Heart Block

BackgroundLeft bundle branch area pacing (LBBAP) may be an alternative to biventricular pacing (BVP) for cardiac resynchronization therapy (CRT). We sought to compare the acute hemodynamic and ECG effects of LBBAP, BVP, and left bundle-optimized therapy CRT (LOT-CRT) in CRT candidates with advanced conduction disease.MethodsIn this multicenter study, 48 patients with either nonspecific interventricular conduction delay (n=29) or left bundle branch block (n=19) underwent acute hemodynamic testing to determine the change in left ventricular pressure maximal first derivative (LV dP/dtmax) from baseline atrial pacing to BVP, LBBAP, or LOT-CRT.ResultsAtrioventricular-optimized increases in LV dP/dtmax for LOT-CRT (mean, 25.8% [95% CI, 20.9%-30.7%]) and BVP (26.4% [95% CI, 20.2%-32.6%]) were greater than unipolar LBBAP (19.3% [95% CI, 15.0%-23.7%]) or bipolar LBBAP (16.4% [95% CI, 12.7%-20.0%]; P≤0.005). QRS shortening was greater in LOT-CRT (29.5 [95% CI, 23.4-35.6] ms) than unipolar LBBAP (11.9 [95% CI, 6.1-17.7] ms), bipolar LBBAP (11.7 ms [95% CI, 6.4-17.0]), or BVP (18.5 [95% CI, 11.0-25.9] ms), all P≤0.005. Compared with patients with left bundle branch block, patients with interventricular conduction delay experienced less QRS reduction (P=0.026) but similar improvements in LV dP/dtmax (P=0.29). Bipolar LBBAP caused anodal capture in 54% of patients and resulted in less LV dP/dtmax improvement than unipolar LBBAP (18.6% versus 23.7%; PP=0.031) and success of LBBAP (PP/dtmax improvement and 20.8 (12.8-28.8) ms greater QRS shortening than LBBAP in subjects with QRS ≥171 ms and deep septal pacing capture type.ConclusionsIn a CRT cohort with advanced conduction disease, LOT-CRT and BVP provided greater acute hemodynamic benefit than LBBAP. Subjects with wider QRS or deep septal pacing are more likely to benefit from the addition of a left ventricular coronary vein lead to implement LOT-CRT.RegistrationURL: https://www.clinicaltrials.gov; Unique identifier: NCT04905290.

Sick sinus syndrome (SSS), also known as sinoatrial node dysfunction, has been widely concerned by the medical community. The incidence rate of SSS is increasingly, which poses a great threat to public health. Through decades of repeated research in the medical field, great progress has been made in the pathogenesis of SSS and the interaction mechanism between SSS and other cardiovascular diseases. In this paper, we pay special attention to the mental stimulation factors under various pressures such as society and work, and the influence of smoking, drinking, and unhealthy diet on the pathogenesis of SSS. It also explains the mechanism of negative factors in the pathogenesis of SSS. These unhealthy lifestyle will lead to the occurrence of sinoatrial node disease and arrhythmia, and then induce SSS. Therefore, in the premise of increasing incidence rate of SSS and difficult to cure, how to avoid these harmful factors and ensure a healthy lifestyle is extremely important for preventing and treating SSS. This study also has guiding significance for the daily life of high-risk population of SSS and reducing the mortality of SSS patients.

ImportanceAlthough a high body mass index (BMI) has been found to be associated with increased risk of cardiac conduction block (CCB) in older adults, no further studies have investigated the association between obesity and CCB in the general population.ObjectiveTo investigate the association between obesity and CCB, including its subtypes.Design, setting, and participantsThis cohort study used data from participants in the Kailuan Study in China (2006-2018) who had completed a physical examination in 2006 (baseline) and had not experienced CCB before baseline. Data analysis was conducted from March to September 2023.ExposuresObesity status was defined by BMI in 3 groups: normal weight (18.5 to Main outcome and measuresThe primary outcome was CCB, which was diagnosed from standard 12-lead electrocardiography. The primary end point included high-grade atrioventricular block (HAVB), complete right bundle branch block, complete left bundle branch block, left anterior fascicular block (LAFB), and left posterior fascicular block. First-degree atrioventricular block (FAVB), second-degree type 1 AVB, HAVB, complete and incomplete right and left bundle branch block, LAFB, and left posterior fascicular block were considered separately as secondary end points.ResultsAmong 86 635 participants (mean [SD] age, 50.8 [11.9] years; 68 205 males [78.7%]), there were 33 259 individuals with normal weight (38.4%), 37 069 individuals with overweight (42.8%), and 16 307 individuals with obesity (18.8%). The mean (SD) follow-up was 10.6 (3.07) years. In the multivariable Cox proportional hazards regression analysis, obesity was associated with an increased risk of incident CCB (hazard ratio [HR], 1.21; 95% CI, 1.04-1.42) vs normal BMI. In secondary analysis, obesity was associated with an increased risk of FAVB (HR, 1.44; 95% CI, 1.21-1.73), HAVB (HR, 1.99; 95% CI, 1.03-3.82), and LAFB (HR, 1.29; 95% CI, 1.03-1.62) vs normal BMI. There was no association between obesity and other CCB subtypes. Obesity was associated with a greater increase in risk of CCB vs normal BMI in older (aged ≥65 years; HR, 1.44; 95% CI, 1.05-1.96) vs younger (aged Conclusions and relevanceThis study found that obesity was associated with an increased risk of CCB, with greater increases in risk for FAVB, HAVB, and LAFB. Individuals who were older and those who had diabetes had larger increases in risk.

ImportanceLeft bundle-branch pacing (LBBP) has been proposed as an alternative to biventricular pacing (BiVP) for patients with heart failure with left bundle-branch block (LBBB). However, robust clinical evidence from randomized clinical trials is lacking.ObjectiveTo evaluate the long-term clinical outcomes of LBBP and BiVP.Design, setting, and participantsThis multicenter, prospective, randomized clinical trial enrolled 200 patients at 6 centers in China with a left ventricular ejection fraction (LVEF) of 35% or less and LBBB from October 2020 to March 2022. This study was took place from October 2020 to September 2024. These data were analyzed September 2024 to December 2024.InterventionsPatients were randomly assigned in a 1:1 ratio to receive either LBBP or BiVP.Main outcomes and measuresThe primary end point was the time to death from any cause or heart failure hospitalization (HFH). The secondary end points included all-cause death, HFH, echocardiographic response (absolute increase in LVEF ≥5%), and super response (absolute increase in LVEF ≥15% or improvement of LVEF to ≥50%) rates.ResultsOf the 200 included patients, 136 were male and 64 were female. The success rate was 98% in the LBBP group and 94% in the BiVP group (P = .28). The median follow-up duration was 36 (range, 33-39) months. The primary end point of time to death or HFH was significantly lower in the LBBP group compared with BiVP (8% vs 28%; hazard ratio [HR], 0.26; 95% CI, 0.12-0.57; P Conclusions and relevanceIn this study, LBBP was superior to BiVP in reducing the risk of death or HFH in patients with LBBB and severely reduced LVEF. Further trials are warranted in this patient population.Trial registrationChinese Clinical Trial Registry identifier: ChiCTR2000036554.