69 % and 67 % of them, respectively. Using uni- and multivariate logistic regression analysis, only new occurred third degree atrioventricular blocks (p=0.007) was identified as predictor for high burden right ventricular pacing after PPM-implantation as well as after 3 months. The implantation depth of the THV showed no influence on the PPM stimulation rate – neither the mean value nor the exact implantation depth adjacent the left, right and non-coronary cusp (P=0.455, P=0.108 and P=0.932, respectively). There were no significant differences regarding MACE between both groups during long-term follow-up; only the degree of dyspnea 5 years after TAVI was significantly higher in patients with a stimulation rate &amp;gt; 20% (p=0.01). Conclusion We detected no correlation of the exact three-dimensional THV position on mid-term pacing burden in 112 patients implanted with a new PPM after TAVI using CTA fusion imaging. Only a new occurred third degree atrioventricular block was a predictor for a high burden right ventricular pacing (stimulation rate &amp;gt;20%). These results provide important insights into which patients actually require PPM implantation after TAVI.

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.

Comparison of clinical and echocardiographic outcomes between left bundle branch area pacing and right ventricular pacing in older patients.

Left bundle branch area pacing (LBBAP) is safe and effective, but studies in older patients are lacking. This study compared the clinical and echocardiographic outcomes of LBBAP and right ventricular pacing (RVP) in patients aged ≥75 years. This prospective observational study included older patients with symptomatic bradycardia who underwent LBBAP or RVP between 2019 and 2022. Clinical data, including pacing and electrophysiological characteristics, echocardiographic measurements, and device-related complications were collected. The primary endpoint was a composite of all-cause mortality, heart failure hospitalization, and upgrade to biventricular pacing. Secondary outcomes included changes in left ventricular ejection fraction (LVEF). Of 267 included patients, 110 underwent LBBAP and 157 underwent RVP. LBBAP was successful in 109 patients (success rate: 99.1%), with one patient eventually undergoing RVP. The pacing parameters of LBBAP were similar to those of RVP, except for a significantly narrower paced QRS duration (112.8±11.6vs. 138.3±23.9ms, p<.001). Ventricular lead implanting procedural duration was longer for LBBAP than RVP (14.0vs. 6.0min, p<.001), as was the fluoroscopy time (4.0vs. 2.0min, p<.001). During a mean follow-up period of 31.0±16.8 months, the primary outcome incidence was significantly lower following LBBAP than RVP (15.1%vs. 21.1%; hazard ratio, 0.471; 95% confidence interval, 0.215-1.032; p=.036) in 149 patients (55.8%) with ventricular pacing burden>20%. RVP reduced LVEF from 62.7±4.1% at baseline to 59.8±7.8% at the final follow-up (p=.001), whereas LBBAP preserved LVEF (61.4±6.3%vs. 60.1±7.4%, p=.429). LBBAP demonstrated improved clinical outcomes compared with RVP and maintained LVEF in older patients with high ventricular pacing burdens.

Chronic Right Ventricular Pacing Post-Transcatheter Aortic Valve Replacement Attenuates the Benefit on Left Ventricular Function.

Background: Conduction abnormality post-transcatheter aortic valve implantation (TAVI) remains clinically significant and usually requires chronic pacing. The effect of right ventricular (RV) pacing post-TAVI on clinical outcomes warrants further studies. Methods: We identified 147 consecutive patients who required chronic RV pacing after a successful TAVI procedure and propensity-matched these patients according to the Society of Thoracic Surgeons (STS) risk score to a control group of patients that did not require RV pacing post-TAVI. We evaluated routine echocardiographic measurements and performed offline speckle-tracking strain analysis for the purpose of this study on transthoracic echocardiographic (TTE) images performed at 9 to 18 months post-TAVI. Results: The final study population comprised 294 patients (pacing group n = 147 and non-pacing group n = 147), with a mean age of 81 ± 7 years, 59% male; median follow-up was 354 days. There were more baseline conduction abnormalities in the pacing group compared to the non-pacing group (56.5% vs. 41.5%. p = 0.01). Eighty-eight patients (61.6%) in the pacing group required RV pacing due to atrioventricular (AV) conduction block post-TAVI. The mean RV pacing burden was 44% in the pacing group. Left ventricular ejection fraction (LVEF) was similar at follow-up in the pacing vs. non-pacing groups (57 ± 13.0%, 59 ± 11% p = 0.31); however, LV global longitudinal strain (-12.7 ± 3.5% vs. -18.8 ± 2.7%, p < 0.0001), LV apical strain (-12.9 ± 5.5% vs. 23.2 ± 9.2%, p < 0.0001), and mid-LV strain (-12.7 ± 4.6% vs. -18.7 ± 3.4%, p < 0.0001) were significantly worse in the pacing vs. non-pacing groups. Conclusions: Chronic RV pacing after the TAVI procedure is associated with subclinical LV systolic dysfunction within 1.5 years of follow-up.

Mid-term clinical outcomes of left bundle branch area pacing compared to accurate right ventricular septal pacing.

Although left bundle branch area pacing (LBBAP) reportedly results in fewer adverse outcomes after implantation than conventional stylet-guided right ventricular septal pacing (RVSP), previous studies have not compared LBBAP with accurate RVSP using a delivery catheter. The aim of this study was to compare clinical outcomes between LBBAP and accurate RVSP among patients with atrioventricular block (AVB). This single-center observational study enrolled 160 patients requiring RV pacing due to symptomatic AVB between September 2018 and December 2021. Primary composite outcomes included all-cause death, hospitalization due to heart failure (HF), and upgrading to biventricular pacing. Secondary composite outcomes included any procedural and postprocedural complications. Overall, 160 patients were analyzed (LBBAP, n = 81; RVSP, n = 79). No significant differences in baseline characteristics were observed between the two groups. The RV pacing burden at 1year after implantation was 90.8% ± 20.4% and 86.2% ± 22.6%, respectively (p = 0.21). During a mean follow-up of 840 ± 369days, the incidence of the primary outcome was significantly lower with LBBAP (4.9%) compared to RVSP (22.8%) (Log-rank p = 0.02). There was no significant difference in the incidence of the secondary outcome between the two groups (3.7% vs. 5.1%, p = 0.65). In the multivariate analysis, baseline QRS duration, RV pacing burden, and LBBAP were independently associated with the primary outcome (baseline QRS duration: hazard ratio [HR], 1.01; 95% confidence interval [CI], 1.00-1.02; p < 0.001; RV pacing burden: HR, 1.01; 95% CI, 1.00-1.02; p < 0.001; LBBAP: HR, 0.45; 95% CI, 0.31-0.64; p < 0.001). In patients requiring frequent RV pacing, LBBAP was associated with reduced adverse clinical outcome compared to accurate RVSP using a delivery catheter.

Benefits of upgrading right ventricular to biventricular pacing in heart failure patients with atrial fibrillation.

Recommendations on cardiac resynchronization therapy (CRT) in patients with atrial fibrillation or flutter (AF) are based on less robust evidence than those in sinus rhythm (SR). We aimed to assess the efficacy of CRT upgrade in the BUDAPEST-CRT Upgrade trial population by their baseline rhythm. Heart failure patients with reduced ejection fraction (HFrEF) and previously implanted pacemaker (PM) or implantable cardioverter defibrillator (ICD) and ≥20% right ventricular (RV) pacing burden were randomized to CRT with defibrillator (CRT-D) upgrade (n = 215) or ICD (n = 145). Primary [HF hospitalization (HFH), all-cause mortality, or <15% reduction of left ventricular end-systolic volume] and secondary outcomes were investigated. At enrolment, 131 (36%) patients had AF, who had an increased risk for HFH as compared with those with SR [adjusted hazard ratio (aHR) 2.99; 95% confidence interval (CI) 1.26-7.13; P = 0.013]. The effect of CRT-D upgrade was similar in patients with AF as in those with SR [AF adjusted odds ratio (aOR) 0.06; 95% CI 0.02-0.17; P < 0.001; SR aOR 0.13; 95% CI 0.07-0.27; P < 0.001; interaction P = 0.29] during the mean follow-up time of 12.4 months. Also, it decreased the risk of HFH or all-cause mortality (aHR 0.33; 95% CI 0.16-0.70; P = 0.003; interaction P = 0.17) and improved the echocardiographic response (left ventricular end-diastolic volume difference -49.21 mL; 95% CI -69.10 to -29.32; P < 0.001; interaction P = 0.21). In HFrEF patients with AF and PM/ICD with high RV pacing burden, CRT-D upgrade decreased the risk of HFH and improved reverse remodelling when compared with ICD, similar to that seen in patients in SR.

Outcomes with physiologic His bundle pacing in patients with narrow QRS complex

BackgroundIn patients with narrow QRS complex, both ventricular and biventricular pacing is associated with increased cardiac morbidity and mortality. This risk is not decreased by ventricular pacing avoidance algorithms, which cause nonphysiologic atrioventricular (AV) delays. ObjectiveThis study aimed to report outcomes in patients with narrow QRS complex when the paced complex is in normal range and physiologic AV delays are programmed. MethodsIn 196 patients with QRS duration of 92 ± 10 ms, permanent pacing was done at the site of the His bundle electrogram. The pacemakers were then programmed to maintain physiologic AV delays and to increase heart rates in response to exercise. Patients received usual care and were observed for 3 years. ResultsThe paced complex exhibited a delta wave, and the ventricular activation time, QRS axis, and lead I voltage remained in normal range. Physiologic programming resulted in His bundle pacing burden of 92%. In patients with decreased ejection fraction, there was significant improvement in left ventricular function, left ventricular dilation, and mitral regurgitation (P < .003). In patients with normal ejection fraction, left ventricular function remained normal without new valvular abnormalities. The 3-year all-cause mortality was 10%, and there was no increase in heart failure admissions. ConclusionIn patients with narrow QRS complex, when paced QRS morphology is maintained in normal range and AV dyssynchrony is avoided, His bundle pacing is associated with low all-cause mortality and improvement in abnormal echocardiographic parameters. The paced QRS morphology and physiologic AV delays may be important factors to evaluate in future trials of conduction system pacing.

Atrioventricular Interval Modulation (AVIM) therapy for ambulatory systolic blood pressure (aSBP) reduction with a dual chamber pacemaker: comparison of conduction system vs. right ventricular pacing

Abstract Background AVIM is a pacing algorithm incorporated into dual-chamber pacemakers to treat hypertension. AVIM delivers repeating sequences of short and longer atrioventricular delays leading to reduced preload and afterload. The therapy lowers blood pressure while simultaneously modulating the autonomic nervous system. The marked blood pressure reducing capability of AVIM has been already confirmed by a previous randomized clinical trial using conventional right ventricular (RV) pacing. Nevertheless, whether a similar blood pressure reduction could be also achieved by AVIM when conduction system pacing (CSP) is applied instead of RV pacing has not been investigated yet. Considering the facts that CSP using Left Bundle Branch Area Pacing (LBBAP) has been found to elicit more synchronous ventricular contraction and improved hemodynamics compared to RV pacing and AVIM is associated with a signficant burden of ventricular pacing, it is tempting to hypothesize that AVIM with CSP could be particularly beneficial. Purpose To compare the effects of AVIM therapy when delivered via an LBBAP location with the effects when delivered using a traditional RV lead location. Methods This single-center study evaluated subjects indicated for a dual chamber pacemaker who also had uncontrolled hypertension despite a stable dose of ³ 1 antihypertensive drug. Leads were placed in the RV or the LBBAP position. Subjects entered a run-in period of 4 weeks in which baseline office (oSBP)and 24-hour aSBP were measured. Subjects with baseline aSBP &amp;gt;130 mmHg and oSBP&amp;gt;140 mmHg at week 4 were included in the study. AVIM therapy was activated and a 24-hour aSBP was performed immediately after activation. Results Using a dedicated CSP pacemaker lab setup, CSP was performed in 5 patients with the Select Secure electrode (model 3830-69 cm) delivered via a fixed curve sheath (C315HIS). During the run in phase, in 3 out of the 5 CSP-AVIM patients, high blood pressure did not reach the level of inclusion and therefore these patients were not used for further analysis. In the remaining two patients, AVIM was activated. These two patients had a V6 stimulus-peak time of 69 ms and 61 ms, while V1 stimulus peak time was: 121ms and 109ms respectively. The effect of AVIM on 24-hour aSBP in the activated CSP-AVIM patients was compared to the average effect seen in patients from the same center enrolled in the prior randomized study with leads in the RV. Table 1 shows individual aSBP values for the two patient groups. Results suggest that delivery of AVIM therapy through leads in either position generates a significant reduction in blood pressure: -24.1 mmHg vs. -15.4 mmHg when the lead is placed in LBBAP or RV positions respectively. Conclusion These results demonstrate a significant reduction in aSBP in both lead locations. Additional studies evaluating larger sample sizes are required to assess if specific lead positions are preferable.Table 1

The effect of cardiac resynchronisation therapy upgrade from right ventricular pacing on symptoms and functional clinical outcomes, results from the BUDAPEST-CRT Upgrade trial

Abstract Background Based on the results of the BUDAPEST-CRT Upgrade trial, in patients with intermittent or permanent right ventricular (RV) pacing and reduced left ventricular ejection fraction (HFrEF) upgrade to cardiac resynchronization therapy (CRT) reduces morbidity and mortality. Purpose Whether the substantial treatment effect of the CRT upgrade could also be detected in a better functional and exercise capacity is scarcely investigated. We examined the changes of the prespecified tertiary endpoints such as symptoms, quality of life (QoL), exercise capacity and natriuretic peptide measurement from baseline to 12 months. Methods In the BUDAPEST CRT Upgrade trial 360 HFrEF patients with a priorly implanted PM or ICD and &amp;gt;20% of RV pacing burden were randomly assigned to CRT-D upgrade (n=215) or ICD (n=145) in a 3:2 ratio. The prespecified tertiary endpoints were changes in quality of life measured by EQ-5D-3L, New York Heart Association (NYHA) functional class, 6-minute walk test (6-MWT), and NT-proBNP. When data of trial patients were unavailable due to death at 12 months, imputed values were used as 0 (6MWT) and 0 score (EQ-5D-3L) or a 5th grade (NYHA class). Responders were defined as &amp;gt;15% change of left ventricular end-systolic volume at 12 months. Results From baseline to 12 months, NYHA functional class improved in the CRT-D upgrade arm compared with the ICD only group [adjusted odds ratio (OR) 0.50; 95% CI 0.32-0.80; P=0.003]. According to the adjusted model there was a statistically significant decrease in the NT-proBNP [adjusted difference -1257 pg/mL; 95% CI -2287 – (-228); P=0.017]. In responders, the changes in NT-proBNP levels were significantly greater than in non-responders [adjusted difference -1635 pg/mL; 95% CI -2811 - (-459); P=0.007]. The progression of worsening of QoL attributed to ageing was moderated only by CRT-D upgrade [EQ-5D-3L difference by age -0.01; 95% CI -0.02 - (-0.003); P=0.004; interaction P=0.003]. 6MWT did not improve significantly in either group. Conclusions Patients receiving CRT upgrade showed a substantial improvement in symptoms and a significant decrease in natriuretic peptide levels, as compared to ICD alone, which was more pronounced in responders. Moreover, CRT-D upgrade could moderate the progression of worsening of quality of life attributed to ageing in this vulnerable, older patient population.

Comparing Left Bundle Branch Area vs Right-Ventricular Septal Pacing in High-Degree Conduction Disease After Transcatheter Aortic Valve Replacement: Randomized Trial Study Protocol

Left bundle branch area pacing (LBBAP) is a novel method of conduction-system pacing in the muscular interventricular septum. Although LBBAP has been shown to produce physiologic electrical and mechanical intraventricular synchrony, superiority of LBBAP, compared to right ventricular septal pacing (RVSP) at preserving normal left-ventricular (LV) systolic function after transcatheter aortic valve replacement (TAVR) has not been demonstrated. Left Bundle BRAVE is an investigator-initiated, multicentre, prospective, double-blinded, randomized, crossover study investigating the superiority of LBBAP, compared to RVSP, with respect to preservation of systolic function in patients with high-degree conduction disease after TAVR. Adults with severe aortic stenosis and normal systolic function who sustain high-grade atrioventricular block within 4 weeks of TAVR are eligible. All subjects receive a biventricular pacemaker generator with RVSP, and LBBAP leads. Participants are randomly assigned to 9 months of each pacing mode, in series. The primary endpoint is change in global longitudinal strain, tested in series with change in LV ejection fraction, comparing RVSP to LBBAP. Secondary endpoints include the following: echocardiographic markers of interventricular synchrony and right ventricular performance; heart failure functional status and symptom classification; 6-minute walk test results; pacemaker and lead performance; and brain natriuretic peptide concentration. The Left Bundle BRAVE study is designed to identify an upstream and clinically relevant marker of superiority in LBBAP, compared to RVSP, at preventing deterioration of LV function in patients with a high ventricular pacing burden after TAVR. ClinicalTrials.gov identifierNCT05541679