Needle-like Multifunctional Biphasic Microfiber for Minimally Invasive Implantable Bioelectronics.

Implantable bioelectronics has attracted significant attention in electroceuticals and clinical medicine for precise diagnosis and efficient treatment of target diseases. However, conventional rigid implantable devices face challenges such as poor tissue-device interface and unavoidable tissue damage during surgical implantation. Despite continuous efforts to utilize various soft materials to address such issues, their practical applications remain limited. Here, we report a needle-like stretchable microfiber composed of a phase-convertible liquid metal (LM) core and a multifunctional nanocomposite shell for minimally invasive soft bioelectronics. The sharp tapered microfiber can be stiffened by freezing akin to a conventional needle to penetrate soft tissue with minimal incision. Once implanted in vivo where the LM melts, unlike conventional stiff needles, it regains soft mechanical properties, which facilitate a seamless tissue-device interface. The nanocomposite incorporating with functional nanomaterials exhibits both low impedance and the ability to detect physiological pH, providing biosensing and stimulation capabilities. The fluidic liquid metal embedded in the nanocomposite shell enables high stretchability and strain-insensitive electrical properties. This multifunctional biphasic microfiber conforms to the surfaces of the stomach, muscle, and heart, offering a promising approach for electrophysiological recording, pH sensing, electrical stimulation, and radiofrequency ablation in vivo. This article is protected by copyright. All rights reserved.

Next-Generation Cardiac Interfacing Technologies Using Nanomaterial-Based Soft Bioelectronics.

Cardiac interfacing devices are essential components for the management of cardiovascular diseases, particularly in terms of electrophysiological monitoring and implementation of therapies. However, conventional cardiac devices are typically composed of rigid and bulky materials and thus pose significant challenges for effective long-term interfacing with the curvilinear surface of a dynamically beating heart. In this regard, the recent development of intrinsically soft bioelectronic devices using nanocomposites, which are fabricated by blending conductive nanofillers in polymeric and elastomeric matrices, has shown great promise. The intrinsically soft bioelectronics not only endure the dynamic beating motion of the heart and maintain stable performance but also enable conformal, reliable, and large-area interfacing with the target cardiac tissue, allowing for high-quality electrophysiological mapping, feedback electrical stimulations, and even mechanical assistance. Here, we explore next-generation cardiac interfacing strategies based on soft bioelectronic devices that utilize elastic conductive nanocomposites. We first discuss the conventional cardiac devices used to manage cardiovascular diseases and explain their undesired limitations. Then, we introduce intrinsically soft polymeric materials and mechanical restraint devices utilizing soft polymeric materials. After the discussion of the fabrication and functionalization of conductive nanomaterials, the introduction of intrinsically soft bioelectronics using nanocomposites and their application to cardiac monitoring and feedback therapy follow. Finally, comments on the future prospects of soft bioelectronics for cardiac interfacing technologies are discussed.

The future of valvular heart disease assessment and therapy.

Valvular heart disease (VHD) is becoming more prevalent in an ageing population, leading to challenges in diagnosis and management. This two-part Series offers a comprehensive review of changing concepts in VHD, covering diagnosis, intervention timing, novel management strategies, and the current state of research. The first paper highlights the remarkable progress made in imaging and transcatheter techniques, effectively addressing the treatment paradox wherein populations at the highest risk of VHD often receive the least treatment. These advances have attracted the attention of clinicians, researchers, engineers, device manufacturers, and investors, leading to the exploration and proposal of treatment approaches grounded in pathophysiology and multidisciplinary strategies for VHD management. This Series paper focuses on innovations involving computational, pharmacological, and bioengineering approaches that are transforming the diagnosis and management of patients with VHD. Artificial intelligence and digital methods are enhancing screening, diagnosis, and planning procedures, and the integration of imaging and clinical data is improving the classification of VHD severity. The emergence of artificial intelligence techniques, including so-called digital twins-eg, computer-generated replicas of the heart-is aiding the development of new strategies for enhanced risk stratification, prognostication, and individualised therapeutic targeting. Various new molecular targets and novel pharmacological strategies are being developed, including multiomics-ie, analytical methods used to integrate complex biological big data to find novel pathways to halt the progression of VHD. In addition, efforts have been undertaken to engineer heart valve tissue and provide a living valve conduit capable of growth and biological integration. Overall, these advances emphasise the importance of early detection, personalised management, and cutting-edge interventions to optimise outcomes amid the evolving landscape of VHD. Although several challenges must be overcome, these breakthroughs represent opportunities to advance patient-centred investigations.

Performance of 2020 AHA/ACC HCM Guidelines and Incremental Value of Myocardial Strain for Predicting SCD.

Background: The 2020 American Heart Association (AHA)/American College of Cardiology (ACC) guidelines for sudden cardiac death (SCD) risk stratification in hypertrophic cardiomyopathy (HCM) need further international validation. Objectives: Performance of the guidelines and the incremental value of myocardial strain for predicting SCD in HCM were investigated. Methods: In 1,416 HCM patients, SCD risk was stratified according to the 2020 AHA/ACC and 2014 European Society of Cardiology (ESC) guidelines. Left ventricular (LV) global longitudinal strain (GLS) and left atrial reservoir strain (LARS) were measured. The main outcome consisted of SCD events. Results: Overall, 29.1% had major risk factors (RFs), and 14.7% had nonmajor RFs in the absence of major RFs; estimated 5-year SCD event rates were 6.8% and 2.3%, respectively. SCD risk was significantly increased in the former group but not in the latter. When stratified by the number of RFs, 5-year SCD event rates were 1.9%, 3.0%, 4.9%, and 18.4% for patients with 0, 1, 2, and 3 or more RFs, respectively. SCD risk was elevated in patients with multiple RFs but not in those with a single RF. Performance of the AHA/ACC and ESC guidelines did not differ significantly over 10 years (5-year time-dependent area under the curve: 0.677 vs 0.724; P = 0.235). Decreased LV GLS and LARS were independently associated with SCD events with optimal cutoffs of LV GLS <13% and LARS <21%. Adding LV GLS and LARS to the guidelines had incremental predictive value. Conclusions: The 2020 AHA/ACC guidelines were predictive of SCD events with modest power in a large Asian HCM cohort. Implantable cardioverter-defibrillators are reasonable in patients with multiple RFs, and consideration of myocardial strain can improve SCD prediction.

Irreversible myocardial injury attenuates the benefits of sacubitril/valsartan in heart failure patients.

BACKGROUND: Despite the established benefits of angiotensin receptor-neprilysin inhibitor (ARNI) in heart failure with reduced ejection fraction (HFrEF) across various etiologies, there are controversies regarding the effects of ARNI in patients with irreversible myocardial injury. The aim of this study is to investigate the impact of irreversible myocardial injury on the benefits of ARNI treatment in patients with HFrEF, consisted of both ischemic and non-ischemic etiologies. METHODS AND RESULTS: We conducted a retrospective single-center study including 409 consecutive patients with HFrEF treated with ARNI between March 2017 and May 2020. Irreversible myocardial injury was defined as nonviable myocardium without contractile reserve, which suggests a limited potential for recovery of left ventricular function and geometry. At baseline, irreversible myocardial injury was observed in 129 (31.5%) patients. Composite outcome was cardiovascular death or hospitalization for heart failure, which occurred in 56 (43.4%) and 61 (21.8%) patients with and without irreversible myocardial injury, respectively. On multivariable analysis, irreversible injury presence, but not ischemic etiology, was an independent predictor of composite outcome (hazard ratio 2.16, 95% confidence interval 1.33-3.49). Mediation analysis revealed that the increased risk of the composite outcome due to irreversible myocardial injury was mediated by attenuated LV reverse remodeling (Z value = 2.02, P = 0.043). CONCLUSIONS: The presence of irreversible myocardial injury was significantly associated with the response to ARNI treatment in patients with HFrEF, regardless of etiology.

Batteryless implantable device with built-in mechanical clock for automated and precisely timed drug administration.

Adherence to medication plays a crucial role in the effective management of chronic diseases. However, patients often miss their scheduled drug administrations, resulting in suboptimal disease control. Therefore, we propose an implantable device enabled with automated and precisely timed drug administration. Our device incorporates a built-in mechanical clock movement to utilize a clockwork mechanism, i.e., a periodic turn of the hour axis, enabling automatic drug infusion at precise 12-h intervals. The actuation principle relies on the sophisticated design of the device, where the rotational movement of the hour axis is converted into potential mechanical energy and is abruptly released at the exact moment for drug administration. The clock movement can be charged either automatically by mechanical agitations or manually by winding the crown, while the device remains implanted, thereby enabling the device to be used permanently without the need for batteries. When tested using metoprolol, an antihypertensive drug, in a spontaneously hypertensive animal model, the implanted device can deliver drug automatically at precise 12-h intervals without the need for further attention, leading to similarly effective blood pressure control and ultimately, prevention of ventricular hypertrophy as compared with scheduled drug administrations. These findings suggest that our device is a promising alternative to conventional methods for complex drug administration.

Quantitative metrics of the LV trabeculated layer by cardiac CT and cardiac MRI in patients with suspected noncompaction cardiomyopathy.

OBJECTIVES: To compare cardiac computed tomography (CCT) and cardiac magnetic resonance (CMR) for the quantitative assessment of the left ventricular (LV) trabeculated layer in patients with suspected noncompaction cardiomyopathy (NCCM). MATERIALS AND METHODS: Subjects with LV excessive trabeculation who underwent both CMR and CCT imaging as part of the prospective international multicenter NONCOMPACT clinical study were included. For each subject, short-axis CCT and CMR slices were matched. Four quantitative metrics were estimated: 1D noncompacted-to-compacted ratio (NCC), trabecular-to-myocardial area ratio (TMA), trabecular-to-endocardial cavity area ratio (TCA), and trabecular-to-myocardial volume ratio (TMV). In 20 subjects, end-diastolic and mid-diastolic CCT images were compared for the quantification of the trabeculated layer. Relationships between the metrics were investigated using linear regression models and Bland-Altman analyses. RESULTS: Forty-eight subjects (49.9 ± 12.8 years; 28 female) were included in this study. NCC was moderately correlated (r = 0.62), TMA and TMV were strongly correlated (r = 0.78 and 0.78), and TCA had excellent correlation (r = 0.92) between CMR and CCT, with an underestimation bias from CCT of 0.3 units, and 5.1, 4.8, and 5.4 percent-points for the 4 metrics, respectively. TMA, TCA, and TMV had excellent correlations (r = 0.93, 0.96, 0.94) and low biases (- 3.8, 0.8, - 3.8 percent-points) between the end-diastolic and mid-diastolic CCT images. CONCLUSIONS: TMA, TCA, and TMV metrics of the LV trabeculated layer in patients with suspected NCCM demonstrated high concordance between CCT and CMR images. TMA and TCA were highly reproducible and demonstrated minimal differences between mid-diastolic and end-diastolic CCT images. CLINICAL RELEVANCE STATEMENT: The results indicate similarity of CCT to CMR for quantifying the LV trabeculated layer, and the small differences in quantification between end-diastole and mid-diastole demonstrate the potential for quantifying the LV trabeculated layer from clinically performed coronary CT angiograms. KEY POINTS: • Data on cardiac CT for quantifying the left ventricular trabeculated layer are limited. • Cardiac CT yielded highly reproducible metrics of the left ventricular trabeculated layer that correlated well with metrics defined by cardiac MR. • Cardiac CT appears to be equivalent to cardiac MR for the quantification of the left ventricular trabeculated layer.

Thalidomide and a Dipeptidyl Peptidase 4 Inhibitor in a Rat Model of Experimental Autoimmune Myocarditis.

BACKGROUND AND OBJECTIVES: Myocarditis is a potentially fatal disease, but curative treatments have not yet been established. Myocardial inflammation is an important pathogenesis of this disease, and immunosuppressants such as methylprednisolone and immunoglobulin have been used for treatment; however, the effectiveness needs to be improved. Thalidomide and dipeptidyl peptidase (DPP) 4 inhibitors were recently investigated regarding their immunomodulatory properties. This study aimed to test whether thalidomide or a DPP4 inhibitor (evogliptin) can improve the effectiveness of myocarditis treatment using a rat model of experimental autoimmune myocarditis (EAM). METHODS: Rats with or without myocarditis were administered thalidomide at 100 mg/kg/day and DPP4 inhibitor at 10 mg/kg/day orally. Measurement of echocardiography, serum inflammatory cytokines, myocardial histopathological examination, and immunohistochemical staining for leukocytes, macrophages, CD4+ T cells, and cytoskeleton were performed after 3 weeks, and the fibrosis area was measured after 3 and 6 weeks. RESULTS: Thalidomide and DPP4 inhibitor did not reduce the severity of myocarditis compared with the EAM without treatment rats by comparing the echocardiographic data, myocardial CD4+, macrophages, neutrophil infiltrations, and the heart weight/body weight ratio in 3 weeks. The levels of inflammatory cytokines were not lower in the thalidomide and DPP4 inhibitor-treated group than in the untreated group in 3 weeks. In 6 weeks, thalidomide and DPP4 inhibitors did not reduce the fibrosis area compared to untreated groups. CONCLUSIONS: Although thalidomide and the DPP4 inhibitor had an immunomodulatory effect and are used against inflammatory diseases, they did not ameliorate myocardial inflammation and fibrosis in this rat model of EAM.

Ceph-Net: automatic detection of cephalometric landmarks on scanned lateral cephalograms from children and adolescents using an attention-based stacked regression network.

BACKGROUND: The success of cephalometric analysis depends on the accurate detection of cephalometric landmarks on scanned lateral cephalograms. However, manual cephalometric analysis is time-consuming and can cause inter- and intra-observer variability. The purpose of this study was to automatically detect cephalometric landmarks on scanned lateral cephalograms with low contrast and resolution using an attention-based stacked regression network (Ceph-Net). METHODS: The main body of Ceph-Net compromised stacked fully convolutional networks (FCN) which progressively refined the detection of cephalometric landmarks on each FCN. By embedding dual attention and multi-path convolution modules in Ceph-Net, the network learned local and global context and semantic relationships between cephalometric landmarks. Additionally, the intermediate deep supervision in each FCN further boosted the training stability and the detection performance of cephalometric landmarks. RESULTS: Ceph-Net showed a superior detection performance in mean radial error and successful detection rate, including accuracy improvements in cephalometric landmark detection located in low-contrast soft tissues compared with other detection networks. Moreover, Ceph-Net presented superior detection performance on the test dataset split by age from 8 to 16 years old. CONCLUSIONS: Ceph-Net demonstrated an automatic and superior detection of cephalometric landmarks by successfully learning local and global context and semantic relationships between cephalometric landmarks in scanned lateral cephalograms with low contrast and resolutions.

Prognostic and Safety Implications of Renin-Angiotensin-Aldosterone System Inhibitors in Hypertrophic Cardiomyopathy: A Real-World Observation Over 2,000 Patients.

BACKGROUND AND OBJECTIVES: The prognostic or safety implication of renin-angiotensin-aldosterone system inhibitors (RASi) in hypertrophic cardiomyopathy (HCM) are not well established, mainly due to concerns regarding left ventricular outflow tract (LVOT) obstruction aggravation. We investigated the implications of RASi in a sizable number of HCM patients. METHODS: We enrolled 2,104 consecutive patients diagnosed with HCM in 2 tertiary university hospitals and followed up for five years. RASi use was defined as the administration of RASi after diagnostic confirmation of HCM. The primary and secondary outcomes were all-cause mortality and hospitalization for heart failure (HHF). RESULTS: RASi were prescribed to 762 patients (36.2%). During a median follow-up of 48.1 months, 112 patients (5.3%) died, and 94 patients (4.5%) experienced HHF. Patients using RASi had less favorable baseline characteristics than those not using RASi, such as older age, more frequent history of comorbidities, and lower ejection fraction. Nonetheless, there was no difference in clinical outcomes between patients with and without RASi use (log-rank p=0.368 for all-cause mortality and log-rank p=0.443 for HHF). In multivariable analysis, patients taking RASi showed a comparable risk of all-cause mortality (hazard ratio [HR], 0.70, 95% confidence interval [CI], 0.43-1.14, p=0.150) and HHF (HR, 1.03, 95% CI, 0.63-1.70, p=0.900). In the subgroup analysis, there was no significant interaction of RASi use between subgroups stratified by LVOT obstruction, left ventricular (LV) ejection fraction, or maximal LV wall thickness. CONCLUSIONS: RASi use was not associated with worse clinical outcomes. It might be safely administered in patients with HCM if clinically indicated.

Left ventricular global longitudinal strain as a prognosticator in hypertrophic cardiomyopathy with a low-normal left ventricular ejection fraction.

AIMS: The aim of this study was to investigate the prognostic utility of left ventricular (LV) global longitudinal strain (LV-GLS) in patients with hypertrophic cardiomyopathy (HCM) and an LV ejection fraction (LVEF) of 50-60%. METHODS AND RESULTS: This retrospective cohort study included 349 patients with HCM and an LVEF of 50-60%. The primary outcome was a composite of cardiovascular death, including sudden cardiac death (SCD) and SCD-equivalent events. The secondary outcomes were SCD/SCD-equivalent events, cardiovascular death (including SCD), and all-cause death. The final analysis included 349 patients (mean age 59.2 ± 14.2 years, men 75.6%). During a median follow-up of 4.1 years, the primary outcome occurred in 26 (7.4%), while the secondary outcomes of SCD/SCD-equivalent events, cardiovascular death, and all-cause death occurred in 15 (4.2%), 20 (5.7%), and 34 (9.7%), respectively. After adjusting for age, atrial fibrillation, ischaemic stroke, LVEF, and left atrial volume index, absolute LV-GLS (%) was independently associated with the primary outcome [adjusted hazard ratio (HR) 0.88, 95% confidence interval (CI) 0.788-0.988, P = 0.029]. According to receiver operating characteristic analysis, 10.5% is an optimal cut-off value for absolute LV-GLS in predicting the primary outcome. Patients with an absolute LV-GLS ≤ 10.5% had a higher risk of the primary outcome than those with an absolute LV-GLS > 10.5% (adjusted HR 2.54, 95% CI 1.117-5.787, P = 0.026). Absolute LV-GLS ≤ 10.5% was an independent predictor for each secondary outcome (P < 0.05). CONCLUSIONS: LV-GLS was an independent predictor of a composite of cardiovascular death, including SCD/SCD-equivalent events, in patients with HCM and an LVEF of 50-60%. Therefore, LV-GLS can help in risk stratification in these patients.

Endocardial versus whole-myocardial tracking global longitudinal strain analysis in patients with hypertrophic cardiomyopathy: A preliminary comparative study.

BACKGROUND AND OBJECTIVES: We investigated whether the feasibility of left ventricular (LV) global longitudinal strain (GLS) in hypertrophic cardiomyopathy (HCM) varies according to the methodology (e.g. endocardial vs. whole myocardial tracking techniques). METHODS: We retrospectively analyzed 111 consecutive patients with HCM (median age, 58 years; male, 68.5%) who underwent both transthoracic echocardiography (TTE) and cardiac magnetic resonance imaging (apical 29.7%, septal 33.3%, and diffuse or mixed 37.0%). TTE-whole myocardial and TTE-endocardial GLS were measured and compared in terms of association with late gadolinium enhancement (LGE) extent and discrimination performance for extensive LGE (>15% of the LV myocardium). RESULTS: Although TTE-whole myocardial and TTE-endocardial GLS were significantly correlated, absolute TTE-endocardial GLS values (19.3 [16.2-21.9] %) were higher than TTE-whole myocardial GLS values (13.3[10.9-15.6] %, p<0.001). Both TTE-derived GLS parameters were significantly correlated with the LGE extent and independently associated with extensive LGE (odds ratio [OR] 1.30, p = 0.022; and OR 1.24, p = 0.013, respectively). Discrimination performance for extensive LGE was comparable between TTE-whole myocardial and TTE-endocardial GLS (area under the curve [AUC], 0.747 and 0.754, respectively, pdifference = 0.610). However, among patients with higher LV mass index (>70 g/m2), only TTE-whole myocardial GLS correlated with LGE extent and was independently associated with extensive LGE (OR 1.35, p = 0.042), while TTE-endocardial GLS did not. Additionally, TTE-whole myocardial GLS had better discrimination performance for extensive LGE than TTE-endocardial GLS (AUC, 0.705 and 0.668, respectively, pdifference = 0.006). CONCLUSION: TTE-derived GLS using either the endocardial or whole myocardial tracking technique is feasible in patients with HCM. However, in those with severe hypertrophy, TTE-whole myocardial GLS is better than TTE-endocardial GLS.

Association between office visit intervals and long-term cardiovascular risk in hypertensive patients.

Hypertension is a chronic disease that requires long-term follow-up in many patients, however, optimal visit intervals are not well-established. This study aimed to evaluate the incidences of major cardiovascular events (MACEs) according to visit intervals. We analyzed data from 9894 hypertensive patients in the Korean Hypertension Cohort, which enrolled and followed up 11,043 patients for over 10 years. Participants were classified into five groups based on their median visit intervals (MVIs) during the 4-year period and MACEs were compared among the groups. The patients were divided into clinically relevant MVIs of one (1013; 10%), two (1299; 13%), three (2732; 28%), four (2355; 24%), and six months (2515; 25%). The median follow-up period was 5 years (range: 1745 ± 293 days). The longer visit interval groups did not have an increased cumulative incidence of MACE (12.9%, 11.8%, 6.7%, 5.9%, and 4%, respectively). In the Cox proportional hazards model, those in the longer MVI group had a smaller hazard ratio (HR) for MACEs or all-cause death: 1.77 (95% confidence interval [CI], 1.45-2.17), 1.7 (95% CI: 1.41-2.05), 0.90 (95% CI: 0.74-1.09) and 0.64 (95% CI: 0.52-0.79), respectively (Reference MVI group of 75-104 days). In conclusion, a follow-up visits with a longer interval of 3-6 months was not associated with an increased risk of MACE or all-cause death in hypertensive patients. Therefore, once medication adjustment is stabilized, a longer interval of 3-6 months is reasonable, reducing medical expenses without increasing the risk of cardiovascular outcomes.

Smoking behavior change and risk of cardiovascular disease incidence and mortality in patients with type 2 diabetes mellitus.

BACKGROUND: We aimed to examine the association between smoking behavior change and risk of cardiovascular disease (CVD) incidence and mortality in patients with type 2 diabetes mellitus (T2DM). METHODS: This study used nationwide data from the Korean National Health Insurance System and included 349,137 T2DM patients who smoked. Smoking behavior changes were defined with five groups: quitters, reducers I (≥ 50% reduction), reducers II (20-50% reduction), sustainers (± 20%), and increasers (≥ 20% increase) from the number of cigarettes/day at the baseline. RESULTS: During a median follow-up of 5.1 years, 6,514 cases of myocardial infarction (MI) (1.9%), 7,837 cases of ischemic stroke (IS) (2.2%), and 14,932 deaths (4.3%) were identified. Quitters had a significantly decreased risk of MI (adjusted hazard ratio [aHR] 0.80, 95% CI 0.75-0.86) and IS (aHR 0.80, 95% CI 0.75-0.85) compared to sustainers, whereas reducers did not have a significant association with the risk of MI (aHR 1.03, 95% CI 0.94-1.13) and IS (aHR 1.00, 95% CI 0.92-1.08) in reducer I. Quitters also had a lower all-cause and CVD mortality than sustainers. CONCLUSIONS: Smoking cessation was associated with decreased CVD incidence, and all-cause and CVD mortality among T2DM patients. However, smoking reduction was not associated with decreased risks for these.

Machine learning reveals sex-specific associations between cardiovascular risk factors and incident atherosclerotic cardiovascular disease.

We aimed to investigate sex-specific associations between cardiovascular risk factors and atherosclerotic cardiovascular disease (ASCVD) risk using machine learning. We studied 258,279 individuals (132,505 [51.3%] men and 125,774 [48.7%] women) without documented ASCVD who underwent national health screening. A random forest model was developed using 16 variables to predict the 10-year ASCVD in each sex. The association between cardiovascular risk factors and 10-year ASCVD probabilities was examined using partial dependency plots. During the 10-year follow-up, 12,319 (4.8%) individuals developed ASCVD, with a higher incidence in men than in women (5.3% vs. 4.2%, P < 0.001). The performance of the random forest model was similar to that of the pooled cohort equations (area under the receiver operating characteristic curve, men: 0.733 vs. 0.727; women: 0.769 vs. 0.762). Age and body mass index were the two most important predictors in the random forest model for both sexes. In partial dependency plots, advanced age and increased waist circumference were more strongly associated with higher probabilities of ASCVD in women. In contrast, ASCVD probabilities increased more steeply with higher total cholesterol and low-density lipoprotein (LDL) cholesterol levels in men. These sex-specific associations were verified in the conventional Cox analyses. In conclusion, there were significant sex differences in the association between cardiovascular risk factors and ASCVD events. While higher total cholesterol or LDL cholesterol levels were more strongly associated with the risk of ASCVD in men, older age and increased waist circumference were more strongly associated with the risk of ASCVD in women.

Data-driven mortality risk prediction of severe degenerative mitral regurgitation patients undergoing mitral valve surgery.

AIMS: The outcomes of mitral valve replacement/repair (MVR) in severe degenerative mitral regurgitation (MR) patients depend on various risk factors. We aimed to develop a risk prediction model for post-MVR mortality in severe degenerative MR patients using machine learning. METHODS AND RESULTS: Consecutive severe degenerative MR patients undergoing MVR were analysed (n = 1521; 70% training/30% test sets). A random survival forest (RSF) model was constructed, with 3-year post-MVR all-cause mortality as the outcome. Partial dependency plots were used to define the thresholds of each risk factor. A simple scoring system (MVR-score) was developed to stratify post-MVR mortality risk. At 3 years following MVR, 90 patients (5.9%) died in the entire cohort (59 and 31 deaths in the training and test sets). The most important predictors of mortality in order of importance were age, haemoglobin, valve replacement, glomerular filtration rate, left atrial dimension, and left ventricular (LV) end-systolic diameter. The final RSF model with these six variables demonstrated high predictive performance in the test set (3-year C-index 0.880, 95% confidence interval 0.834-0.925), with mortality risk increased strongly with left atrial dimension >55 mm, and LV end-systolic diameter >45 mm. MVR-score demonstrated effective risk stratification and had significantly higher predictability compared to the modified Mitral Regurgitation International Database score (3-year C-index 0.803 vs. 0.750, P = 0.034). CONCLUSION: A data-driven machine learning model provided accurate post-MVR mortality prediction in severe degenerative MR patients. The outcome following MVR in severe degenerative MR patients is governed by both clinical and echocardiographic factors.

Stretchable Low-Impedance Conductor with Ag-Au-Pt Core-Shell-Shell Nanowires and in Situ Formed Pt Nanoparticles for Wearable and Implantable Device.

Mechanically soft metallic nanocomposites have gained much attention as a key material for intrinsically stretchable biointegrated devices. However, it has been challenging to develop a stretchable conductive nanocomposite with all the desired material characteristics including high conductivity, high stretchability, low cytotoxicity, and low impedance. Here, we present a material strategy for the stretchable conductive nanocomposite, particularly emphasizing low impedance, by combining silver-gold-platinum core-shell-shell nanowires and homogeneously dispersed in situ synthesized platinum nanoparticles (Pt NPs). The highly embossed structure of the outermost Pt shell, together with the intrinsic electrical property of Pt, contributes to minimizing the impedance. The gold-platinum double-layer sheath prevents leaching of cytotoxic Ag ions, thus improving biocompatibility. Homogeneously dispersed Pt NPs, synthesized in situ during fabrication of the nanocomposite, simultaneously enhance conductivity, reduce impedance, and improve stretchability by supporting the percolation network formation. This intrinsically stretchable nanocomposite conductor can be applied to wearable and implantable bioelectronics for recording biosignals and delivering electrical stimulations in vivo.

Ventricular tachyarrhythmia treatment and prevention by subthreshold stimulation with stretchable epicardial multichannel electrode array.

The implantable cardioverter-defibrillator (ICD) is an effective method to prevent sudden cardiac death in high-risk patients. However, the transvenous lead is incompatible with large-area electrophysiological mapping and cannot accommodate selective multichannel precision stimulations. Moreover, it involves high-energy shocks, resulting in pain, myocardial damage, and recurrences of ventricular tachyarrhythmia (VTA). We present a method for VTA treatment based on subthreshold electrical stimulations using a stretchable epicardial multichannel electrode array, which does not disturb the normal contraction or electrical propagation of the ventricle. In rabbit models with myocardial infarction, the infarction was detected by mapping intracardiac electrograms with the stretchable epicardial multichannel electrode array. Then, VTAs could be terminated by sequential electrical stimuli from the epicardial multichannel electrode array beginning with low-energy subthreshold stimulations. Last, we used these subthreshold stimulations to prevent the occurrence of additional VTAs. The proposed protocol using the stretchable epicardial multichannel electrode array provides opportunities toward the development of innovative methods for painless ICD therapy.