Feasibility, safety and outcomes of conduction system pacing for bradycardia amongst the very elderly.

The impact of age (≥ 85 vs < 85 years) on clinical outcomes and pacemaker performance of conduction system pacing (CSP) compared to right ventricular pacing (RVP) were examined. Consecutive patients from a prospective, observational, multicenter study with pacemakers implanted for bradycardia were studied. The primary endpoint was a composite of heart failure (HF)-hospitalizations, pacing-induced cardiomyopathy requiring cardiac resynchronization therapy or all-cause mortality. Secondary endpoints were acutely successful CSP, absence of pacing-complications, optimal pacemaker performance defined as pacing thresholds < 2.5 V, R-wave amplitude ≥ 5 V and absence of complications, threshold stability (no increases of > 1 V) and persistence of His-Purkinje capture on follow-up. Among 984 patients (age 74.1 ± 11.2 years, 41% CSP, 16% ≥ 85 years), CSP was independently associated with reduced hazard of the primary endpoint compared to RVP, regardless of age-group (< 85 years: adjusted hazard ratio [AHR] 0.63, 95% confidence interval [CI] 0.40-0.98; ≥ 85 years: AHR 0.40, 95% CI 0.17-0.94). Among patients with CSP, age did not significantly impact the secondary endpoints of acute CSP success (86% vs 88%), pacing complications (19% vs 11%), optimal pacemaker performance (64% vs 69%), threshold stability (96% vs 96%) and persistent His-Purkinje capture (86% vs 91%) on follow-up (all p > 0.05). CSP improves clinical outcomes in all age-groups, without compromising procedural safety or pacemaker performance in the very elderly.

Prognostic benefits of His-Purkinje capture in physiological pacemakers for bradycardia.

INTRODUCTION: Clinical outcomes of long-term ventricular septal pacing (VSP) without His-Purkinje capture remain unknown. This study evaluated the differences in clinical outcomes between conduction system pacing (CSP), VSP, and right ventricular pacing (RVP). METHODS: Consecutive patients with bradycardia indicated for pacing from 2016 to 2022 were prospectively followed for the clinical endpoints of heart failure (HF)-hospitalizations and all-cause mortality at 2 years. VSP was defined as septal pacing due to unsuccessful CSP implant or successful CSP followed by loss of His-Purkinje capture within 90 days. RESULTS: Among 1016 patients (age 73.9 ± 11.2 years, 47% female, 48% atrioventricular block), 612 received RVP, 335 received CSP and 69 received VSP. Paced QRS duration was similar between VSP and RVP, but both significantly longer than CSP (p < .05). HF-hospitalizations occurred in 130 (13%) patients (CSP 7% vs. RVP 16% vs. VSP 13%, p = .001), and all-cause mortality in 143 (14%) patients (CSP 7% vs. RVP 19% vs. VSP 9%, p < .001). The association of pacing modality with clinical events was limited to those with ventricular pacing (Vp) > 20% (pinteraction < .05). Adjusting for clinical risk factors among patients with Vp > 20%, VSP (adjusted hazard ratio [AHR]: 4.74, 95% confidence interval [CI]: 1.57-14.36) and RVP (AHR: 3.08, 95% CI: 1.44-6.60) were associated with increased hazard of HF-hospitalizations, and RVP (2.52, 95% CI: 1.19-5.35) with increased mortality, compared to CSP. Clinical endpoints did not differ between VSP and RVP with Vp > 20%, or amongst groups with Vp < 20%. CONCLUSION: Conduction system capture is associated with improved clinical outcomes. CSP should be preferred over VSP or RVP during pacing for bradycardia.

Chiral anomaly and Weyl orbit in three-dimensional Dirac semimetal Cd3As2grown on Si.

Preparing Cd3As2, which is a three-dimensional (3D) Dirac semimetal in certain crystal orientation, on Si is highly desirable as such a sample may well be fully compatible with existing Si CMOS technology. However, there is a dearth of such a study regarding Cd3As2films grown on Si showing the chiral anomaly. Here,for the first time, we report the novel preparation and fabrication technique of a Cd3As2(112) film on a Si (111) substrate with a ZnTe (111) buffer layer which explicitly shows the chiral anomaly with a nontrivial Berry's phase ofπ. Despite the Hall carrier density (n3D≈9.42×1017cm-3) of our Cd3As2film, which is almost beyond the limit for the portents of a 3D Dirac semimetal to emerge, we observe large linear magnetoresistance in a perpendicular magnetic field and negative magnetoresistance in a parallel magnetic field. These results clearly demonstrate the chiral magnetic effect and 3D Dirac semimetallic behavior in our silicon-based Cd3As2film. Our tailoring growth of Cd3As2on a conventional substrate such as Si keeps the sample quality, while also achieving a low carrier concentration.

Comparison of Pacing Performance and Clinical Outcomes Between Left Bundle Branch and His Bundle Pacing.

BACKGROUND: Left bundle branch (LBBP) and His-bundle pacing (HBP) provide physiological ventricular activation. OBJECTIVES: This study investigated differences in feasibility, device performance, and clinical outcomes between LBBP and HBP. METHODS: Consecutive patients with LBBP and HBP from 2018 to 2021 in 2 centers were prospectively studied. The primary endpoint was optimal device performance during follow-up, defined as the presence of pacing thresholds <2.5 V, R-wave amplitude ≥5 V, and absence of conduction system pacing (CSP)-related complications. The secondary endpoint was the composite of heart failure hospitalizations or all-cause mortality. RESULTS: Among 338 patients, 282 underwent successful CSP (119 HBP, 163 LBBP). Success rates, CSP-related complications, and need for reoperations did not differ between LBBP and HBP (P > 0.05). Pacing thresholds were lower, whereas R-wave amplitudes and lead impedance were higher in LBBP (P < 0.05). The primary endpoint was more frequent in LBBP than HBP (79% vs 34%; P < 0.001), with LBBP independently associated with 9-fold increased odds of optimal device performance (adjusted OR: 9.31; 95% CI: 5.14-16.86). LBBP was less likely to have increased pacing thresholds by >1 V (1% vs 19% HBP, P < 0.001). The secondary outcome was less frequent in LBBP than HBP (9% vs 24%, P = 0.001), with LBBP trending towards higher event-free survival (HR: 0.62; 95% CI: 0.31-1.23). The secondary outcome was independent of pacing burden or pacing indication. CONCLUSIONS: Despite similar feasibility and safety profiles, LBBP confers additional benefits in pacing performance and reliability, shows trends towards improved survival compared to HBP, and should be the preferred first-line CSP modality of choice.

The recovery strategies to support cervical cancer elimination in lower-and middle-income countries (LMICs) following COVID-19 disruptions.

The COVID-19 pandemic has exacerbated the existing challenges to achieving the WHO target of eliminating cervical cancer as a public health problem by working towards the target of fewer than four cases per 100 000 women. We reviewed the literature to identify potential recovery strategies to support cervical cancer prevention programs in lower-and middle-income countries (LMICs) following COVID-19 disruptions and the extent to which strategies have been implemented. Utilising the WHO health systems framework, we mapped these recovery strategies against the six building blocks to examine their reach across the health system. Most recovery strategies were focused on service delivery, while leadership and governance played a pivotal role in the continuity of cervical cancer prevention programs during the pandemic. Leadership and governance were the drivers for outcomes in the building blocks of health information systems, financing and critical support in operationalising service delivery strategies. In the aftermath of the COVID-19 pandemic with strained health resources and economies, stakeholders would significantly influence the coverage and sustainability of cervical cancer prevention programs. The support from multisectoral stakeholders would accelerate the recovery of cervical cancer prevention programs. To achieve the WHO target by 2030, we call for future studies to understand the barriers and facilitators from the perspectives of stakeholders in order to support the decision-making processes and information required to implement recovery strategies in LMICs.

Conduction system versus biventricular pacing in heart failure with non-left bundle branch block.

INTRODUCTION: The benefits of cardiac resynchronization therapy (CRT) with biventricular pacing (BiV) is significantly lower when applied to heart failure (HF) patients with non-left bundle branch block (LBBB) conduction delay. We investigated clinical outcomes of conduction system pacing (CSP) for CRT in non-LBBB HF. METHODS: Consecutive HF patients with non-LBBB conduction delay undergoing CSP were propensity matched for age, sex, HF-etiology, and atrial fibrillation (AF) in a 1:1 ratio to BiV from a prospective registry of CRT recipients. Echocardiographic response was defined as an increase in left ventricular ejection fraction (LVEF) by ≥10%. The primary outcome was the composite of HF-hospitalizations or all-cause mortality. RESULTS: A total of 96 patients were recruited (mean age 70 ± 11years, 22% female, 68% ischemic HF and 49% AF). Significant reductions in QRS duration and LV dimensions were seen only after CSP, while LVEF improved significantly in both groups (p < 0.05). Echocardiographic response occurred more frequently in CSP than BiV (51% vs. 21%, p < 0.01), with CSP independently associated with four-fold increased odds (adjusted odds ratio 4.08, 95% confidence interval [CI] 1.34-12.41). The primary outcome occurred more frequently in BiV than CSP (69% vs. 27%, p < 0.001), with CSP independently associated with 58% risk reduction (adjusted hazard ratio [AHR] 0.42, 95% CI 0.21-0.84, p = 0.01), driven by reduced all-cause mortality (AHR 0.22, 95% CI 0.07-0.68, p < 0.01), and a trend toward reduced HF-hospitalization (AHR 0.51, 95% CI 0.21-1.21, p = 0.12). CONCLUSIONS: CSP provided greater electrical synchrony, reverse remodeling, improved cardiac function and survival compared to BiV in non-LBBB, and may be the preferred CRT strategy for non-LBBB HF.

Clinical Outcomes in Conduction System Pacing Compared to Right Ventricular Pacing in Bradycardia.

BACKGROUND: Conduction system pacing (CSP) provides more physiological ventricular activation than right ventricular pacing (RVP). OBJECTIVES: This study evaluated the differences in clinical outcomes in patients receiving CSP and RVP. METHODS: Consecutive patients with pacemakers implanted for bradycardia from 2016 to 2021 in 2 centers were prospectively followed for the primary composite outcome of heart failure (HF) hospitalizations, upgrade to biventricular pacing, or all-cause mortality, stratified by ventricular pacing burden (Vp) . RESULTS: Among 860 patients (mean age 74 ± 11 years, 48% female, 48% atrioventricular block), 628 received RVP and 231 received CSP (95 His-bundle pacing, 136 left bundle branch pacing). The primary outcome occurred in 217 (25%) patients, more commonly in patients with RVP than CSP (30% vs 13%, P < 0.001). In multivariable analyses, CSP was independently associated with 47% reduction of the primary outcome (adjusted hazard ratio [AHR]: 0.53; 95% CI: 0.29-0.97; P = 0.04) and HF hospitalization alone (AHR: 0.40; 95% CI: 0.17-0.95; P = 0.04), among only patients with Vp >20%. The incidence of the primary outcome was highest among RVP with Vp >20% and lowest in CSP with Vp >20% (35% vs 10%, P < 0.001). Compared with RVP with Vp >20%, both CSP with Vp >20% (AHR: 0.51; 95% CI: 0.28-0.91; P = 0.02) and all patients with Vp ≤20% (AHR: 0.73; 95% CI: 0.54-0.99; P = 0.04) were independently associated with reduced primary outcome, driven primarily by reductions in HF hospitalizations (P < 0.05). Event-free survival was similar between CSP with Vp >20% and those needing ≤20% Vp. CONCLUSIONS: CSP significantly reduced adverse clinical outcomes for bradycardic patients requiring ventricular pacing and should be the preferred pacing modality of choice.

Use of extendable helix leads for conduction system pacing: Differences in lead handling and performance lead design impacts conduction system pacing.

INTRODUCTION: Pacing leads with extendable-retractable helix (EHL) are alternatives to fixed-helix leads (FHL) for conduction system pacing (CSP), but data on handling characteristics are limited. This study evaluated a dual-center experience of lead handling and performance during CSP. METHODS AND RESULTS: Consecutive patients with His-bundle pacing (HBP) or left bundle branch pacing (LBBP) were evaluated for the primary outcome of lead failure, defined as structural damage to the lead necessitating lead replacement. Differences in pacing characteristics were compared. Among 280 patients (mean age 74 ± 11 years, 44% male, 50% LBBP), 246 (88%) received FHL and 34 (12%) received EHL. Of 299 leads used, lead failure occurred more frequently among patients with EHL than FHL (29% vs. 2%, p < .001), regardless of CSP modality. Majority of damaged leads (89%) in the form of helix deformation were successfully removed, with failure occurring in only two patients, both EHL, leading to helix fracture and retention within the septal myocardium. EHL, compared to FHL, was associated with 25-fold increased odds of lead failure (odds ratio: 25.21, 95% confidence interval: 7.35-86.51), and persisted after adjustment in turn for age, pacing modality and indication. CSP implant success rates did not differ by lead design (FHL 80% vs. EHL 71%, p = .18), with similar pacing thresholds at implant and follow-up. CONCLUSION: Helix deformation and fracture were more frequent with EHL in CSP despite similar implant success. These findings have significant implications for lead selection during CSP and raises concerns about the long-term extractability of EHL in CSP.

A First Reported Adjustable Breast Volume Simulator for Teaching Oncoplastic Surgery Marking: Adjustable Breast Oncoplastic Surgery Simulator.

BACKGROUND: The current simulators for teaching oncoplastic surgery marking are available in a fixed size for each model. This is not an accurate reflection of the variety of patient's breast volumes in reality and may limit the teaching to certain techniques associated with the particular breast ptosis/size. DEVICE DESCRIPTION: This is the first reported simulator with varying breast volumes/ptosis in a single model for teaching oncoplastic surgery marking, known as Adjustable Breast Oncoplastic Surgery Simulator (ABOSS). Adjustable Breast Oncoplastic Surgery Simulator was created using 3D printing. PRELIMINARY RESULTS: Adjustable Breast Oncoplastic Surgery Simulator could simulate the breast in appearance and texture. It is inexpensive and allows the practice of various markings based on the different breast volumes/ptosis in a single model. It also allows for the practice of the marking needed in asymmetric breasts to correct the asymmetry. CURRENT STATUS: Plans for commercialisation were made.

Machine Learning-Guided Prediction of Central Anterior Chamber Depth Using Slit Lamp Images from a Portable Smartphone Device.

There is currently no objective portable screening modality for narrow angles in the community. In this prospective, single-centre image validation study, we used machine learning on slit lamp images taken with a portable smartphone device (MIDAS) to predict the central anterior chamber depth (ACD) of phakic patients with undilated pupils. Patients 60 years or older with no history of laser or intraocular surgery were recruited. Slit lamp images were taken with MIDAS, followed by anterior segment optical coherence tomography (ASOCT; Casia SS-1000, Tomey, Nagoya, Japan). After manual annotation of the anatomical landmarks of the slit lamp photos, machine learning was applied after image processing and feature extraction to predict the ACD. These values were then compared with those acquired from the ASOCT. Sixty-six eyes (right = 39, 59.1%) were included for analysis. The predicted ACD values formed a strong positive correlation with the measured ACD values from ASOCT (R2 = 0.91 for training data and R2 = 0.73 for test data). This study suggests the possibility of estimating central ACD using slit lamp images taken from portable devices.

A sustainable model for raising colposcopy expertise in low-to-middle-income countries.

OBJECTIVE: The objective of the study was to assess the effectiveness of training low-to-middle-income countries' local healthcare providers using the Train-the-trainers model in basic colposcopy for cervical cancer prevention. METHOD: This project was designed based on a philosophy known as Train-the-trainers which train proficient colposcopists and a cadre of local trainers who can continue to train and maintain their expertise in a self-sustaining system. The Train-the-trainers workshop is a 1-day program that focuses on three domains; knowledge, communication, and practical skills. Trainer candidates were given pre-course reading assignments and presentation decks. The expert trainers provided feedback on their presentations and tips on communication skills. The practical aspects of the training are supported by proficiency at the Loop Electro-excision procedure simulator and their responses to frequently asked questions. RESULTS: Sixteen physicians from Vietnam attended the Colposcopy Workshop in 2018 and are used as controls. Eleven attended a workshop conducted by trainer candidates who went through the training program outlined above in 2019. A Wilcoxon Signed-ranks test indicated that differences between pre- and post-quizzes' scores were statistically significant in both the 2018 (Z=4.21, P=0.003, r=1.26) and 2019 cohorts (Z=3.558, P<0.001, r=0.89) while Mann-Whitney U test did not detect the difference between the 2018 and 2019 cohorts, U=70.0, P=0.359, r=0.176. The subjective feedback scores from Year 2019 were similar to scores to Year 2018. CONCLUSION: Our preliminary data did not highlight any differences between lectures delivered by expert trainers and lectures delivered by trainer candidates trained in the program. Train-the- trainers might be a more sustainable model for organically raising expertise to effectively provide cervical cancer screening and prevention in low-to-middle-income countries.

The Effects of a Functional Three-dimensional (3D) Printed Knee Joint Simulator in Improving Anatomical Spatial Knowledge.

In recent decades, three-dimensional (3D) printing as an emerging technology, has been utilized for imparting human anatomy knowledge. However, most 3D printed models are rigid anatomical replicas that are unable to represent dynamic spatial relationships between different anatomical structures. In this study, the data obtained from a computed tomography (CT) scan of a normal knee joint were used to design and fabricate a functional knee joint simulator for anatomical education. Utility of the 3D printed simulator was evaluated in comparison with traditional didactic learning in first-year medical students (n = 35), so as to understand how the functional 3D simulator could assist in their learning of human anatomy. The outcome measure was a quiz comprising 11 multiple choice questions based on locking and unlocking of the knee joint. Students in the simulation group (mean score = 85.03%, ±SD 10.13%) performed significantly better than those in the didactic learning group, P < 0.05 (mean score = 70.71%, ±SD 15.13%), which was substantiated by large effect size, as shown by a Cohen's d value of 1.14. In terms of learning outcome, female students who used 3D printed simulators as learning aids achieved greater improvement in their quiz scores as compared to male students in the same group. However, after correcting for the modality of instruction, the sex of the students did not have a significant influence on the learning outcome. This randomized study has demonstrated that the 3D printed simulator is beneficial for anatomical education and can help in enriching students' learning experience.

Virtual breast oncoplastic surgery simulator (VBOSS): A novel training tool in breast surgery.

Virtual simulators have been employed for the teaching of breast surgery. However, there remains no virtual simulator for the training of oncoplastic breast conserving surgery. This is the first known report of virtual simulator for oncoplastic breast conserving surgery training, to the best of our knowledge.

Comparison between fixed-dose, intracoronary bolus-only versus standard weight-adjusted dose, intravenous bolus and infusion administration of abciximab in patients undergoing primary percutaneous coronary intervention.

We studied the safety and effectiveness of fixed-dose, intracoronary bolus-only abciximab in 195 patients who underwent primary percutaneous coronary intervention for ST-segment elevation myocardial infarction. The patients were divided into 2 groups: Group A (n=120, 61.5%) received fixed-dose, intracoronary bolus-only, abciximab 10 mg; and Group B (n=75, 38.5%) received standard intravenous bolus (0.25 mg/kg) and maintenance abciximab infusion of 0.125 µg/kg/min for 12 h. There was no statistically significant difference in the baseline and post-procedure TIMI flow between Groups A and B. Final TIMI 3 flow was achieved in 90.0% and 89.3% of the patients in Groups A and B, respectively (p=0.14). Final TIMI myocardial perfusion grade 2/3 was achieved in 92.5% and 96.0% of the patients in Groups A and B, respectively (p=0.45). The six-month clinical outcomes were similar between Groups A and B (8.3% versus 5.3%, p=0.62).