T-Wave oversensing (TWOS) is a type of pacemaker malfunction that can result in inappropriate tachyarrhythmia detection and loss of pacing, attenuating potential benefits of cardiac resynchronization therapy (CRT). We present a case series of TWOS after left bundle branch pacing (LBBP) in the First Affiliated Hospital of Nanjing Medical University from 2020 to 2024. By analyzing underlying mechanisms and summarizing feasible solutions, we highlight the particularity and complexity of TWOS. It can occur immediately after procedure or be detected after a relatively long period of time. The harm of TWOS should be dealt with in a timely manner.

Obesity-related cardiomyopathy (OCM) is characterized by pathological cardiac remodeling and progressive functional decline, often accompanied by mitochondrial dysfunction, particularly aberrant mitophagy. The role of the core circadian gene brain and muscle ARNT-like protein 1 ( Bmal1) in OCM remains unclear. In this study, we employed a high-fat diet (HFD)-induced OCM mouse model, a cardiomyocyte-specific Bmal1 knockout ( Bmal1 CMKO) model, and a palmitic acid (PA)-induced H9c2 cardiomyocyte injury model to investigate the function of Bmal1. In vivo, BMAL1 expression was reduced in hearts of HFD mice; HFD- Bmal1 CMKO mice exhibited exacerbated myocardial hypertrophy, fibrosis, functional impairment, and apoptosis, accompanied by increased expression of the mitophagy-related proteins PINK1, Parkin, and LC3-II. In vitro, PA exposure decreased BMAL1 expression, disrupted mitochondrial membrane potential, increased reactive oxygen species generation, and induced excessive mitophagy; these effects were aggravated by Bmal1 silencing and attenuated by Bmal1 overexpression, which also improved cell viability. Collectively, these findings indicate that Bmal1 plays a protective role in OCM, and its downregulation may be a key contributor to obesity-induced cardiac remodeling and dysfunction. Mechanistically, BMAL1 downregulation was accompanied by activation of the PINK1/Parkin signaling and enhanced mitophagy under lipid stress. By restraining excessive mitophagy and preserving mitochondrial function and metabolic homeostasis, Bmal1 and its associated pathways may represent promising therapeutic targets for OCM.

BACKGROUND:Pacing-induced cardiomyopathy (PICM) is a serious complication associated with right ventricular pacing. This study aims to identify patients at a high risk for PICM and mitigate its incidence by guiding the selection of left bundle branch pacing over right ventricular pacing. METHODS:Consecutive patients who underwent permanent right ventricular pacing at two centers from January 2013 to December 2022 were retrospectively evaluated. They were used as the derivation set and the validation set, respectively. Clinical, echocardiographic, and electrocardiographic data were collected at baseline and during follow-up. Two models were developed using selected variables obtained through two different methods, and the superior model was chosen based on its simplicity and performance. Based on the selected model, a nomogram was constructed, evaluated, and externally validated using the validation set. RESULTS:The derivation set comprised 374 patients, with 74 (19.8%) diagnosed with PICM. The final Cox model incorporated ejection fraction, left ventricular end-systolic diameter, baseline QRS duration, and atrial fibrillation status (present/absent). The nomogram based on this model demonstrated moderate discrimination, achieving a C statistic of 0.75 (95% confidence interval: 0.70-0.81). The calibration curve showed accurate risk predictions for PICM. Its performance was consistent during internal validation via bootstrapping and was maintained in the validation set. The model effectively stratified risk, distinguishing between high-risk and low-risk populations. CONCLUSION:A user-friendly tool effectively predicts 3-, 5-, and 8-year risk of PICM in patients with right ventricular pacing and normal ejection fraction. It may help identify patients most likely to benefit from left bundle branch pacing versus right ventricular pacing, guiding initial pacing strategy selection.

AIMS:Left bundle branch pacing is effective for cardiac resynchronization therapy (CRT), but the role of left ventricular septal pacing (LVSP) for CRT remains controversial due to lack of LBB capture. We hypothesized that combining LVSP with LV pacing (LVP) may provide additional benefits. METHODS AND RESULTS:This prospective observational study enrolled consecutive patients undergoing LVSP for CRT. LVSP was acceptable if paced QRS duration (QRSd)＜130 ms or QRSd reduction ≥ 20%. If neither criterion were met, a CS-LV lead was implanted. Acute hemodynamic response (AHR) represented by LV maximum first derivative (dP/dtmax) was accessed. All patients were followed up for echocardiographic parameters, NT-proBNP levels, NYHA classes, and clinical events. The clinical outcomes included all-cause mortality, heart failure hospitalization, and ventricular tachyarrhythmias. A total of 45 patients achieved left bundle branch area pacing (LBBAP) without confirmed LBB capture were enrolled, including 25 with LVSP alone and 20 with LVSP + LVP. QRSd reduction was significantly greater in LVSP + LVP than LVSP (46.2 ± 19.2 ms vs. 32.6 ± 23.0 ms, P = 0.049). LVSP + LVP resulted in greater improvement in AHR than LVSP (20.0 ± 9.2% vs. 10.4 ± 8.2%, P＜0.001) in 10 patients. After a median follow-up of 26-month, LVEF improvement was significantly higher in LVSP + LVP than LVSP (mean difference: 3.05%; 95% CI: 0.05-6.05; P = 0.047). LVSP + LVP was also independently associated with 87% lower risk of clinical outcomes compared with LVSP [aHR: 0.13 (0.03, 0.62), P = 0.011]. CONCLUSION:LVSP combined with LVP might offer greater AHR, electrical resynchronization and as well as improved clinical outcomes than LVSP alone in patients undergoing LBBAP-CRT without LBB capture.

BACKGROUND:The segment of the latest mechanical contraction (LMC) does not always overlap with the site of the latest electrical activation (LEA). By integrating both mechanical and electrical dyssynchrony, this proof-of-concept study aimed to propose a new method for recommending left ventricular (LV) lead placements, with the goal of enhancing response to cardiac resynchronization therapy (CRT). METHODS:The LMC segment was determined by single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI) phase analysis. The LEA site was detected by vectorcardiogram. The recommended segments for LV lead placement were as follows: (1) the LMC viable segments that overlapped with the LEA site; (2) the LMC viable segments adjacent to the LEA site; (3) If no segment met either of the above, the LV lateral wall was recommended. The response was defined as ≥15% reduction in left ventricular end-systolic volume (LVESV) 6-months after CRT. Patients with LV lead located in the recommended site were assigned to the recommended group, and those located in the non-recommended site were assigned to the non-recommended group. RESULTS:The cohort comprised of 76 patients, including 54 (71.1%) in the recommended group and 22 (28.9%) in the non-recommended group. Among the recommended group, 74.1% of the patients responded to CRT, while 36.4% in the non-recommended group were responders (P = .002). Compared to pacing at the non-recommended segments, pacing at the recommended segments showed an independent association with an increased response by univariate and multivariable analysis (odds ratio 5.00, 95% confidence interval 1.73-14.44, P = .003; odds ratio 7.33, 95% confidence interval 1.53-35.14, P = .013). Kaplan-Meier curves showed that pacing at the recommended LV lead position demonstrated a better long-term prognosis. CONCLUSION:Our findings indicate that pacing at the recommended segments, by integrating of mechanical and electrical dyssynchrony, is significantly associated with an improved CRT response and better long-term prognosis.

The obstacles to the continuous cropping of Chinese herbs in Yunnan have become increasingly prominent. Many soil-borne diseases can infect the roots of crops, affect the growth of crops, and eventually lead to quality and yield reduction. Soil steam disinfection can still be used as one of the first methods to solve the problem of continuous cropping obstacles of Chinese herbs such as Panax notoginseng. However, the steam will condense into a large amount of liquid water when it is cold, which will cause soil pore blockage and seriously affect the steam diffusion efficiency. Therefore, it is necessary to study the influence mechanism of the pore structure of Yunnan red loam on heat and mass transfer of steam disinfection. The experimental research was conducted on steam disinfection's heat and mass transfer patterns under different soil pore structure conditions. Image processing technology was used to collect accurate soil profiles and to establish real soil pore structure analysis. Then, fluid simulation technology was used to simulate the heat and mass transfer process and trend of steam distribution within the soil profile under different soil pore structures. The results showed that the steam heat flow of <2 mm, 2-4 mm and 4-6 mm treatments were uniformly diffused in the form of matrix flow in a 1/4 ellipse, and the effective disinfection range was 18 cm horizontal distance and 20 cm vertical distance, in which the highest temperature could reach more than 90degree celsius. The steam heat flow of the 6-8 mm and >8 mm treatment groups diffused irregularly in large pore steam flow. Therefore, some devices for breaking soil and rotary tillage need to finely rotate the soil in the future. The end effector's disinfection pipe spacing can refer to the effective disin-fection range.

BackgroundLeft bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) are referred to as left bundle branch area pacing (LBBAP).ObjectiveThis study investigated whether long-term clinical outcomes differ in patients undergoing LBBP, LVSP, and biventricular pacing (BiVP) for cardiac resynchronization therapy (CRT).MethodsConsecutive patients with reduced left ventricular ejection fraction (LVEF<50%) undergoing CRT were prospectively enrolled if they underwent successful LBBP, LVSP, or BiVP. The primary composite endpoint was all-cause mortality or heart failure hospitalization (HFH). Secondary endpoints included all-cause mortality, HFH, and echocardiographic measures of reverse remodeling.ResultsA total of 259 patients (68 LBBP, 38 LVSP, and 153 BiVP) were followed for a mean duration of 28.8 ± 15.8 months. LBBP was associated with a significantly reduced risk of the primary endpoint by 78% compared to both BiVP [7.4% vs. 41.2%; adjusted hazard ratio (aHR) 0.22 (0.08, 0.57), p=0.002] and LVSP [7.4% vs. 47.4%; aHR 0.22 (0.08, 0.63), p=0.004]. The adjusted risk of all-cause mortality was significantly higher in LVSP than BiVP [31.6% vs. 7.2%, aHR 3.19 (1.38, 7.39); p=0.007] but comparable between LBBP and BiVP [2.9% vs. 7.2%, aHR 0.33 (0.07, 1.52), p=0.155]. Propensity score adjustment also obtained similar results. LBBP showed a higher rate of echocardiographic response (ΔLVEF ≥10%: 60.0% vs. 36.2% vs. 16.1%; p<0.001) than BiVP or LVSP.ConclusionLBBP yielded superior long-term clinical outcomes to BiVP and LVSP. The role of LVSP for CRT needs to be reevaluated due to its high mortality risk.

Patients with heart failure with mildly-reduced ejection fraction (HFmrEF) and left bundle branch block (LBBB) have worse outcomes than those without intraventricular conduction abnormality. Current guidelines only recommend cardiac resynchronization therapy (CRT) when LVEF is less than 35%. Left bundle branch pacing (LBBP) has been shown to better restore electrical synchrony and improve cardiac function than conventional biventricular CRT in HFrEF. Its efficacy in HFmrEF is rarely reported.