Predictors and Incidence of Health Status Deterioration in Patients with Early Atrial Fibrillation.

BACKGROUND: Various treatment approaches for atrial fibrillation (AF) have demonstrated improved health status, yet the significance of these therapeutic interventions in individual patients remains unclear. OBJECTIVE: This study aimed to evaluate health status changes in patients with early AF, focusing on those who experience clinically significant deterioration following treatment initiation. METHODS: We analyzed data from a multicenter, prospective registry of newly diagnosed patients with AF. One-year changes in health status across different treatment strategies were assessed using the Atrial Fibrillation Effect on QualiTy-of-life Overall Summary (AFEQT-OS) score. Clinically relevant deterioration and improvement in health status were defined as ≥5-point decrease and increase in AFEQT-OS score, respectively; no change was -5 to 5 points. RESULTS: Overall, 1,960 patients with AF were evaluated. Mean AFEQT-OS score at baseline and 1-year follow-up were 76.7±17.7 and 85.4±14.8, respectively. Although most patients (53.9%) experienced clinically important improvement, a considerable proportion had no change (28.7%) or deterioration (17.4%) in their health status. Proportions of patients with no change or deterioration varied by treatment strategy: 59.9, 53.9, and 32.0% in rate control, antiarrhythmic drug, and catheter ablation groups, respectively. Multivariable model identified older age, female sex, heart failure, coronary artery disease, and higher baseline AFEQT-OS score as independent predictors of worsening health status, regardless of treatment strategy. CONCLUSION: Many patients with early AF experience worsening or no change in health status irrespective of treatment strategy. Standardizing patients' health status assessment, especially for patients with comorbidities may aid in patients' selection and their outcomes.

Establishment and application of a new 4/6 infarct nephrectomy rat model for moderate chronic kidney disease.

PURPOSE: To develop a new 4/6 infarct nephrectomy (INx) model rat mimicking moderate chronic kidney disease (CKD) and to evaluate its application. METHODS: We modified the conventional 5/6 INx rat model to create the 4/6 INx model by ligating the renal artery branch to induce infarction of one-third of the left kidney after right kidney removal and compared biochemically and histologically both models. To demonstrate the application of the 4/6 INx model, the effects of a supplementary compound containing calcium carbonate, chitosan, palm shell activated charcoal etc., that is effective for both CKD and its complications, were compared between both models. RESULTS: Impairment of renal function in the 4/6 INx group was significantly more moderate than in the 5/6 INx group (P < 0.05). The 4/6 INx group showed less histological damage in kidney than in the 5/6 INx group. The supplementary compound did not improve CKD in the 5/6 INx group, but ameliorated elevation of blood urea nitrogen in the 4/6 INx group. CONCLUSIONS: We developed the 4/6 INx model, which is more moderate than the conventional 5/6 INx model. This model could potentially demonstrate the effectiveness of drugs and supplements intended to prevent CKD and its progression.

Injury prevalence and associated factors among Japanese lacrosse collegiate athletes.

Context: Sports injuries have a substantial impact on athletes' performance and health. To reduce the risk of an injury occurring, the prevalence, localization, and severity need to be established. Objective: To examine the prevalence of sports injuries in collegiate lacrosse athletes. Design: Descriptive epidemiological study using online survey design. Setting: Japanese universities associated with UNIVAS. Participants: A total of 1,689 Japanese collegiate lacrosse athletes, 978 females and 701 males. Main outcome measures: Athletes were surveyed on the injuries within the previous year, their severity, localization, and onset characteristics. The support of an athletic trainer and its association with the odds of sustaining an injury was assessed. Factors related to injuries were explored. Results: One-year prevalence of injuries was 42%. Male sex, higher year at the university, and support from an athletic trainer were identified as factors related to higher odds of sustaining an injury and practicing at least 5 days per week was associated with lower odds of sustaining an injury. Conclusions: Male sex athletes, and athletes at the higher year at university are especially at risk of sustaining a lacrosse injury. The aspects of training (e.g., frequency, volume) should be investigated across the athlete development process to address these findings. Further investigation is needed to determine the extent to which the support of athletic trainers affects both the frequency and severity of injuries in lacrosse athletes.

Artificial intelligence-enabled prediction of chemotherapy-induced cardiotoxicity from baseline electrocardiograms.

Anthracyclines can cause cancer therapy-related cardiac dysfunction (CTRCD) that adversely affects prognosis. Despite guideline recommendations, only half of the patients undergo surveillance echocardiograms. An AI model detecting reduced left ventricular ejection fraction from 12-lead electrocardiograms (ECG) (AI-EF model) suggests ECG features reflect left ventricular pathophysiology. We hypothesized that AI could predict CTRCD from baseline ECG, leveraging the AI-EF model's insights, and developed the AI-CTRCD model using transfer learning on the AI-EF model. In 1011 anthracycline-treated patients, 8.7% experienced CTRCD. High AI-CTRCD scores indicated elevated CTRCD risk (hazard ratio (HR), 2.66; 95% CI 1.73-4.10; log-rank p < 0.001). This remained consistent after adjusting for risk factors (adjusted HR, 2.57; 95% CI 1.62-4.10; p < 0.001). AI-CTRCD score enhanced prediction beyond known factors (time-dependent AUC for 2 years: 0.78 with AI-CTRCD score vs. 0.74 without; p = 0.005). In conclusion, the AI model robustly stratified CTRCD risk from baseline ECG.

Local alternating heat and cold stimulation affects hemodynamics and oxygenation in fatigued muscle tissue and autonomic nervous activity: a single-arm interventional study.

BACKGROUND: Local alternating heat and cold stimulation as an alternative to contrast bath may cause intermittent vasoconstriction and vasodilation, inducing a vascular pumping effect and consequently promoting increased tissue blood flow and oxygenation. This study aimed to examine the effects of local alternating heat and cold stimulation, using a wearable thermal device, on the hemodynamics of fatigued muscle tissue and autonomic nervous activity. METHODS: Twenty healthy individuals experienced fatigue in the periarticular muscles of the shoulder joint due to a typing task. Local alternating heat and cold stimulations were then applied to the upper trapezius muscle. Muscle hardness was measured using a muscle hardness meter, and muscle tissue hemodynamics and oxygenation were evaluated using near-infrared spectroscopy before and after the stimulation. Autonomic nervous activity was also evaluated using heart rate variability. RESULTS: Alternating heat and cold stimulation decreased muscle hardness of the fatigued trapezius muscle from 1.38 ± 0.15 to 1.31 ± 0.14 N (P < 0.01). The concentration of total hemoglobin in the trapezius muscle tissue increased from - 0.21 ± 1.36 to 2.29 ± 3.42 µmol/l (P < 0.01), and the tissue hemoglobin oxygen saturation also increased from 70.1 ± 5.4 to 71.1 ± 6.0% (P < 0.05). Additionally, the heart rate variability parameter, which is an index of sympathetic nervous activity, increased from 3.82 ± 2.96 to 6.86 ± 3.49 (P < 0.01). A correlation was found between increased tissue hemoglobin oxygen saturation and increased parameters of sympathetic nervous activity (r = 0.50, P < 0.05). CONCLUSIONS: Local alternating heat and cold stimulation affected the hemodynamic response in fatigued muscle tissue and autonomic nervous activity. This stimulation is more efficient than conventional contrast baths in terms of mobility and temperature control and has potential as a new versatile therapeutic intervention for muscle fatigue. TRIAL REGISTRATION: UMIN-CTR (UMIN000040087: registered on April 7, 2020, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000045710 . UMIN000040620: registered on June 1, 2020, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000046359 ).

Visually assessing work performance using a smartwatch via day-to-day fluctuations in heart rate variability.

Objective: To optimize workplace health promotion, a simple method for quantifying allostatic load response is needed. This study examines the feasibility of optimizing objective anxiety and presenteeism monitoring using daily smartwatch-measured ultra-short heart rate variability (HRV). Methods: Office workers without diagnosed disease prospectively performed 30 s HRV self-measurement each morning for two months and responded to the State-Trait Anxiety Inventory (STAI) and Work Limitation Questionnaire (WLQ). Logistic regression analysis examined daily HRV parameters in the high-trait anxiety group (HTA, STAI ≥ 40) using mean and variance HRV, age, self-reported gender, and body mass index (BMI). The ideal cutoff value enabled comparison of WLQ using the Mann-Whitney U test. Heart rate variability data were collected for 279 participants (male ratio, 83.9%; age, 42 ± 10 years) who completed questionnaires and monitored HRV for 30+ days. Results: Compared to the low-trait anxiety group, HTA exhibited higher variance of the log-transformed coefficient of component variance of high-frequency component (LnccvHF) and low-frequency per HF (Lnccv L/H), in addition to differences in the means of these HRV parameters. In addition to BMI (odds ratio [OR] = 0.92, p = 0.02) and mean LnccvL/H (OR = 10.75, p < 0.01), the variance of Lnccv L/H was an independent predictor of HTA (OR = 2.39E + 8, p = 0.011). The daily Lnccv L/H dispersion group had a lower WLQ productivity loss score (p = 0.02, r = 0.17). Conclusions: By focusing on HRV dispersion status, this simple and instantly applicable daily HRV monitoring system enables optimized quantitative monitoring of anxiety and productivity.

Assessment of patient characteristics influencing the complexity of leadless pacemaker implantation.

Background: The complexity of leadless pacemaker (LP) implantation varies widely. However, the predictive factors determining this difficulty are poorly understood. Objective: The purpose of this study was to evaluate the factors influencing LP implantation difficulty, specifically procedural time during right atrial (RA) and right ventricular (RV) manipulation, based on patient background, cardiac function, and anatomic characteristics. Methods: Analysis included LP implantation cases between 2017 and 2023, excluding the initial 3 implants performed by each operator. The relevance of patient background, cardiac function, and anatomic features on procedural and fluoroscopy times was evaluated. Results: Fifty-four patients (mean age 82.2 ± 10.0 years; 57.4% male) were included in the study. Median procedural and fluoroscopy time was 45.8 minutes and 16.0 minutes, respectively, with an average of 2.0 ± 1.4 device deployments. Univariate analysis showed associations between procedural time and older age, RA and RV diameter, and severity of tricuspid regurgitation (TR). After adjustment for physician and potential contributing factors, RV dilation (midventricular diameter ≥35 mm) and severe TR were identified as independent predictors of prolonged procedural time. Medical history exhibited no association with procedural time. Consistent results were observed in analyses using fluoroscopy time as the outcome. Conclusion: RV dilation and severe TR were associated with prolonged procedural time for LP implantation. Anatomic features obtained from preprocedural echocardiography could provide valuable insights into both the safety and efficiency of LP implantation, thereby enhancing tailored treatment strategies for patients undergoing pacemaker implantation.

Physician Estimates and Patient-Reported Health Status in Atrial Fibrillation.

Importance: A primary objective in managing atrial fibrillation (AF) is to optimize patients' health status, which can be done only if physicians accurately quantify the outcomes associated with AF in patients' lives. Objective: To explore physicians' estimation of the health status of patients with AF and its association with subsequent care and outcomes. Design, Setting, and Participants: A multicenter, prospective cohort study was conducted in 2 outpatient practices in Tokyo, Japan. Participants included patients with newly diagnosed AF or those referred for initial treatment of AF at outpatient practices and treating physicians from November 8, 2018, to April 1, 2020. Data analysis was performed from December 22, 2022, to July 7, 2023. Exposures: Participating patients completed the Atrial Fibrillation Effect on Quality-of-Life (AFEQT) questionnaire, a 20-item tool covering 4 domains with a 7-point Likert scale; 3 domains (symptoms, daily activities, and treatment concerns) were used in this study. Blinded to patients' responses, treating physicians answered a 3-item questionnaire quantifying each patient's AFEQT domain with a single item. Patients' mean Likert scale responses within each AFEQT domain were subtracted from the physicians' assessments so that higher scores (≥0.5 points) indicate physician underestimation, while lower scores (≤0.5 points) indicate physician overestimation of the health status of patients with AF. Main Outcomes and Measures: The independent association of physician-patient concordance with treatment escalation (alteration or initiation of antiarrhythmic drugs, cardioversion, or catheter ablation) and 1-year adjusted changes in AFEQT scores. Results: Among 330 patients (238 [72.1%] men; mean [SD] age, 67.9 [11.9] years; 163 [49.4%] with paroxysmal AF), physicians correctly estimated health status in 112 patients (33.9%), underestimated it in 42 patients (12.7%), and overestimated it in 176 patients (53.3%). Treatment escalation occurred in 63.6% of patients whose health status was correctly estimated, 47.6% of those whose health status was underestimated, and 66.3% of patients whose health status was overestimated. After multivariable adjustment, underestimation of health status was independently associated with less treatment escalation (adjusted odds ratio, 0.43; 95% CI, 0.20-0.90) and less frequent AFEQT overall summary score improvement at 1 year (underestimated, 2.5 [95% CI, -1.6 to 6.7] vs correctly and overestimated health status, 8.4 [95% CI, 7.0-9.9] points; P = .01). Conclusions and Relevance: In this cohort study, physician underestimation of the health status of patients with AF was common and associated with less aggressive treatment and less health status improvement at 1 year.

Clinical Utility of Baseline Brain Natriuretic Peptide Levels on Health Status Outcomes after Catheter Ablation for Atrial Fibrillation in Individuals without Heart Failure.

BACKGROUND: Catheter ablation (CA) benefits atrial fibrillation (AF) patients with heart failure (HF). Brain natriuretic peptide (BNP), a marker of left-ventricular pressure load, may serve as a potential surrogate for predicting quality of life (QOL) in a broader range of patients. METHODS: Within the multicenter KiCS-AF registry, 491 AF patients underwent CA without clinical HF (e.g., documented history of HF, left ventricular ejection fraction ≤ 40%, or BNP levels ≥ 100 pg/mL). Participants, aged 61 ± 10 years, were categorized by baseline BNP quartiles. Atrial Fibrillation Effect on QualiTy-of-Life (AFEQT) questionnaire assessments were assessed at baseline and 1 year. RESULTS: A lower baseline BNP correlated with reduced AFEQT scores. Post CA, all groups showed significant AFEQT score improvements. The lower-BNP group displayed notable enhancements (18.2 ± 1.2, 15.0 ± 1.1, 12.6 ± 1.2, 13.6 ± 1.2, p < 0.005), especially in symptom and treatment concern areas. Even those with normal BNP levels (≤18.4 pg/mL) exhibited significant QOL improvements. Comparing paroxysmal AF (PAF) and non-PAF groups, the PAF group, especially with higher BNP levels, showed greater AFEQT score improvements. CONCLUSIONS: This study establishes BNP as a predictive marker for QOL enhancement in non-HF patients undergoing CA for AF. BNP levels represent AF stages, with individuals in earlier stages, especially within normal BNP levels, experiencing greater QOL improvements.

Discontinuation of Oral Anticoagulants in Atrial Fibrillation Patients: Impact of Treatment Strategy and on Patients' Health Status.

AIMS: The discontinuation of oral anticoagulants (OACs) remains as a significant concern in the management of atrial fibrillation (AF). The discontinuation rate may vary depending on management strategy, and physicians may also discontinue OACs due to concerns about patient satisfaction with their care. We aimed to assess the incidence of OAC discontinuation and its relationship to patients' health in an outpatient AF registry. METHODS AND RESULTS: From a multicenter registry for newly recognized AF patients (n = 3313), we extracted 1647 (49.7%) patients with OACs and a CHA2DS2-Vasc score of ≥2. Discontinuation was defined as sustained cessation of OACs within a 1-year follow-up. We examined predictors associated with discontinuation and its relations to health status defined by the AFEQT questionnaire. Of the 1647 patients, 385 (23.6%) discontinued OACs after 1 year, with discontinuation rates varying across treatment strategies (15.3% for catheter ablation, 4.9% for rhythm control with antiarrhythmic drugs, and 3.0% for rate control). Successful rhythm control was associated with discontinuation in the catheter ablation (OR 6.61, 95% CI 3.00-14.6, p < 0.001) and antiarrhythmic drugs (OR 6.47, 95% CI 2.62-15.9, p < 0.001) groups, whereas the incidence of bleeding events within 1 year was associated with discontinuation in the rate control group. One-year AFEQT scores did not significantly differ between patients who discontinued OACs and those who did not in each treatment strategy group. CONCLUSIONS: OAC discontinuation was common among AF patients with significant stroke risk but varied depending on the chosen treatment strategy. This study also found no significant association between OAC discontinuation and patients' health status.

Anaerobic threshold using sweat lactate sensor under hypoxia.

We aimed to investigate the reliability and validity of sweat lactate threshold (sLT) measurement based on the real-time monitoring of the transition in sweat lactate levels (sLA) under hypoxic exercise. In this cross-sectional study, 20 healthy participants who underwent exercise tests using respiratory gas analysis under hypoxia (fraction of inspired oxygen [FiO2], 15.4 ± 0.8%) in addition to normoxia (FiO2, 20.9%) were included; we simultaneously monitored sLA transition using a wearable lactate sensor. The initial significant elevation in sLA over the baseline was defined as sLT. Under hypoxia, real-time dynamic changes in sLA were successfully visualized, including a rapid, continual rise until volitionary exhaustion and a progressive reduction in the recovery phase. High intra- and inter-evaluator reliability was demonstrated for sLT's repeat determinations (0.782 [0.607-0.898] and 0.933 [0.841-0.973]) as intraclass correlation coefficients [95% confidence interval]. sLT correlated with ventilatory threshold (VT) (r = 0.70, p < 0.01). A strong agreement was found in the Bland-Altman plot (mean difference/mean average time: - 15.5/550.8 s) under hypoxia. Our wearable device enabled continuous and real-time lactate assessment in sweat under hypoxic conditions in healthy participants with high reliability and validity, providing additional information to detect anaerobic thresholds in hypoxic conditions.

MRP1-Dependent Extracellular Release of Glutathione Induces Cardiomyocyte Ferroptosis After Ischemia-Reperfusion.

BACKGROUND: The membrane components of cardiomyocytes are rich in polyunsaturated fatty acids, which are easily oxidized. Thus, an efficient glutathione-based lipid redox system is essential for maintaining cellular functions. However, the relationship between disruption of the redox system during ischemia-reperfusion (IR), oxidized lipid production, and consequent cell death (ferroptosis) remains unclear. We investigated the mechanisms underlying the disruption of the glutathione-mediated reduction system related to ferroptosis during IR and developed intervention strategies to suppress ferroptosis. METHODS: In vivo fluctuations of both intra- and extracellular metabolite levels during IR were explored via microdialysis and tissue metabolome analysis. Oxidized phosphatidylcholines were assessed using liquid chromatography high-resolution mass spectrometry. The areas at risk following IR were assessed using triphenyl-tetrazolium chloride/Evans blue stain. RESULTS: Metabolomic analysis combined with microdialysis revealed a significant release of glutathione from the ischemic region into extracellular spaces during ischemia and after reperfusion. The release of glutathione into extracellular spaces and a concomitant decrease in intracellular glutathione concentrations were also observed during anoxia-reperfusion in an in vitro cardiomyocyte model. This extracellular glutathione release was prevented by chemical inhibition or genetic suppression of glutathione transporters, mainly MRP1 (multidrug resistance protein 1). Treatment with MRP1 inhibitor reduced the intracellular reactive oxygen species levels and lipid peroxidation, thereby inhibiting cell death. Subsequent in vivo evaluation of endogenously oxidized phospholipids following IR demonstrated the involvement of ferroptosis, as levels of multiple oxidized phosphatidylcholines were significantly elevated in the ischemic region 12 hours after reperfusion. Inhibition of the MRP1 transporter also alleviated intracellular glutathione depletion in vivo and significantly reduced the generation of oxidized phosphatidylcholines. Administration of MRP1 inhibitors significantly attenuated infarct size after IR injury. CONCLUSIONS: Glutathione was released continuously during IR, primarily in an MRP1-dependent manner, and induced ferroptosis. Suppression of glutathione release attenuated ferroptosis and reduced myocardial infarct size following IR.

Prognostic Implications and Efficacy of Catheter Ablation by Atrial Fibrillation Type.

Background Catheter ablation (CA) for atrial fibrillation (AF) is preferred for paroxysmal AF (PAF) but selectively performed in patients with persistent AF (PersAF). This study aimed to investigate the prognostic differences and consequences of CA based on the AF type. Methods and Results Data from a multicenter AF cohort study were analyzed, categorizing patients as PAF or PersAF according to AF duration (≤7 or >7 days, respectively). A composite of all-cause death, heart failure hospitalization, stroke, and bleeding events during 2-year follow-up and changes in the Atrial Fibrillation Effect on Quality-of-life score were compared. Additionally, propensity score matching was performed to compare clinical outcomes of patients with and without CA in both AF types. Among 2788 patients, 51.6% and 48.4% had PAF and PersAF, respectively. Patients with PersAF had a higher incidence of the composite outcome (12.8% versus 7.2%; P<0.001) and smaller improvements in Atrial Fibrillation Effect on Quality-of-life scores than those with PAF. After adjusting for baseline characteristics, PersAF was an independent predictor of adverse outcomes (adjusted hazard ratio, 1.35 [95% CI, 1.30-1.78], P=0.031) and was associated with poor improvements in Atrial Fibrillation Effect on Quality-of-life scores. Propensity score matching analysis showed that the CA group had significantly fewer adverse events than the medication group among patients with PAF (odds ratio, 0.31 [95% CI, 0.18-0.68]; P=0.002). Patients with PersAF showed a similar but nonsignificant trend. Conclusions PersAF is a risk factor for worse clinical outcomes, including patients' health status. CA is associated with fewer adverse events, although careful consideration is required based on the AF type.

Patient concern regarding bleeding side effects from oral anticoagulation therapy for atrial fibrillation: An analysis from the multicenter KiCS-AF registry.

AIMS: The purpose of this study is to utilize PROs to determine the percentage of patients concerned about mild to moderate bleeding side effects of anticoagulants. METHODS AND RESULTS: We consecutively enrolled 3,312 newly diagnosed or referred patients for atrial fibrillation (AF) management from 11 sites within the Keio interhospital Cardiovascular Studies-Atrial Fibrillation Registry between September 2012 and May 2018. Of these patients, 2,636 (79.5%) were taking oral anticoagulants at enrollment. Using the Atrial Fibrillation Effect on Quality-of-life questionnaire (AFEQT), the patients who responded "1: not at all bothered" or "2: hardly bothered" on the seven-point scale regarding bleeding side effects were classified as the "no OAC concern" group while those responding "3: a little bothered" to "7: extremely bothered" were classified as the "OAC concern" group. On baseline analysis, 29.3% (n = 772) were "concerned" about bleeding side effects. The proportion of women and patients with AF-related symptoms was higher in the OAC concern vs. no OAC concern group (36.9% vs. 29.8%, p < 0.0004 and 66.2% vs. 56.7%, p < 0.0001, respectively). The CHADS2 scores ≥ 2 were comparable between groups. Of the 430 patients in the 1-year follow-up analysis, the proportion of the continued OAC concern group (1 year from enrollment) was 41.6%.The dabigatran, rivaroxaban, and apixaban usage rates were comparable between the two groups in baseline and 1-year follow-up analysis. CONCLUSION: Approximately one-third of all patients with AF on anticoagulant therapy were concerned regarding bleeding from short-and long-term anticoagulant use.

Deep learning-based model detects atrial septal defects from electrocardiography: a cross-sectional multicenter hospital-based study.

Background: Atrial septal defect (ASD) increases the risk of adverse cardiovascular outcomes. Despite the potential for risk mitigation through minimally invasive percutaneous closure, ASD remains underdiagnosed due to subtle symptoms and examination findings. To bridge this diagnostic gap, we propose a novel screening strategy aimed at early detection and enhanced diagnosis through the implementation of a convolutional neural network (CNN) to identify ASD from 12-lead electrocardiography (ECG). Methods: ECGs were collected from patients with at least one recorded echocardiogram at 3 hospitals from 2 continents (Keio University Hospital from July 2011 to December 2020, Brigham and Women's Hospital from January 2015 to December 2020, and Dokkyo Medical University Saitama Medical Center from January 2010 and December 2021). ECGs from patients with a diagnosis of ASD were labeled as positive cases while the remainder were labeled as negative. ECGs after the closure of ASD were excluded. After randomly splitting the ECGs into 3 datasets (50% derivation, 20% validation, and 30% test) with no patient overlap, a CNN-based model was trained using the derivation datasets from 2 hospitals and was tested on held-out datasets along with an external validation on the 3rd hospital. All eligible ECGs were used for derivation and validation whereas the earliest ECG for each patient was used for the test and external validation. The discrimination of ASD was assessed by the area under the receiver operating characteristic curve (AUROC). Multiple subgroups were examined to identify any heterogeneity. Findings: A total of 671,201 ECGs from 80,947 patients were collected from the 3 institutions. The AUROC for detecting ASD was 0.85-0.90 across the 3 hospitals. The subgroup analysis showed excellent performance across various characteristics Screening simulation using the model greatly increased sensitivity from 80.6% to 93.7% at specificity 33.6% when compared to using overt ECG abnormalities. Interpretation: A CNN-based model using 12-lead ECG successfully identified the presence of ASD with excellent generalizability across institutions from 2 separate continents. Funding: This work was supported by research grants from JST (JPMJPF2101), JSR corporation, Taiju Life Social Welfare Foundation, Kondou Kinen Medical Foundation, Research fund of Mitsukoshi health and welfare foundation, Tokai University School of Medicine Project Research and Internal Medicine Project Research, Secom Science and Technology Foundation, and Grants from AMED (JP23hma922012 and JP23ym0126813). This work was partially supported by One Brave Idea, co-funded by the American Heart Association and Verily with significant support from AstraZeneca and pillar support from Quest Diagnostics.

Real-Time Estimation of Anaerobic Threshold during Exercise Using Electrocardiogram in Heart Failure Patients.

Exercise therapy at the aerobic level is highly recommended to improve clinical outcomes in patients with heart failure, in which cardiopulmonary exercise testing (CPX) is required to determine anaerobic thresholds (ATs) but is not available everywhere. This study aimed to validate a method to estimate the AT using heart rate variability (HRV) analysis from electrocardiography data in patients with heart failure. Between 2014 and 2019, 67 patients with symptomatic heart failure underwent CPXs in a single university hospital. During the CPX, RR intervals was measured continuously and the HRV threshold (HRVT), defined as the inflection point of <5 ms2 of a high-frequency component (HFC) using the power spectrum analysis, was determined. Patients were divided into two groups according to the mean HFC at rest (high-HFC group, n = 34 and low-HFC group, n = 33). The high-HFC group showed good correlation between the VO2 at AT and HRVT (r = 0.63, p < 0.001) and strong agreement (mean difference, -0.38 mL/kg, p = 0.571). The low-HFC group also showed modest correlation (r = 0.41, p = 0.017) but poor agreement (mean differences, 3.75 mL/kg, p < 0.001). In conclusion, the HRVT obtained from electrocardiography may be a useful indicator for estimating AT in patients with heart failure.

Delineation of conduction gaps of linear lesions during atrial fibrillation ablation using ultra-high-density mapping.

AIMS: Linear lesions are routinely created by radiofrequency catheter ablation. Unwanted electrical conduction gaps can be produced and are often difficult to ablate. This study aimed to clarify the characteristics of conduction gaps during atrial fibrillation ablation by analysing bidirectional activation maps using a high-density mapping system (RHYTHMIA). METHODS AND RESULTS: This retrospective study included 31 patients who had conduction gaps along pulmonary vein (PV) isolation or box ablation lesions. Activation maps were sequentially created during pacing from the coronary sinus and PV to reveal the earliest activation site, defined by the entrance and exit. The locations, length between the entrance and exit (gap length), and direction were analysed. Thirty-four bidirectional activation maps were drawn: 21 were box isolation lesions (box group), and 13 were PV isolation lesions (PVI group). Among the box group, nine conduction gaps were present in the roof region and 12 in the bottom region, while nine in right PV and four in left PV among the PVI group. Gap lengths in the roof region were longer than those in the bottom region (26.8 ± 11.8 vs. 14.5 ± 9.8 mm; P = 0.022), while those in right PV tended to longer than those in left PV (28.0 ± 15.3 vs. 16.8 ± 8.0 mm, P = 0.201). CONCLUSION: The entrances and exits of electrical conduction gaps were separated, especially in the roof region, indicating that epicardial conduction might contribute to gap formation. Identifying the bidirectional conduction gap might indicate the location and direction of epicardial conduction.

Baseline Health Status and its Association With Subsequent Cardiovascular Events in Patients With Atrial Fibrillation.

BACKGROUND: Clinical practice guidelines recommend optimizing the health status of patients with atrial fibrillation (AF) as a primary treatment goal. Whether disease-specific health status is associated with subsequent clinical events is unknown. OBJECTIVES: The aim of this study was to investigate the association between health status and subsequent clinical events among patients with AF. METHODS: Using a prospective cohort study of patients with new-onset AF referred to 11 hospitals (n = 3,313, 68.4% men, mean age 67.8 ± 11.6 years), data were extracted from 3,296 patients (99.4%) who completed the disease-specific Atrial Fibrillation Effects on Quality-of-Life (AFEQT) questionnaire between 2012 and 2018. Factors associated with baseline AFEQT overall summary (OS) score and associations between major adverse cardiovascular or neurologic events (MACNE; a composite of all-cause death, stroke, or new-onset heart failure hospitalization) over 2 years were investigated. RESULTS: Overall, 517 participants (15.6%) had poor to fair health status (AFEQT OS <60), and 1,035 (31.2%) had fair to good health status (AFEQT OS 60 to <80) at baseline. Female sex, younger age, family history of AF, higher baseline heart rate, paroxysmal AF, initial visit to the emergency department, and history of heart failure were associated with lower AFEQT OS scores. Of those, 226 participants (6.8%) experienced MACNE; restricted cubic spline analysis with adjustment for factors associated with baseline AFEQT score showed a nonlinear increase in the risk for MACNE with AFEQT OS score <80. The strongest associations were observed for baseline AFEQT daily activity scores (for AFEQT daily activity score of <80 vs ≥80, HR: 1.65; 95% CI: 1.21-2.25). CONCLUSIONS: Diminished health status in patients with AF is common and is independently associated with subsequent adverse cardiovascular events.

Estimation of maximal lactate steady state using the sweat lactate sensor.

A simple, non-invasive algorithm for maximal lactate steady state (MLSS) assessment has not been developed. We examined whether MLSS can be estimated from the sweat lactate threshold (sLT) using a novel sweat lactate sensor for healthy adults, with consideration of their exercise habits. Fifteen adults representing diverse fitness levels were recruited. Participants with/without exercise habits were defined as trained/untrained, respectively. Constant-load testing for 30 min at 110%, 115%, 120%, and 125% of sLT intensity was performed to determine MLSS. The tissue oxygenation index (TOI) of the thigh was also monitored. MLSS was not fully estimated from sLT, with 110%, 115%, 120%, and 125% of sLT in one, four, three, and seven participants, respectively. The MLSS based on sLT was higher in the trained group as compared to the untrained group. A total of 80% of trained participants had an MLSS of 120% or higher, while 75% of untrained participants had an MLSS of 115% or lower based on sLT. Furthermore, compared to untrained participants, trained participants continued constant-load exercise even if their TOI decreased below the resting baseline (P < 0.01). MLSS was successfully estimated using sLT, with 120% or more in trained participants and 115% or less in untrained participants. This suggests that trained individuals can continue exercising despite decreases in oxygen saturation in lower extremity skeletal muscles.