Comparison of clinical outcomes between transthoracic echocardiography- and X-ray-guided left bundle branch pacing for bradycardia: A randomized controlled trial.

INTRODUCTION:Left bundle branch pacing (LBBP) is a physiological pacing modality. However, the long procedure and fluoroscopy time of LBBP is still a problem. This study aims to compare the clinical outcomes between transthoracic echocardiography (TTE)- and X-ray-guided LBBP.METHODS:This is a single-center, prospective, randomized controlled study. Consecutive patients who underwent LBBP in our team from June 2022 to November 2022 were enrolled. Procedure and fluoroscopy time, pacing parameters, electrophysiological and echocardiographic characteristics, as well as complications were recorded at implantation and during follow-up.RESULTS:In this study, 60 patients were enrolled and divided into two groups: 30 patients were allocated to the X-ray group and the remaining 30 to the TTE group. There was no significant difference in the success rate between the two groups (86.7% vs. 76.7%, p = .317). The procedure time of TTE group was comparable to that of the X-ray group (9.0 vs. 12.0 min, p = .063). However, the fluoroscopy time in the TTE group was significantly lower than that of the X-ray group (2.5 vs. 5.0 min, p = .002). There were no statistically significant differences in pacing parameters, electrophysiological and echocardiographic characteristics, or complications between the two groups at implantation and during follow-up.CONCLUSION:TTE-guided LBBP is a feasible and safe method. Compared with X-ray, TTE showed a comparable success rate and procedure time, but it could significantly reduce the fluoroscopy time of LBBP.

New-onset atrial fibrillation following left bundle branch area pacing vs. right ventricular pacing: a two-centre prospective cohort study.

AIMS:To investigate whether left bundle branch area pacing (LBBAP) can reduce the risk of new-onset atrial fibrillation (AF) compared with right ventricular pacing (RVP).METHODS AND RESULTS:Patients with indications for dual-chamber pacemaker implant and no history of AF were prospectively enrolled if they underwent successful LBBAP or RVP. The primary endpoint was time to the first occurrence of AF detected by pacemaker programming or surface electrocardiogram. Follow-up at clinic visit was performed and multivariate Cox regression models were applied to evaluate the effect of LBBAP on new-onset AF. The final analysis included 527 patients (mean age 65.3 ± 12.6, male 47.3%), with 257 in the LBBAP and 270 in the RVP groups. During a mean follow-up of 11.1 months, LBBAP resulted in significantly lower incidence of new-onset AF (7.4 vs. 17.0%, P < 0.001) and AF burden (3.7 ± 1.9 vs. 9.3 ± 2.2%, P < 0.001) than RVP. After adjusting for confounding factors, LBBAP demonstrated a lower hazard ratio for new-onset AF compared with RVP {hazard ratio (HR) [95% confidence interval (CI)]: 0.278 (0.156, 0.496), P < 0.001}. A significant interaction existed between pacing modalities and the percentage of ventricular pacing (VP%) (P for interaction = 0.020). In patients with VP ≥ 20%, LBBAP was associated with decreased risk of new-onset AF compared with RVP [HR (95% CI): 0.199 (0.105, 0.378), P < 0.001]. The effect of pacing modalities was not pronounced in patients with VP < 20% [HR (95% CI): 0.751 (0.309, 1.823), P = 0.316].CONCLUSION:Left bundle branch area pacing demonstrated a reduced risk of new-onset AF compared with RVP. Patients with a high ventricular pacing burden might benefit from LBBAP.

Tricuspid regurgitation following pacemaker implantation for bradycardia: a two-year study comparing different pacing strategies.

Early left bundle branch pacing in heart failure with mildly reduced ejection fraction and left bundle branch block.

BACKGROUND:Left bundle branch pacing (LBBP) achieves resynchrony and improves cardiac function in heart failure (HF) patients with reduced ejection fraction (EF) by correcting left bundle branch block (LBBB). Few data on the efficacy of early LBBP in HF with mildly reduced EF (HFmrEF) and LBBB have been reported.OBJECTIVE:The purpose of this study was to explore the efficacy of early LBBP in patients with HFmrEF and LBBB.METHODS:Consecutive patients with HFmrEF (left ventricular EF [LVEF] 35%-50%) and LBBB were prospectively enrolled to receive LBBP (Early-LBBP group) plus guideline-directed medical therapy (GDMT) or GDMT alone (GDMT group). Study outcomes included changes in LVEF, LV end-diastolic diameter (LVEDD), New York Heart Association (NYHA) functional classification, and N-terminal pro-brain natriuretic peptide (NT-proBNP), and clinical events (HF rehospitalization or syncope). Subgroup analysis compared efficacy of LBBP between patients with LBBB only without comorbidities or late gadolinium enhancement (LGE) (LBBB-Only group) and patients with either comorbidities or LGE (LBBB-Combined group).RESULTS:Fifty-four patients were enrolled and analyzed (37 Early-LBBP group; 15 GDMT group). LBBP achieved greater improvement in LVEF (+14.75% ± 7.37% vs -2.42% ± 2.84%; P <.001), reduction of LVEDD (-7.51 ± 5.40 mm vs -0.87 ± 4.36 mm; P <.001) and NYHA classification (-0.84 ± 0.76 vs -0.13 ± 0.74; P = .004), and similar reduction of NT-proBNP (-408.83 ± 920.29 pg/mL vs -229.05 ± 1579.17 pg/mL; P = .610) at 6 months. Early LBBP showed significantly reduced clinical events (0.0% vs 40.0%; P <.001) after 20.68 ± 13.55 months of follow-up. Subgroup analysis showed patients in the LBBB-Only group benefited more from LBBP with regard to LVEF improvement and LVEDD reduction than the LBBB-Combined group.CONCLUSION:Early LBBP with GDMT demonstrated greater improvement of cardiac function and reduced clinical events than GDMT alone in patients with HFmrEF and LBBB.

The initial experience of left bundle branch area pacing in patients with hypertrophic cardiomyopathy.

PURPOSE:Whether left bundle branch area pacing (LBBAP) could be achieved in patients with hypertrophic cardiomyopathy (HCM) requiring ventricular pacing remains unknown. The present study aimed to investigate the feasibility and effect of LBBAP in HCM.METHODS:Patients with HCM who underwent LBBAP were recruited from November 2018 to September 2021. Clinical characteristics, echocardiographic, and pacing parameters were prospectively collected at baseline and during follow-up.RESULTS:Eleven consecutive HCM patients who attempted LBBAP were included (mean age 64.0 ± 8.7 years, female 45.5%, mean interventricular septum 16.7 mm). The success rate of LBBAP was 36.4% (4/11) and the reason for failed LBBAP in other seven HCM patients was the inability to screw the lead into the deep septum or capture the left bundle branch. Patients with successful LBBAP had significantly narrower QRS duration than those with failed cases (118.0 ± 3.7 ms vs. 140.9 ± 9.4 ms, p = .01) while the capture thresholds, sensing amplitudes, and pacing impedances were similar. Successful cases presented with less positive late gadolinium enhancement (25.0% vs. 71.4%, p = .02) and thinner interventricular septum thickness (14.5 ± 1.0 mm vs. 18.0 ± 2.5 mm, p = .02) compared with failed cases. Pacing parameters remained stable and no procedure-related complications occurred during a mean follow-up of 8.9 ± 7.3 months.CONCLUSION:LBBAP may be successfully achieved in less than half of HCM patients due to thick interventricular septum and heavy burden of myocardial fibrosis. Pacing strategies should be cautiously considered in patients with HCM.

Tricuspid regurgitation outcomes in left bundle branch area pacing and comparison with right ventricular septal pacing.

Randomized Trial of Left Bundle Branch vs Biventricular Pacing for Cardiac Resynchronization Therapy.

BACKGROUND:Left bundle branch pacing (LBBP) is the most rapidly growing conduction system pacing technique that is capable of correcting intrinsic left bundle branch block (LBBB). As such, it is potentially an optimal alternative to cardiac resynchronization therapy (CRT) with biventricular pacing (BiVP).OBJECTIVES:The authors sought to compare the efficacy of LBBP-CRT with BiVP-CRT in patients with heart failure and reduced left ventricular ejection fraction (LVEF).METHODS:This is a prospective, randomized trial of patients with nonischemic cardiomyopathy and LBBB with 6-month preplanned follow-up. Crossovers were allowed if LBBP or BiVP were unsuccessful. The primary endpoint was the difference in LVEF improvement between 2 groups. The secondary endpoints included changes in echocardiographic measurements, N-terminal pro-B-type natriuretic peptide (NT-proBNP), New York Heart Association functional class, 6-minute walk distance, QRS duration, and CRT response.RESULTS:The study included 40 consecutive patients (20 males, mean age 63.7 years, LVEF 29.7% ± 5.6%). Crossovers occurred in 10% of LBBP-CRT and 20% of BiVP-CRT. All patients completed follow-up. Intention-to-treat analysis showed significantly higher LVEF improvement at 6 months after LBBP-CRT than BiVP-CRT (mean difference: 5.6%; 95% CI: 0.3-10.9; P = 0.039). LBBP-CRT also appeared to have greater reductions in left ventricular end-systolic volume (-24.97 mL; 95% CI: -49.58 to -0.36 mL) and NT-proBNP (-1,071.80 pg/mL; 95% CI: -2,099.40 to -44.20 pg/mL), and comparable changes in New York Heart Association functional class, 6-minute walk distance, QRS duration, and rates of CRT response compared with BiVP-CRT.CONCLUSIONS:LBBP-CRT demonstrated greater LVEF improvement than BiVP-CRT in heart failure patients with nonischemic cardiomyopathy and LBBB. (Left Bundle Branch Pacing Versus Biventricular Pacing for Cardiac Resynchronization Therapy [LBBP-RESYNC]; NCT04110431).

The mediation function of resting heart rate in how physical activity improves all-cause mortality: Continuous and automatic measurement via cardiac implantable electronic devices.

Background:Physical activity (PA) and resting heart rate (RHR) are connected with all-cause mortality. Moreover, there was an inverse correlation between PA and RHR. However, the causal relationship between PA, RHR, and long-term mortality has been rarely evaluated and quantified, particularly the mediation effect of RHR in the association between PA and all-cause mortality.Objective:To describe the relationship between PA and RHR when consistently measured via cardiac implantable electronic devices (CIED) and further explore the mediation effect of PA on all-cause mortality through RHR.Materials and methods:Patients who underwent CIED implantation and received remote home monitoring services were included. During the first 30-60 days after CIED implantation, daily PA and RHR were continuously measured and automatically transmitted by CIED. The primary endpoint was all-cause mortality. The multiple linear regression model was used to confirm the relationship between PA and RHR. The predictive values of both PA and RHR for all-cause mortality were assessed by multivariable Cox proportional hazards models. The causal mediation model was further established to verify and quantify the mediation effect of RHR in the association between PA and all-cause mortality.Results:A total of 730 patients with CIED were included. The mean daily PA and RHR were 10.7 ± 5.7% and 61.3 ± 9.1 bpm, respectively. During a mean follow-up period of 55.8 months, 187 (26.5%) death was observed. A negative linear relationship between PA and RHR was demonstrated in the multiple regression model (β = -0.260; 95% CI: -0.377 to -0.143, p < 0.001). Multivariable Cox proportional hazards analysis showed that both lower levels of PA (HR = 0.907; 95% CI: 0.878-0.936, p < 0.001) and higher RHR (HR = 1.016; 95% CI: 1.001-1.032, P = 0.031) were independent risk factors of all-cause mortality. Causal mediation analysis further confirmed and quantified the mediation function of RHR in the process of PA improving all-cause mortality (mediation proportion = 3.9%; 95% CI: 0.2-10.0%, p = 0.036).Conclusion:The effects of the higher level of PA on improving life prognosis may be partially mediated through RHR among patients with CIED. It indicates that changes in the autonomic nervous function during postoperative rehabilitation exercises should get more attention.

Association of time-varying changes in physical activity with cardiac death and all-cause mortality after ICD or CRT-D implantation.

OBJECTIVE:To evaluate the association of longitudinal changes in physical activity (PA) with long-term outcomes after implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) implantation.METHODS:Patients with ICD/CRT-D implantation from SUMMIT registry were retrospectively analyzed. Accelerometer-derived PA changes over 12 months post implantation were obtained from the archived home monitoring data. The primary endpoints were cardiac death and all-cause mortality. The secondary endpoints were the first ventricular arrthymia (VA) and first appropriate ICD shock.RESULTS:In 705 patients, 446 (63.3%) patients showed improved PA over 12 months after implantation. During a mean 61.5-month follow-up duration, 99 cardiac deaths (14.0%) and 153 all-cause deaths (21.7%) occurred. Compared to reduced/unchanged PA, improved PA over 12 months could result in significantly reduced risks of cardiac death (improved PA ≤ 30 min: hazard ratio (HR) = 0.494, 95% CI: 0.288-0.848; > 30 min: HR = 0.390, 95% CI: 0.235-0.648) and all-cause mortality (improved PA ≤ 30 min: HR = 0.467, 95%CI: 0.299-0.728; > 30 min: HR = 0.451, 95% CI: 0.304-0.669). No differences in the VAs or ICD shocks were observed across different groups of PA changes. PA changes can predict the risks of cardiac death only in the low baseline PA group, but improved PA was associated with 56.7%, 57.4%, and 62.3% reduced risks of all-cause mortality in the low, moderate, and high baseline PA groups, respectively, than reduced/unchanged PA.CONCLUSIONS:Improved PA could protect aganist cardiac death and all-cause mortality, probably reflecting better clinical efficacy after ICD/CRT-D implantation. Low-intensity exercise training might be encouraged among patients with different baseline PA levels.

Clinical Outcomes in Patients With Left Bundle Branch Area Pacing vs. Right Ventricular Pacing for Atrioventricular Block.

Background: Left bundle branch area pacing (LBBAP) is a novel pacing modality with stable pacing parameters and a narrow-paced QRS duration. We compared heart failure (HF) hospitalization events and echocardiographic measures between LBBAP and right ventricular pacing (RVP) in patients with atrioventricular block (AVB). Methods and Results: This multicenter observational study prospectively recruited consecutive AVB patients requiring ventricular pacing in five centers if they received LBBAP or RVP and had left ventricular ejection fraction (LVEF) >50%. Data on electrocardiogram, pacing parameters, echocardiographic measurements, device complications, and clinical outcomes were collected at baseline and during follow-up. The primary outcome was first episode hospitalization for HF or upgrade to biventricular pacing. LBBAP was successful in 235 of 246 patients (95.5%), while 120 patients received RVP. During a mean of 11.4 ± 2.7 months of follow-up, the ventricular pacing burden was comparable (83.9 ± 35.1 vs. 85.7 ± 30.0%), while the mean LVEF differed significantly (62.6 ± 4.6 vs. 57.8 ± 11.4%) between the LBBAP and RVP groups. Patients with LBBAP had significantly lower occurrences of HF hospitalization and upgrading to biventricular pacing than patients with RVP (2.6 vs. 10.8%, P <0.001), and differences in primary outcome between LBBAP and RVP were mainly observed in patients with ventricular pacing >40% or with baseline LVEF <60%. The primary outcome was independently associated with LBBAP (adjusted HR 0.14, 95% CI: 0.04-0.55), previous myocardial infarction (adjusted HR 6.82, 95% CI: 1.23-37.5), and baseline LVEF (adjusted HR 0.91, 95% CI: 0.86-0.96). Conclusion: Permanent LBBAP might reduce the risk of HF hospitalization or upgrade to biventricular pacing compared with RVP in AVB patients requiring a high burden of ventricular pacing. Clinical Trial Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03851315; URL: http://www.chictr.org.cn; Unique Identifier: ChiCTR2100043296.

Comparison of clinical outcomes between transthoracic echocardiography- and X-ray-guided left bundle branch pacing for bradycardia: A randomized controlled trial.

INTRODUCTION:Left bundle branch pacing (LBBP) is a physiological pacing modality. However, the long procedure and fluoroscopy time of LBBP is still a problem. This study aims to compare the clinical outcomes between transthoracic echocardiography (TTE)- and X-ray-guided LBBP.METHODS:This is a single-center, prospective, randomized controlled study. Consecutive patients who underwent LBBP in our team from June 2022 to November 2022 were enrolled. Procedure and fluoroscopy time, pacing parameters, electrophysiological and echocardiographic characteristics, as well as complications were recorded at implantation and during follow-up.RESULTS:In this study, 60 patients were enrolled and divided into two groups: 30 patients were allocated to the X-ray group and the remaining 30 to the TTE group. There was no significant difference in the success rate between the two groups (86.7% vs. 76.7%, p = .317). The procedure time of TTE group was comparable to that of the X-ray group (9.0 vs. 12.0 min, p = .063). However, the fluoroscopy time in the TTE group was significantly lower than that of the X-ray group (2.5 vs. 5.0 min, p = .002). There were no statistically significant differences in pacing parameters, electrophysiological and echocardiographic characteristics, or complications between the two groups at implantation and during follow-up.CONCLUSION:TTE-guided LBBP is a feasible and safe method. Compared with X-ray, TTE showed a comparable success rate and procedure time, but it could significantly reduce the fluoroscopy time of LBBP.

New-onset atrial fibrillation following left bundle branch area pacing vs. right ventricular pacing: a two-centre prospective cohort study.

AIMS:To investigate whether left bundle branch area pacing (LBBAP) can reduce the risk of new-onset atrial fibrillation (AF) compared with right ventricular pacing (RVP).METHODS AND RESULTS:Patients with indications for dual-chamber pacemaker implant and no history of AF were prospectively enrolled if they underwent successful LBBAP or RVP. The primary endpoint was time to the first occurrence of AF detected by pacemaker programming or surface electrocardiogram. Follow-up at clinic visit was performed and multivariate Cox regression models were applied to evaluate the effect of LBBAP on new-onset AF. The final analysis included 527 patients (mean age 65.3 ± 12.6, male 47.3%), with 257 in the LBBAP and 270 in the RVP groups. During a mean follow-up of 11.1 months, LBBAP resulted in significantly lower incidence of new-onset AF (7.4 vs. 17.0%, P < 0.001) and AF burden (3.7 ± 1.9 vs. 9.3 ± 2.2%, P < 0.001) than RVP. After adjusting for confounding factors, LBBAP demonstrated a lower hazard ratio for new-onset AF compared with RVP {hazard ratio (HR) [95% confidence interval (CI)]: 0.278 (0.156, 0.496), P < 0.001}. A significant interaction existed between pacing modalities and the percentage of ventricular pacing (VP%) (P for interaction = 0.020). In patients with VP ≥ 20%, LBBAP was associated with decreased risk of new-onset AF compared with RVP [HR (95% CI): 0.199 (0.105, 0.378), P < 0.001]. The effect of pacing modalities was not pronounced in patients with VP < 20% [HR (95% CI): 0.751 (0.309, 1.823), P = 0.316].CONCLUSION:Left bundle branch area pacing demonstrated a reduced risk of new-onset AF compared with RVP. Patients with a high ventricular pacing burden might benefit from LBBAP.

Tricuspid regurgitation following pacemaker implantation for bradycardia: a two-year study comparing different pacing strategies.

Early left bundle branch pacing in heart failure with mildly reduced ejection fraction and left bundle branch block.

BACKGROUND:Left bundle branch pacing (LBBP) achieves resynchrony and improves cardiac function in heart failure (HF) patients with reduced ejection fraction (EF) by correcting left bundle branch block (LBBB). Few data on the efficacy of early LBBP in HF with mildly reduced EF (HFmrEF) and LBBB have been reported.OBJECTIVE:The purpose of this study was to explore the efficacy of early LBBP in patients with HFmrEF and LBBB.METHODS:Consecutive patients with HFmrEF (left ventricular EF [LVEF] 35%-50%) and LBBB were prospectively enrolled to receive LBBP (Early-LBBP group) plus guideline-directed medical therapy (GDMT) or GDMT alone (GDMT group). Study outcomes included changes in LVEF, LV end-diastolic diameter (LVEDD), New York Heart Association (NYHA) functional classification, and N-terminal pro-brain natriuretic peptide (NT-proBNP), and clinical events (HF rehospitalization or syncope). Subgroup analysis compared efficacy of LBBP between patients with LBBB only without comorbidities or late gadolinium enhancement (LGE) (LBBB-Only group) and patients with either comorbidities or LGE (LBBB-Combined group).RESULTS:Fifty-four patients were enrolled and analyzed (37 Early-LBBP group; 15 GDMT group). LBBP achieved greater improvement in LVEF (+14.75% ± 7.37% vs -2.42% ± 2.84%; P <.001), reduction of LVEDD (-7.51 ± 5.40 mm vs -0.87 ± 4.36 mm; P <.001) and NYHA classification (-0.84 ± 0.76 vs -0.13 ± 0.74; P = .004), and similar reduction of NT-proBNP (-408.83 ± 920.29 pg/mL vs -229.05 ± 1579.17 pg/mL; P = .610) at 6 months. Early LBBP showed significantly reduced clinical events (0.0% vs 40.0%; P <.001) after 20.68 ± 13.55 months of follow-up. Subgroup analysis showed patients in the LBBB-Only group benefited more from LBBP with regard to LVEF improvement and LVEDD reduction than the LBBB-Combined group.CONCLUSION:Early LBBP with GDMT demonstrated greater improvement of cardiac function and reduced clinical events than GDMT alone in patients with HFmrEF and LBBB.

The initial experience of left bundle branch area pacing in patients with hypertrophic cardiomyopathy.

PURPOSE:Whether left bundle branch area pacing (LBBAP) could be achieved in patients with hypertrophic cardiomyopathy (HCM) requiring ventricular pacing remains unknown. The present study aimed to investigate the feasibility and effect of LBBAP in HCM.METHODS:Patients with HCM who underwent LBBAP were recruited from November 2018 to September 2021. Clinical characteristics, echocardiographic, and pacing parameters were prospectively collected at baseline and during follow-up.RESULTS:Eleven consecutive HCM patients who attempted LBBAP were included (mean age 64.0 ± 8.7 years, female 45.5%, mean interventricular septum 16.7 mm). The success rate of LBBAP was 36.4% (4/11) and the reason for failed LBBAP in other seven HCM patients was the inability to screw the lead into the deep septum or capture the left bundle branch. Patients with successful LBBAP had significantly narrower QRS duration than those with failed cases (118.0 ± 3.7 ms vs. 140.9 ± 9.4 ms, p = .01) while the capture thresholds, sensing amplitudes, and pacing impedances were similar. Successful cases presented with less positive late gadolinium enhancement (25.0% vs. 71.4%, p = .02) and thinner interventricular septum thickness (14.5 ± 1.0 mm vs. 18.0 ± 2.5 mm, p = .02) compared with failed cases. Pacing parameters remained stable and no procedure-related complications occurred during a mean follow-up of 8.9 ± 7.3 months.CONCLUSION:LBBAP may be successfully achieved in less than half of HCM patients due to thick interventricular septum and heavy burden of myocardial fibrosis. Pacing strategies should be cautiously considered in patients with HCM.

Tricuspid regurgitation outcomes in left bundle branch area pacing and comparison with right ventricular septal pacing.

Randomized Trial of Left Bundle Branch vs Biventricular Pacing for Cardiac Resynchronization Therapy.

BACKGROUND:Left bundle branch pacing (LBBP) is the most rapidly growing conduction system pacing technique that is capable of correcting intrinsic left bundle branch block (LBBB). As such, it is potentially an optimal alternative to cardiac resynchronization therapy (CRT) with biventricular pacing (BiVP).OBJECTIVES:The authors sought to compare the efficacy of LBBP-CRT with BiVP-CRT in patients with heart failure and reduced left ventricular ejection fraction (LVEF).METHODS:This is a prospective, randomized trial of patients with nonischemic cardiomyopathy and LBBB with 6-month preplanned follow-up. Crossovers were allowed if LBBP or BiVP were unsuccessful. The primary endpoint was the difference in LVEF improvement between 2 groups. The secondary endpoints included changes in echocardiographic measurements, N-terminal pro-B-type natriuretic peptide (NT-proBNP), New York Heart Association functional class, 6-minute walk distance, QRS duration, and CRT response.RESULTS:The study included 40 consecutive patients (20 males, mean age 63.7 years, LVEF 29.7% ± 5.6%). Crossovers occurred in 10% of LBBP-CRT and 20% of BiVP-CRT. All patients completed follow-up. Intention-to-treat analysis showed significantly higher LVEF improvement at 6 months after LBBP-CRT than BiVP-CRT (mean difference: 5.6%; 95% CI: 0.3-10.9; P = 0.039). LBBP-CRT also appeared to have greater reductions in left ventricular end-systolic volume (-24.97 mL; 95% CI: -49.58 to -0.36 mL) and NT-proBNP (-1,071.80 pg/mL; 95% CI: -2,099.40 to -44.20 pg/mL), and comparable changes in New York Heart Association functional class, 6-minute walk distance, QRS duration, and rates of CRT response compared with BiVP-CRT.CONCLUSIONS:LBBP-CRT demonstrated greater LVEF improvement than BiVP-CRT in heart failure patients with nonischemic cardiomyopathy and LBBB. (Left Bundle Branch Pacing Versus Biventricular Pacing for Cardiac Resynchronization Therapy [LBBP-RESYNC]; NCT04110431).

The mediation function of resting heart rate in how physical activity improves all-cause mortality: Continuous and automatic measurement via cardiac implantable electronic devices.

Background:Physical activity (PA) and resting heart rate (RHR) are connected with all-cause mortality. Moreover, there was an inverse correlation between PA and RHR. However, the causal relationship between PA, RHR, and long-term mortality has been rarely evaluated and quantified, particularly the mediation effect of RHR in the association between PA and all-cause mortality.Objective:To describe the relationship between PA and RHR when consistently measured via cardiac implantable electronic devices (CIED) and further explore the mediation effect of PA on all-cause mortality through RHR.Materials and methods:Patients who underwent CIED implantation and received remote home monitoring services were included. During the first 30-60 days after CIED implantation, daily PA and RHR were continuously measured and automatically transmitted by CIED. The primary endpoint was all-cause mortality. The multiple linear regression model was used to confirm the relationship between PA and RHR. The predictive values of both PA and RHR for all-cause mortality were assessed by multivariable Cox proportional hazards models. The causal mediation model was further established to verify and quantify the mediation effect of RHR in the association between PA and all-cause mortality.Results:A total of 730 patients with CIED were included. The mean daily PA and RHR were 10.7 ± 5.7% and 61.3 ± 9.1 bpm, respectively. During a mean follow-up period of 55.8 months, 187 (26.5%) death was observed. A negative linear relationship between PA and RHR was demonstrated in the multiple regression model (β = -0.260; 95% CI: -0.377 to -0.143, p < 0.001). Multivariable Cox proportional hazards analysis showed that both lower levels of PA (HR = 0.907; 95% CI: 0.878-0.936, p < 0.001) and higher RHR (HR = 1.016; 95% CI: 1.001-1.032, P = 0.031) were independent risk factors of all-cause mortality. Causal mediation analysis further confirmed and quantified the mediation function of RHR in the process of PA improving all-cause mortality (mediation proportion = 3.9%; 95% CI: 0.2-10.0%, p = 0.036).Conclusion:The effects of the higher level of PA on improving life prognosis may be partially mediated through RHR among patients with CIED. It indicates that changes in the autonomic nervous function during postoperative rehabilitation exercises should get more attention.

Association of time-varying changes in physical activity with cardiac death and all-cause mortality after ICD or CRT-D implantation.

OBJECTIVE:To evaluate the association of longitudinal changes in physical activity (PA) with long-term outcomes after implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) implantation.METHODS:Patients with ICD/CRT-D implantation from SUMMIT registry were retrospectively analyzed. Accelerometer-derived PA changes over 12 months post implantation were obtained from the archived home monitoring data. The primary endpoints were cardiac death and all-cause mortality. The secondary endpoints were the first ventricular arrthymia (VA) and first appropriate ICD shock.RESULTS:In 705 patients, 446 (63.3%) patients showed improved PA over 12 months after implantation. During a mean 61.5-month follow-up duration, 99 cardiac deaths (14.0%) and 153 all-cause deaths (21.7%) occurred. Compared to reduced/unchanged PA, improved PA over 12 months could result in significantly reduced risks of cardiac death (improved PA ≤ 30 min: hazard ratio (HR) = 0.494, 95% CI: 0.288-0.848; > 30 min: HR = 0.390, 95% CI: 0.235-0.648) and all-cause mortality (improved PA ≤ 30 min: HR = 0.467, 95%CI: 0.299-0.728; > 30 min: HR = 0.451, 95% CI: 0.304-0.669). No differences in the VAs or ICD shocks were observed across different groups of PA changes. PA changes can predict the risks of cardiac death only in the low baseline PA group, but improved PA was associated with 56.7%, 57.4%, and 62.3% reduced risks of all-cause mortality in the low, moderate, and high baseline PA groups, respectively, than reduced/unchanged PA.CONCLUSIONS:Improved PA could protect aganist cardiac death and all-cause mortality, probably reflecting better clinical efficacy after ICD/CRT-D implantation. Low-intensity exercise training might be encouraged among patients with different baseline PA levels.

Clinical Outcomes in Patients With Left Bundle Branch Area Pacing vs. Right Ventricular Pacing for Atrioventricular Block.

Background: Left bundle branch area pacing (LBBAP) is a novel pacing modality with stable pacing parameters and a narrow-paced QRS duration. We compared heart failure (HF) hospitalization events and echocardiographic measures between LBBAP and right ventricular pacing (RVP) in patients with atrioventricular block (AVB). Methods and Results: This multicenter observational study prospectively recruited consecutive AVB patients requiring ventricular pacing in five centers if they received LBBAP or RVP and had left ventricular ejection fraction (LVEF) >50%. Data on electrocardiogram, pacing parameters, echocardiographic measurements, device complications, and clinical outcomes were collected at baseline and during follow-up. The primary outcome was first episode hospitalization for HF or upgrade to biventricular pacing. LBBAP was successful in 235 of 246 patients (95.5%), while 120 patients received RVP. During a mean of 11.4 ± 2.7 months of follow-up, the ventricular pacing burden was comparable (83.9 ± 35.1 vs. 85.7 ± 30.0%), while the mean LVEF differed significantly (62.6 ± 4.6 vs. 57.8 ± 11.4%) between the LBBAP and RVP groups. Patients with LBBAP had significantly lower occurrences of HF hospitalization and upgrading to biventricular pacing than patients with RVP (2.6 vs. 10.8%, P <0.001), and differences in primary outcome between LBBAP and RVP were mainly observed in patients with ventricular pacing >40% or with baseline LVEF <60%. The primary outcome was independently associated with LBBAP (adjusted HR 0.14, 95% CI: 0.04-0.55), previous myocardial infarction (adjusted HR 6.82, 95% CI: 1.23-37.5), and baseline LVEF (adjusted HR 0.91, 95% CI: 0.86-0.96). Conclusion: Permanent LBBAP might reduce the risk of HF hospitalization or upgrade to biventricular pacing compared with RVP in AVB patients requiring a high burden of ventricular pacing. Clinical Trial Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03851315; URL: http://www.chictr.org.cn; Unique Identifier: ChiCTR2100043296.