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PURPOSE Despite decreased prevalence of tuberculosis, the incidence of the diseases associated with nontuberculous mycobacteria (NTM) has been increasing in South Korea and around the world. The present retrospective study was conducted to determine longitudinal changes in the epidemiology and distribution of NTM over 13 years at a tertiary care hospital in Korea. MATERIALS AND METHODS We retrospectively analyzed data on Mycobacterium species over 13 years (January 2007 to December 2019) by utilizing the laboratory information system. Mycobacterium species were identified using biochemical tests and PCR-restriction fragment length polymorphism and Mycobacteria GenoBlot assays. RESULTS After excluding duplicates from the initial pool of 17996 mycobacterial isolates, 7674 strains were analyzed and 2984 (38.9%) NTM were isolated. The proportion of NTM continuously increased over the 13-year period, from 17.0% in 2007 to 57.5% in 2019. Among the NTM isolates, the most common species were Mycobacterium intracellulare (50.6%), M. avium (18.3%), M. fortuitumcomplex (4.9%), M. abscessus (4.5%), M. gordonae (3.3%), M. kansasii (1.1%), M. chelonae (1.0%), and M. massiliense (0.9%). In patients over the age of 70 years, the proportion of NTM among the isolates increased from 26.6% in 2007 to 62.0% in 2019, and that of M. intracellulare isolates among the NTM increased from 13.9% (11/79) in 2007 to 37.4% (175/468) in 2019. CONCLUSION The number of NTM isolates continuously increased over the study period, and the increase in the proportion of M.intracellulare in patients aged over 70 years was notable.

We designed a highly sensitive reverse transcription nested polymerase chain reaction targeting the M-segment (NPCR-M) of severe fever with thrombocytopenia syndrome (SFTS) virus. NPCR-M was performed in parallel with three other referenced PCR assays QPCR-S, PCR-M, and NPCR-S to assess their clinical usefulness as routine diagnostic techniques for SFTS. In this multi-centered prospective study, 122 blood samples from 38 laboratory-confirmed SFTS patients and 85 control samples were used. The results demonstrated that QPCR-S and NPCR-S had better sensitivity rate up to 21 days after symptom onset however, the PCR-M showed poor sensitivity after 7 days of symptom onset. Our designed NPCR-M had a higher detection rate up to 40 days from symptom onset and revealed the persistence of SFTSV RNA in the early convalescent phase. No false-positive results were seen for the control samples. Additionally, NPCR-M showed positive results for a sample that initially showed negative results from other PCRs and for many other samples collected in the convalescent phase of SFTS. Our designed nested PCR is suitable for SFTSV detection in patients’ blood collected in the acute and early convalescent phase of SFTS, and shows better sensitivity and high specificity even up to 40 days after symptom onset.

Background A single‑lead implantable cardioverter-defibrillator (ICD) with a floating atrial dipole has been developed to enhance the diagnostic capability of atrial arrhythmias and to facilitate adjudication of arrhythmic events without the additional effort required for atrial lead insertion. However, there have been concerns about the long-term reliability of atrial sensing. Methods We enrolled patients with the single-chamber ICD with atrial-sensing electrodes from 4 tertiary university hospitals in Korea. Minimal, maximal, and mean P wave amplitudes were collected at 3–6 months, 6–12 months, and 12–24 months after implantation. The difference between the minimal and maximal sensing amplitudes was calculated as an indicator of the variability of atrial sensing, while the atrial sensing stability was assessed using the mean amplitude. Results A total of 86 patients were included for analysis. The variability of atrial sensing amplitudes significantly decreased at 12–24 months compared to 3–6 months (p = 0.01), while mean atrial amplitudes were stable throughout the mean follow-up duration of 17.4 months. Nine patients (10.5%) experienced inappropriate ICD therapy mostly due to misclassification of supraventricular tachycardia. Conclusions Under the hypothesis that sensing stability can be guaranteed as the variability decreases with time, we suggest that the concern about long-term sensing stability of a floating dipole can be abated with an ICD that has been implanted for over 2 years.

Background/Aims Atrial fibrillation (AF)-related stroke accounts for 20% of ischemic strokes. Rivaroxaban use in AF patients for preventing stroke and systemic embolism was approved in 2013 in Korea. This study was to investigate the safety and effectiveness of rivaroxaban use in Korean patients with non-valvular AF in a real-world setting. Methods This was an analysis of the Korean patients in Xarelto for Prevention of Stroke in Patients with Atrial Fibrillation in Asia-Pacific (XANAP), which was a prospective, observational cohort study including patients with non-valvular AF starting rivaroxaban treatment to prevent stroke or non-central nervous system systemic embolism (non-CNS SE), conducted in 10 Asian countries. Results A total of 844 patients were enrolled in the Korean portion of the XANAP study. In XANAP Korea, the mean age was 70.1 years and 62.6% were males. The mean CHADS2 score was 2.5 and the mean CHA2DS2-VASc score was 3.8. 47% of the patients had experienced prior stroke or non-CNS SE or transient ischemic attack. 73.6% of the patients had CHADS2 score ≥ 2. Incidence proportions of 0.8% of the patients (1.1 per 100 patient-years) developed adjudicated treatment-emergent major bleeding. Death was observed in 1.2% of the patients. The incidence of non-major bleeding as well as thromboembolic event were 8.4% (11.6 per 100 patient-years) and 1.5% (2.0 per 100 patient-years), respectively. Conclusions This study reaffirmed the consistent safety profile of rivaroxaban. We found consistent results with overall XANAP population for rivaroxaban in terms of safety in non-valvular AF patients for the prevention of stroke and non-CNS SE.

A misalignment of LiDAR as low as a few degrees could cause a significant error in obstacle detection and mapping that could cause safety and quality issues. In this paper, an accurate inspection system is proposed for estimating an automotive LiDAR alignment error after sensor attachment on a vehicle. The proposed method uses only a single target board at a close range to estimate the orientations and the horizontal position of the LiDAR attachment with sub-degree and millimeter level accuracy. It is a static method for the stationary target board and vehicle during the inspection. Also, it only requires one pose of the target board and does not utilize other sensors, such as a camera or GPS. The performance of the proposed method is evaluated using a test bench that can control the reference yaw and horizontal translation of LiDAR within ranges of 3 degrees and 30 millimeters, respectively. The experimental results for a low-resolution 16 channel LiDAR (Velodyne VLP-16) confirmed that misalignment could be estimated with accuracy within 0.2 degrees and 4 mm. The high accuracy and simplicity of the proposed system make it practical for large-scale industrial applications such as automobile manufacturing process that inspects the sensor attachment for the safety quality control.

Background Coronavirus disease 2019 (COVID-19) is associated with acute respiratory distress syndrome, and corticosteroids have been considered as possible therapeutic agents for this disease. However, there is limited literature on the appropriate timing of corticosteroid administration to obtain the best possible patient outcomes. Methods This was a retrospective cohort study including patients with severe COVID-19 who received corticosteroid treatment from March 2 to June 30, 2020 in seven tertiary hospitals in South Korea. We analyzed the patient demographics, characteristics, and clinical outcomes according to the timing of steroid use. Twenty-two patients with severe COVID-19 were enrolled, and they were all treated with corticosteroids. Results Of the 22 patients who received corticosteroids, 12 patients (55%) were treated within 10 days from diagnosis. There was no significant difference in the baseline characteristics. The initial PaO2/FiO2 ratio was 168.75. The overall case fatality rate was 25%. The mean time from diagnosis to steroid use was 4.08 days and the treatment duration was 14 days in the early use group, while those in the late use group were 12.80 days and 18.50 days, respectively. The PaO2/FiO2 ratio, C-reactive protein level, and cycle threshold value improved over time in both groups. In the early use group, the time from onset of symptoms to discharge (32.4 days vs. 60.0 days, P = 0.030), time from diagnosis to discharge (27.8 days vs. 57.4 days, P = 0.024), and hospital stay (26.0 days vs. 53.9 days, P = 0.033) were shortened. Conclusions Among patients with severe COVID-19, early use of corticosteroids showed favorable clinical outcomes which were related to a reduction in the length of hospital stay.

An isolated tibial component revision could be a treatment option for isolated tibial side loosening; however, few studies have proved its efficacy. This study aimed to compare the clinical and radiological outcomes between isolated (tibial component) and total (femoral and tibial component) revision total knee arthroplasty (TKA).Between January 2008 and February 2017, 31 patients underwent revision TKA for isolated tibial side loosening; 14 underwent an isolated tibial component revision (isolated group) and 17 underwent total (both femoral and tibial components) revision surgery (total group). The postoperative range of motion (ROM), Western Ontario and McMaster Universities osteoarthritis (WOMAC) index, Knee Society knee score (KSKS), Knee Society function score (KSFS), and mechanical axis (MA) were compared between the two groups. The intraoperative tourniquet time and amount of blood drainage were also compared.The mean follow-up durations in the isolated and total groups were 40.7 and 56.1 months, respectively. Both groups had similar postoperative ROM, WOMAC index, KSKS, KSFS, and MA; however, significantly shorter tourniquet time (105.2 vs. 154.6 min, P 0.001) and less blood drainage (417.2 vs. 968.1 ml, P 0.001) were noted in the isolated group than in the total group.Isolated tibial component revision TKA for tibial component loosening showed comparable clinical and radiological outcomes to those of total revision TKA. The advantages of the isolated tibial component revision surgery were short operation time and small blood loss.Level III, Retrospective comparative study.

Objective To evaluate the effectiveness and safety of totally thoracoscopic ablation (TTA) in patients with left ventricular (LV) dysfunction for treatment of atrial fibrillation (AF) refractory to antiarrhythmic drug (AAD) therapy. Methods Between January 2012 and December 2018, 31 patients underwent TTA with drug-refractory AF and preoperative left ventricular ejection fraction (LVEF), Video Abstract

Background and Purpose: Unlike clinical atrial fibrillation (AF), the significance of subclinical AF (SCAF) burden in patients with permanent pacemakers has not been fully evaluated. Methods: We investigated whether the SCAF burden was associated with increased risks of composite adverse outcomes, including progression to clinical AF, ischemic stroke, myocardial infarction, heart failure-related hospitalization, or cardiac death, in patients without previous AF. To quantify the 6-month SCAF burden, the total cumulative time spent in SCAF during every 6-month follow-up was summed. Results: During the median 5.2-year follow-up, 496 consecutive permanent pacemaker patients were classified into the no SCAF (no SCAF episode in any device analysis; n=152), low-burden SCAF (6-month SCAF P P P P P Conclusions: In permanent pacemaker patients without preexisting AF, the presence of high-burden SCAF was closely associated with increased risks of composite adverse outcomes, particularly progression to clinical AF and ischemic stroke. Therefore, prospective studies deserve to be performed on the optimal anticoagulation therapy for permanent pacemaker patients with both high-burden SCAF and high stroke risk.

It has been known that ventricular conduction delays play a key role in the cardiac resynchronization therapy (CRT) response of patients with advanced heart failure (HF). However, no study to our knowledge has yet evaluated the serial changes in conduction times measured between different electrodes of CRT devices. The Reduction or Extension of Conduction Time with Ventricular Electromechanical Remodeling (RECOVER) study (NCT04397224) was designed to investigate serial changes in interelectrode conduction times and to elucidate their prognostic value. We plan to enroll 100 patients implanted with CRT systems with endocardial quadripolar left ventricular leads. Patients will be scheduled for follow-up every 3 months over a period of 2 years, where they will undergo measurement of interelectrode conduction times to evaluate their serial changes. The primary outcome of the RECOVER study is the correlation between the degree of conduction time changes and the CRT response as defined by echocardiography. The time course and prognostic value of the serial changes in conduction times will be investigated as well. The RECOVER study is investigating whether serial changes in interelectrode conduction times can be useful parameters in predicting the CRT response or detecting worsening HF at an early stage.

Background Chest physiotherapy (CPT) is a non-pharmacological therapy to facilitate airway secretion removal. There have been concerns about potential electromagnetic interference (EMI) and lead integrity problems during the use of vibrating CPT devices in patients with cardiac implantable electronic devices (CIEDs). Hypothesis Two CPT devices can be used safely in patients with CIED. Methods Volunteer patients with CIED underwent device interrogation to check lead integrity and device function before and after application of CPT devices. Mechanical lung vibrator and high-frequency chest wall oscillation (HFCWO) vests were used while monitoring surface electrocardiograms and intra-cardiac electrograms. Results We prospectively enrolled 46 patients with CIEDs (25 pacemakers, 15 implantable cardioverter-defibrillators, and six cardiac resynchronization therapy-defibrillators). There was no noise detection or EMI during CPT in any patient. None of the patients showed clinically significant changes in lead integrity parameters. HFCWO inappropriately accelerated the pacing rate up to the maximal programmed value in five patients with pacemakers and two with cardiac resynchronization therapy-defibrillators. Conclusion CPT may be safely applied to patients with CIED without compromising lead integrity or device function, except for unwanted increase in pacing rate caused by misdetection of chest wall vibration as patients' activity while using HFCWO. Deactivation of the accelerometer-based activity sensor may be needed when HFCWO is planned for CPT.

Background In idiopathic outflow tract ventricular arrhythmias (OT‐VAs), identifying the site with the earliest activation time (EAT) using activation mapping is critical to eliminating the arrhythmogenic focus. However, the optimal EAT for predicting successful radiofrequency catheter ablation (RFCA) has not been established. Hypothesis To evaluate the association between EAT and successful RFCA in idiopathic OT‐VAs and to determine the optimal cut‐off value of EAT for successful ablation. Methods We retrospectively analyzed patients undergoing RFCA for idiopathic OT‐VAs at a single center from January 2015 to December 2019. Results Acute procedural success was achieved in 168 patients (87.0%). Among these patients, 158 patients (81.9%) were classified in the clinical success group according to the recurrence of clinical VAs during median (Q1, Q3) follow‐up (330 days [182, 808]). EAT was significantly earlier in the clinical success group compared with the recurrence (p = .006) and initial failure (p

Background Cryoballoon ablation is a commonly used approach to treat patients with atrial fibrillation (AF). Objectives Report on the safety and efficacy of cryoballoon ablation for the treatment of AF in the largest global cohort of cryoablated patients prospectively studied within a single registry. Methods The Cryo AF Global Registry is a prospective, multi‐center registry. Patients with paroxysmal AF (PAF) or persistent AF (PsAF) were treated with the cryoballoon catheter according to routine practices at 93 sites across 36 countries. Primary efficacy endpoints included freedom from AF and freedom from AF/atrial flutter (AFL)/atrial tachycardia (AT) ≥30 seconds. The primary safety endpoint was serious device‐ or procedure‐related adverse events over 12 month follow‐up. Results During this evaluation window, 2922 subjects completed an index cryoballoon procedure, and 1440 completed 12 month follow‐up. The cohort was 61 ± 12 years of age, 36.3% female, and 78.7% PAF. Serious device‐ and procedure‐related adverse event rates were 1.5% and 3.4%, respectively. Freedom from AF/AFL/AT after the 90 day blanking period was 86.4% (95% CI: 84.3%‐88.3%) in patients with PAF and 70.9% (95% CI: 64.6%‐76.4%) in patients with PsAF. Freedom from AF/AFL/AT in first‐line PAF and PsAF was 90.0% (95% CI: 86.4%‐92.7%) and 72.9% (95% CI: 58.6%‐83.0%) at 12 months, respectively. Conclusions The Cryo Global AF Registry is the largest evaluation to demonstrate cryoablation is an efficient, safe, and effective treatment for patients with AF worldwide. Cryoablation was commonly used to treat patients prior to an AAD failure and may facilitate earlier therapy for patients on the AF disease continuum., Cryoballoon ablation was an efficient, safe, and effective treatment for 2,922 patients with paroxysmal and persistent atrial fibrillation treated according to standard‐of‐care techniques at 93 unique sites in 36 countries around the world.

Injecting an electrical current into a nonmagnetic layer toward the in-plane direction can reverse the magnetization direction of an adjacent ferromagnetic layer in a nonmagnet/ferromagnet heterostructure via spin-orbit torque (SOT). One of the most critical issues for memory and logic device applications is to reduce the critical current to assure low energy consumption. Herein, we report both enhanced SOT efficiency and reduced SOT-induced switching current in perpendicularly magnetized W/CoFeB heterostructures, where ultrathin tungsten nitride (W–N) layers with various N-compositions and thicknesses are placed in between W and CoFeB layers. The composition of the W–N layers affects the microstructure and, therefore, the electrical properties. The measured SOT efficiency is 0.54, and the switching current reduces to approximately one-fifth of its original value in the 0.2-nm-thick W–N layer sample containing 42 at% N. Our results suggest interface engineering is a practical approach to reduce switching current.

Aims We sought to evaluate the effectiveness of cardiac resynchronization therapy (CRT) in far‐advanced heart failure (FA‐HF) patients with New York Heart Association (NYHA) class‐IV status and dependency on intravenous drugs (IVDs) and/or invasive supportive treatments (ISTs). Methods and results Among 305 patients who underwent CRT implantation between October 2005 to December 2019, we identified 17 FA‐HF patients with NYHA class‐IV status and dependency on IVDs (inotropes, diuretics, vasopressors, or vasodilators) and/or ISTs (extracorporeal membranous oxygenator or continuous renal replacement therapy). All patients (median age = 68.7 years, non‐ischaemic cardiomyopathy = 15) remained dependent on several IVDs (2.2 ± 1.3 per patient) and/or ISTs for 11.3 ± 7.8 days due to multiple tapering failure (4.3 ± 3.2 per patient) before CRT implantation. However, 14 (82%) patients were successfully weaned from IVDs/ISTs within 5.2 ± 5.3 days following CRT, and 12 (71%) stayed alive for more than 1 year free of ventricular assist device or heart transplantation with symptom improvement (≥1 NYHA class) and a reduced annual HF hospitalization rate (P = 0.002). Considerable improvements in ventricular systolic function (P = 0.004) and volumetric reverse remodelling (P = 0.007) were noticed during the long‐term follow‐up period (35 ± 15 months post‐CRT). The ventricular assist device/heart transplantation/death‐free survival rate post‐CRT was 71% and 65% at 1 and 3 years, respectively. Conclusions Cardiac resynchronization therapy implantation may be a feasible treatment that can offer short‐term and long‐term clinical benefits for NYHA class‐IV FA‐HF patients who are dependent on IVDs/ISTs. When considering treatment options, CRT should not be prematurely excluded solely based on a patient's dependency on IVDs/ISTs without first attempting to identify favourable CRT response factors.

Background: We investigated the impact of previous catheter ablation (CA) on the mid-term outcomes of totally thoracoscopic ablation in patients with lone atrial fibrillation (AF).Methods: Between February 2012 and July 2018, 332 patients underwent totally thora-coscopic ablation for the treatment of AF (persistent AF; n=264, 80%). The patients were stratified into CA (n=47, 14%) and non-CA (nCA; n=285, 86%) groups according to their CA history.Results: All the baseline clinical characteristics and risk factors were similar between the groups except for age, percentage of male patients, prevalence of paroxysmal AF, prior percutaneous coronary intervention, and left atrial volume index (LAVI). No significant in-tergroup differences were observed in the incidence of early and late complications. At late follow-up, normal sinus rhythm was observed in 92% (43 of 47) of the patients in the CA group and 85% (242 of 285) of the patients in the nCA group (p=0.268). The rate of free-dom from AF recurrence at 5 years was 55.3%±11.0% in the CA group, which was similar to that in the nCA group (55.7%±5.1%, p=0.690). In Cox regression analysis, preoperative brain natriuretic peptide levels and LAVI were associated with AF recurrence, but CA his-tory was not significant.Conclusion: Totally thoracoscopic ablation was safe and effective in treating AF irrespec-tive of CA history. A history of CA did not appear to affect the procedural complexity.

Endocardial radiofrequency catheter ablation is considered to be a useful procedure for paroxysmal atrial fibrillation. However, catheter ablation has difficulties in achieving successful results in patients with persistent or long-standing persistent atrial fibrillation. Currently, the gold standard is surgical ablation (the Cox maze III procedure). However, because surgical ablation requires a sternotomy and extracorporeal cardiopulmonary bypass and has been associated with surgery-related complications, minimally invasive (totally thoracoscopic) and epicardial-endocardial (hybrid) ablation procedures have been developed. This article reviews the primary surgical and hybrid approaches used to treat persistent or long-standing persistent atrial fibrillation.

Background After pandemic, A(H1N1)pdm09 is generally known to be associated with younger adults' infection and greater severity than seasonal A(H3N2) but some inconsistences between recent studies exist. Objectives We aimed to compare the epidemiology and clinical outcomes of A(H1N1)pdm09 and A(H3N2) to verify and consolidate about the knowledge of known differences of subtypes. Methods Data were retrospectively collected from the hospital‐based influenza morbidity and mortality surveillance in South Korea in nine tertiary care hospitals, from August 31, 2014, to August 25, 2018. Patients with H1N1pdm09 or H3N2 infection admitted in the emergency room or ward were recruited. Results A total of 1747 patients had influenza A and were divided into two groups those with A(H1N1)pdm09 (n = 240) and those with A(H3N2) (n = 1507). A(H1N1)pdm09 group had younger age (mean age ± standard deviation 50.0 ± 18.8 in H1N1 vs 53.4 ± 21.1 in H3N2, P = .030), lower influenza vaccination (27.9% vs 43.9%, P

BACKGROUND Despite many studies on new tools and strategies for cavotricuspid isthmus (CTI) ablation, there is an unmet need to improve the CTI ablation procedure. Recently, high-power short-duration (HPSD) ablation has been widely used for pulmonary vein (PV) isolation in atrial fibrillation. We evaluated the effectiveness and safety of HPSD for CTI ablation in atrial flutter (AFL). METHODS Eighty-four patients who underwent CTI ablation with or without simultaneous PV isolation between January 2018 and February 2019 were enrolled in this prospective cohort study. We compared procedural characteristics, periprocedural complications, and recurrence of atrial tachyarrhythmia (ATa) between the HPSD group (50 W for 15 s) and conventional group (30 W for 60 s). RESULTS A total of 84 patients were divided into the HPSD (n = 42) and conventional (n = 42) groups. Bidirectional CTI block was achieved in all patients and 95% achieved bidirectional block after the first-line ablation in both groups. Although there was no difference in the total number of ablation lines between the two groups (1.17 ± 0.7 vs 1.38 ± 0.8, P = .067), HPSD ablation significantly reduced total ablation time compared to the conventional group (236.0 ± 85.6 vs 534.2 ± 235.2 s, P

The growth arrest and DNA damage‐inducible beta (Gadd45β) protein have been associated with various cellular functions, but its role in progressive renal disease is currently unknown. Here, we examined the effect of Gadd45β deletion on cell proliferation and apoptosis, inflammation, and renal fibrosis in an early chronic kidney disease (CKD) mouse model following unilateral ureteral obstruction (UUO). Wild‐type (WT) and Gadd45β‐knockout (KO) mice underwent either a sham operation or UUO and the kidneys were sampled eight days later. A histological assay revealed that ablation of Gadd45β ameliorated UUO‐induced renal injury. Cell proliferation was higher in Gadd45β KO mouse kidneys, but apoptosis was similar in both genotypes after UUO. Expression of pro‐inflammatory cytokines after UUO was down‐regulated in the kidneys from Gadd45β KO mice, whereas UUO‐mediated immune cell infiltration remained unchanged. The expression of pro‐inflammatory cytokines in response to LPS stimulation decreased in bone marrow‐derived macrophages from Gadd45β KO mice compared with that in WT mice. Importantly, UUO‐induced renal fibrosis was ameliorated in Gadd45β KO mice unlike in WT mice. Gadd45β was involved in TGF‐β signalling pathway regulation in kidney fibroblasts. Our findings demonstrate that Gadd45β plays a crucial role in renal injury and may be a therapeutic target for the treatment of CKD.

Measuring the diffraction loss for high frequencies, long distances, and large diffraction angles is difficult because of the high path loss. Securing a well‐controlled environment to avoid reflected waves also makes long‐range diffraction measurements challenging. Thus, the prediction of diffraction loss at millimeter‐wave frequency bands relies on theoretical models, such as the knife‐edge diffraction (KED) and geometrical theory of diffraction (GTD) models; however, these models produce different diffraction losses even under the same environment. Our observations revealed that the KED model underestimated the diffraction loss in a large Fresnel‐Kirchhoff diffraction parameter environment. We collected power‐delay profiles when millimeter waves propagated over a building rooftop at millimeter‐wave frequency bands and calculated the diffraction losses from the measurements while eliminating the multipath effects. Comparisons between the measurements and the KED and GTD diffraction‐loss models are shown. Based on the measurements, an approximation model is also proposed that provides a simple method for calculating the diffraction loss using geometrical parameters.

Various surgical techniques, such as corticocancellous or cancellous bone graft and other vascularized bone grafting techniques have been developed to treat scaphoid nonunion. However, open grafting with dissection of wrist capsule and ligaments damages the joint and hence can lead to increased stiffness of the wrist and hand. Arthroscopic assisted bone grafting and percutaneous fixation have advantages such as minimal surgical trauma to the scaphoid blood supply and its ligament connection and provide a thorough wrist assessment, comprehensive approach for scaphoid nonunion and its sequelae in a minimally invasive manner. This article briefly discusses the characteristic anatomy of the wrist and scaphoid, and reviews the technique of arthroscopic bone grafting and percutaneous fixation for the treatment of scaphoid nonunion.

Background Frequent ventricular premature depolarizations (VPDs) can cause reversible cardiomyopathy (CMP). However, many patients maintain a normal left ventricular (LV) function with a high VPD burden. The electrocardiographic characteristics of VPD‐induced CMP have not been elucidated. Methods One hundred and eighty (91 men, age; 51 ± 15 years) patients with frequent idiopathic VPDs (>10% VPDs/day or >10 000 VPDs/day) were studied. All patients underwent successful ablation and were then divided into two groups according to the echocardiographic findings before and after the ablation procedure. Results Group A (n = 139) had a normal LV function with VPD frequencies, and Group B (n = 41) had reversible LV dysfunction after ablation. The VPD QRS duration (QRSd) was wider in patients with CMP (Group A vs Group B; 137.2 ± 12.0 milliseconds vs 159.7 ± 5.3 milliseconds, P, Figure 1 Eletrocardiographic parameters. A, CI and post‐VPD CI; B, QR and RS interval and amplitude; C, r/R transition interval; D, Initial and terminal Angle of VPD. Abbreviations: CI, coupling interval; SCL, sinus cycle length; VPD, ventricular premature depolarization

Purpose: We evaluated results of arthroscopically assisted volar and dorsal scapholunate(SL) ligament reconstruction using flexor carpi radialis(FCR). Methods: We reviewed 31 cases who had been operated from August 2015 to June 2018. Two cases were excluded and 4 cases lost contact. Twenty five wrists were included. The average follow-up duration was 25.3months. Diagnostic arthroscopy was performed to evaluate EWAS stage of SL instability and the reparability of SL ligament. The SL reconstruction was performed for the cases which showed EWAS stage IIIC, IV having gap over 3mm and irreparable SL ligament. The interval between the diagnosis and operation was 5.9 days in average. We modified the arthroscopic Corella technique by repairing the graft tendon to FCR. Results: All SL joints were stabilized to EWAS stage I arthroscopically after reconstruction. DASH score changed from 32.7 to 9.7. Grip power changed from 74.1% to 93.3%. Modified Mayo Wrist score was 83.8. Preoperative SL angle was 53.8。, postoperative 49.6。 and the last was 51.2。. The improvement between preoperative and last follow-up SL angle was statistically significant(p

Background Differences in the performance of suggested warfarin dosing algorithms among different ethnicities and genotypes have been reported; this necessitates the development of an algorithm with enhanced performance for specific population groups. Previous warfarin dosing algorithms underestimated warfarin doses in VKORC1 1173C carriers. We aimed to develop and validate a new warfarin dosing algorithm for Korean patients with VKORC1 1173C. Methods A total of 109 patients carrying VKORC1 1173CT (N=105) or 1173CC (N=4) were included in this study. Multiple regression analysis was performed to deduce a new dosing algorithm. Following literature searches for genotype-guided warfarin dosing algorithms, 21 algorithms were selected and evaluated using the correlation coefficient (ρ) of actual dose and estimated dose, mean error, and root mean square error. Results The developed algorithm is as follows: maintenance dose (mg/week)=exp [3.223-0.009×(age)+0.577×(body surface area [BSA])+0.178×(sex)-0.481×(CYP2C9 genotype)+0.227×(VKORC1 genotype)]. Integrated variables explained 44% of the variance in the maintenance dose. The predicted and actual doses showed moderate correlation (ρ=0.641) with the best performance with a mean error of -1.30 mg/week. The proportion of underestimated groups was 17%, which was lower than with the other algorithms. Conclusions This is the first study to develop and validate a warfarin dosing algorithm based on data from VKORC1 1173C carriers; it showed superior predictive performance compared with previously published algorithms.

Little information is available concerning the usefulness of electrophysiological confirmation followed by totally thoracoscopic ablation. This study aimed to examine whether postprocedural electrophysiological confirmation is always necessary after totally thoracoscopic ablation (TTA) in patients with isolated persistent atrial fibrillation. Forty-five patients with isolated persistent atrial fibrillation were randomized into 2 groups those who received routine electrophysiological confirmation and additional catheter ablation after totally thoracoscopic ablation (the hybrid group [n = 22]) and those who did not (the TTA group [n = 23]). Electrophysiological study was performed 4 or 5 days after surgery. No early or late mortality occurred. In the hybrid group, 5 patients (23%, 5/22) required additional ablation due to residual potential in the left atrium. At a year postoperatively, normal sinus rhythm was observed in 89% of patients (40/45) and similar in both groups (Odds ratio 0.80, 95% confidence interval 0.32 to 1.99). During follow-up, sinus rhythm was maintained in 16 patients (70%) in the TTA group without additional catheter ablation, which was similar (p = 0.920) to the results in the hybrid group (n = 15, 68.2%). Event-free survival rate at 12 months did not differ between groups (TTA group vs hybrid group, 78% vs 77%; p = 0.633). In simple Cox regression analysis, preoperative left atrium volume index was associated with atrial arrhythmia (p = 0.030, hazards ratio 1.087, 95% confidence interval 1.01-1.18). In conclusion, thoracoscopic ablation provided good 1-year durability in patients with isolated persistent AF irrespective of postprocedural electrophysiological confirmation. Seventy-percent of the TTA group did not need additional catheter ablation.

Extent of late gadolinium enhancement (LGE) quantified by cardiac magnetic resonance was reportedly helpful for predicting the risk of ventricular tachyarrhythmias (VTA) in hypertrophic cardiomyopathy (HCM) patients. However, only a few data exist on the clinical implication of semi-quantitative assessment LGE extent in this patient population. The extent of left ventricular (LV) LGE was measured in 310 consecutive HCM patients using semi-quantitative (summing the LV segments with LGE, spatial extent) and quantitative (calculating the LGE volume percentage [vol% of LGE] against the total LV myocardial volume) methods, respectively. LV LGE was detected in 255 (82%) patients, most frequently in the mid-LV septum (n = 160, 52%). During the 49 ± 45 month follow-up, spontaneous VTA events were observed in 48 patients (16%) including aborted sudden cardiac death (SCD), appropriate defibrillator shock, and non-sustained VTA. The extent of LGE assessed by the two different methods showed a strong positive correlation (Spearman’s r = 0.63, P

Background Electrical cardioversion (ECV) is an effective method for restoring sinus rhythm after atrial fibrillation (AF). However, early recurrence of AF occurs in a significant number of patients after ECV. This study aimed to identify electrocardiographic (ECG) predictors of early AF recurrence after ECV. Methods A total of 272 patients with persistent AF undergoing successful ECV were consecutively enrolled in this study. We investigated clinical, echocardiographic, and ECG data. The 12‐lead ECG parameters were measured during sinus rhythm right after ECV using a digital caliper. The early AF recurrence was defined as recurrence within 2 months. Results Of the 272 patients, 165 patients (60.7%) experienced an early AF recurrence. Maximum P‐wave duration (PWD) in limb leads (OR: 1.086; 95% CI: 1.019–1.157; p = .012) and P‐terminal force (PTF) in V1 (OR: 1.019; 95% CI: 1.004–1.033; p = .011) were independent predictors of early AF recurrence after ECV. The optimal cutoff value of the maximum PWD in limb leads for predicting early AF recurrence was 134 ms, characterized by 90.3% sensitivity and 72.0% specificity. Likewise, the optimal cutoff value of PTF in V1 was 50 ms × mm, characterized by 80.0% sensitivity and 64.5% specificity. Conclusion A longer PWD (>134 ms) and a larger PTF (>50 ms × mm) were useful predictors of early recurrence of AF after successful ECV in clinical practice. A more effective rhythm control therapy such as catheter ablation or rate control strategy rather than a repeat ECV should be considered.

Background This study aims to investigate the current status of AF (atrial fibrillation) catheter ablation in Korea. Methods The patients who underwent AF catheter ablation from September 2017 to December 2019 were prospectively enrolled from 37 arrhythmia centers. Demographic data, procedural characteristics, the extent of catheter ablation, acute success of the ablation lesion set, rate and independent risk factor for recurrence of AF were analyzed. Results A total of 2402 AF patients [paroxysmal AF (PAF) 45.7%, persistent AF (PeAF) 43.1% and redo AF 11.2%] were included. Pulmonary vein isolation (PVI) was performed in 2378 patients (99%) and acute success rate was 97.9%. Additional non-PV ablation (NPVA) were performed in 1648 patients (68.6%). Post-procedural complication rate was 2.2%. One-year AF-free survival rate was 78.6% and the PeAF patients showed poorer survival rate than the ones with other types (PeAF 72.4%, PAF 84.2%, redo AF 80.0%). Additional NPVA did not influence the recurrence of AF in the PAF patients (PVI 17.0% vs. NPVA 14.6%, P value 0.302). However, it showed lower AF recurrence rate in the PeAF patients (PVI 34.9% vs. NPVA 24.4%, P value 0.001). Valvular heart disease, left atrial diameter, PeAF, PVI alone, need of NPVA for terminating AF, and failed ablation were independent predictors of AF recurrence. Conclusions Additional NPVA was associated better rhythm outcome in the patients with PeAF, not in the ones with PAF. The independent risk factors for AF recurrence in Korean population were similar to previous studies. Further research is needed to discover optimal AF ablation strategy.

Background Recent trials demonstrated the safety and efficacy of cryoballoon ablation prior to antiarrhythmic drug (AAD) usage in patients with paroxysmal atrial fibrillation (AF); however, global utilization and outcomes of first-line cryoablation in real-world AF patient management are unknown. Purpose To evaluate baseline characteristics and outcomes in patients selected for first-line cryoablation for treatment of AF. Methods The Cryo Global Registry (NCT02752737) is an ongoing, prospective, multicenter registry. In this analysis, AF patients with an index cryoballoon ablation performed according to local standards of care at 58 centers in 26 global countries were included. Subjects with no prior failed antiarrhythmic drug (AAD) usage and not taking an AAD at baseline were considered first-line and compared to drug-refractory patients who had failed an AAD prior to enrollment in the study and/or were taking an AAD at baseline. Baseline characteristics, serious procedure-related complication rates, and 12-month freedom from a ≥30sec AF/atrial flutter (AFL)/atrial tachycardia (AT) recurrence after a 90-day blanking period were compared between the groups. Results In total, 31% of the 1,394 patients (433 first-line, 961 drug-refractory) received a first-line cryoablation. The proportion of first-line enrollments by world region (3.7%-53.5%) and countries within region (i.e. EU: 0–59%) varied widely. Drug-refractory patients failed a mean of 1.2±0.5 AADs prior to cryoablation. First-line and drug-refractory patients were similar in age (60±13 vs 61±11), sex (35.1% vs 36.8% female), and CHA2DS2-VASC (2.0±1.6 vs 2.1±1.6). First-line was more often paroxysmal AF (87.3% vs 80.2%), with lower BMI (27±5 vs 28±5), diagnosed with AF fewer years (2.1±3.9 vs 3.7±5.0), and had smaller left atrial diameters (39±7 vs 42±8 mm; all p0.05). Serious adverse event rates were not statistically different between first-line and drug-refractory patients (2.3% vs 3.4%, respectively; p=0.32). Freedom from AF/AFL/AT after cryoablation in first-line vs drug-refractory PAF was 90.0% (95% CI: 86.4–92.7%) and 84.4% (95% CI: 81.5–86.8%) and in first-line vs drug-refractory persistent AF was 72.9% (95% CI: 58.6–83.0%) vs 70.2% (95% CI: 62.9–76.4%), respectively. First-line ablation resulted in higher rates of freedom from arrhythmia recurrence (p=0.02). Conclusion First-line cryoablation in a real-world setting resulted in improved efficacy without increasing the risk of a safety event. These data support cryoablation as an early intervention strategy for treatment of AF. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): Medtronic, Inc.

Background Totally thoracoscopic ablation (TTA) is a minimally invasive and safe alternative to radiofrequency catheter ablation (RFCA) for patients with atrial fibrillation (AF). It has evolved over the last decades, but data are limited. The aim of this study was to report the long-term efficacy and safety of TTA through a single center experience. Methods We retrospectively analyzed all consecutive patients who underwent TTA for AF from February 2012 to December 2018. All patients were followed every 3 months after operation with 12-lead ECG and 24-hour Holter ECG monitoring. The late recurrence of AF was defined as any atrial tachyarrhythmia (ATa) sustained more than 30 s from 3 months after surgery. Results Of the total 408 patients undergoing TTA, 265 were analyzed in this study (17% paroxysmal, persistent or long standing persistent 83%, mean age 56 ± 9 years). During the mean follow-up duration 23 ± 18 months, ATa-free survival rate was 74%, 64%, 58%, 51% and 51% at 1,2,3,4 and 5 years, respectively. At the last follow-up, 75% of patients had sinus rhythm with or without additional intervention. The overall complication rate was 4.5% (12 events) and four patients (1.5%) had a stroke during follow-up. Conclusions TTA could be effective treatment option for AF. It had a very low risk of complication and could reduce stroke incidence. Further studies are needed to improve treatment strategy.

Background and Objectives: Cryoballoon ablation (CBA) and totally thoracoscopic surgical ablation (TTA) have emerged as alternatives to radiofrequency catheter ablation (RFCA) for atrial fibrillation. In this study, we describe our experience comparing patient characteristics and outcomes of RFCA, CBA, and TTA. Materials and Methods: We retrospectively analyzed data from patients who underwent RFCA, CBA, or TTA. Both atrial fibrillation (AF)- and atrial tachyarrhythmia (ATa)-free survival rates were compared using time to recurrence after a 3-month blanking period (defined by a duration of more than 30 s). All patients were regularly followed using 12-lead ECGs or Holter ECG monitoring. Results: Of 354 patients in this study, 125 underwent RFCA, 97 underwent CBA and 131 underwent TTA. The TTA group had more patients with persistent AF, a larger LA diameter, and a history of stroke. The CBA group showed the shortest procedure time (p &lt, 0.001). The CBA group showed significantly lower AF-free survival at 12 months than the RFCA and TTA groups (RFCA 84%, CBA 74% and TTA 85%, p = 0.071, p = 0.859 for TTA vs. RFCA, p = 0.038 for RFCA vs. CBA and p = 0.046 for TTA vs. CBA). There were no significant differences in ATa-free survival among the three groups (p = 0.270). There were no procedure-related adverse events in the RFCA group, but some complications occurred in the CBA group and the TTA group (6% and 5%, respectively). Conclusions: RFCA and CBA are effective and safe as first-line treatments for paroxysmal and persistent AF. In some high-risk stroke patients, TTA may be a viable option. It is important to consider patient characteristics when selecting an ablation method for AF.

The spin–orbit torque (SOT) resulting from a spin current generated in a nonmagnetic transition metal layer offers a promising magnetization switching mechanism for spintronic devices. To fully exploit this mechanism, in practice, materials with high SOT efficiencies are indispensable. Moreover, new materials need to be compatible with semiconductor processing. This study introduces W–Ta and W–V alloy layers between nonmagnetic β-W and ferromagnetic CoFeB layers in β-W/CoFeB/MgO/Ta heterostructures. We carry out first-principles band structure calculations for W–Ta and W–V alloy structures to estimate the spin Hall conductivity. While the predicted spin Hall conductivity values of W–Ta alloys decrease monotonically from −0.82 × 103 S/cm for W100 at% as the Ta concentration increases, those of W–V alloys increase to −1.98 × 103 S/cm for W75V25 at% and then gradually decrease. Subsequently, we measure the spin Hall conductivities of both alloys. Experimentally, when β-W is alloyed with 20 at% V, the absolute value of the spin Hall conductivity considerably increases by 36% compared to that of the pristine β-W. We confirm that the W–V alloy also improves the SOT switching efficiency by approximately 40% compared to that of pristine β-W. This study demonstrates a new material that can act as a spin current-generating layer, leading to energy-efficient spintronic devices. Changes to materials used in spintronics, an emerging magnetic memory technology, can reduce the energy costs associated with manipulating electron spin. When an electron from a nonmagnetic metal travels into a thin magnetic film, a twisting force known as the spin-orbit torque can emerge. Findings from researchers led by Young Keun Kim, Korea University, Seoul, and Sonny Rhim, University of Ulsan, Ulsan, Korea, may make it easier to use spin-orbit torque to switch between the on/off states of magnetic memory devices. Through a combination of theory and experiment, the team found that the nonmagnetic metal alloys played a key role in torque generation. An optimized heterostructure with an alloy film based on tungsten and smaller amounts of vanadium boosted torque-based switching efficiency by 40 percent compared to those with pristine tungsten films. Based on the first-principles calculation on the β-W based alloy structure using Ta and V, we have introduced the W–Ta and W–V alloy in between the β-W/CoFeB layer. Through the harmonic response method, we confirmed that experimentally obtained spin-Hall conductivity has fairly similar alloy compositional dependence with the theoretically calculated one. Particularly, when W80V20 alloy was placed at the β-W/CoFeB layer, the spin Hall conductivity reached (−2.77 ± 0.31) × 103 S/cm, which enhanced over 36% compared to the pristine β-W/CoFeB/MgO heterostructure.

Reduced-dose nonvitamin K antagonist oral anticoagulants (NOACs) are commonly prescribed to Asian patients with nonvalvular atrial fibrillation (NVAF). We aimed to compare the risk of stroke/systemic embolism (S/SE) and major bleeding (MB) between patients treated with reduced-dose NOACs and those treated with warfarin, using the claims database in Korea. Patients with NVAF newly initiated on oral anticoagulants (OACs, apixaban, dabigatran, rivaroxaban, and warfarin) between 1 July 2015 and 30 November 2016 were included. Among all patients with NVAF treated with OACs, 5249, 6033, 7602, and 8648 patients were treated with reduced-dose apixaban, dabigatran, rivaroxaban, and warfarin, respectively. Patients treated with reduced-dose NOACs were older and had higher CHA2DS2-VASc and HAS-BLED scores than those treated with warfarin. Compared to warfarin, all reduced-dose NOACs showed significantly lower risk of S/SE (hazard ratios (95% confidence interval), 0.63 (0.52–0.75) for apixaban, 0.51 (0.42–0.61) for dabigatran, and 0.67 (0.57–0.79) for rivaroxaban) and MB (0.54 (0.45–0.65) for apixaban, 0.58 (0.49–0.69) for dabigatran, 0.73 (0.63–0.85) for rivaroxaban). In the real-world practice among Asians with NVAF, all reduced-dose NOACs were associated with a significantly lower risk of S/SE and MB compared to those of warfarin.

This study documents our experience with acute forearm compartment syndrome after percutaneous transradial coronary artery intervention and suggests several strategies to achieve good results. A retrospective review identified the medical records of four patients with acute forearm compartment syndrome after transradial intervention who were treated by urgent fasciotomy. The mean time from the onset of symptoms to operation was 5.7 hours. In three cases bleeding was from radial artery rupture at the puncture site, and one case was caused by brachial artery rupture at the level of the distal humerus and radial artery rupture at the level of proximal forearm. We obtained satisfactory results without any complications. If acute forearm compartment syndrome after transradial intervention is diagnosed, the site of bleeding should be identified preoperatively. Early surgical decompression produced satisfactory results even in elderly patients. Level of evidence: IV

Background Annually, about 80% of the Korean elderly aged ≥65 years receive influenza vaccination. Repeated annual vaccination has been suggested as an important factor of poor influenza vaccine effectiveness (VE), though reported conflicting results. Methods During the consecutive A/H3N2-dominant influenza seasons between 2012 and 2015, we comparatively evaluated the VE (repeated vs. current season only) against laboratory-confirmed influenza, pneumonia and hospitalization in the elderly aged ≥65 years with influenza-like illness (ILI). Clinical and demographic data were collected prospectively, and vaccination status of prior and current seasons was verified using the immunization registry data of Korean Centers for Disease Control and Prevention. Results During the first A/H3N2-dominant season in 2012–2013, influenza vaccine showed statistically significant effectiveness against influenza A infection only and when vaccinated in the current season only (VE 53%, 95% CI 15–77). In the latter two seasons (2013–2015 years), the adjusted VE for influenza A was indistinguishable between repeated vaccination and vaccination in the current season only. Conclusion During consecutive influenza A/H3N2 epidemics, poor influenza vaccine effectiveness may be more pronounced among the elderly population with a high annual vaccine uptake rate.

Background and objectives The association between thyroid dysfunction and supraventricular tachyarrhythmia (SVT) other than atrial fibrillation (AF) is not well elucidated. We hypothesized that patients with suspected or documented SVT have undetected thyroid dysfunction more frequently than general population. Subjects and methods Patients with symptoms suggestive of SVT other than AF who were planned to undergo an EP study at our center were eligible for this study. Patients with known thyroid disease, medications affecting thyroid function test (TFT) or atrial fibrillation were excluded. The primary outcome was prevalence of TFT abnormalities in the study population. The secondary outcome was prevalence of clinically significant arrhythmia during the EP study. Results A total of 533 patients were analyzed. Patients were divided into the two groups according to TFT results. Fifty-six (10.5%) patients had abnormal TFT results (thyroid dysfunction group), while 477 (89.5%) had normal thyroid function (euthyroidism group). The overall prevalence of thyroid dysfunction was 10.5%. The thyroid dysfunction group showed a tendency for higher induction of clinically significant SVT than the euthyroidism group. However, thyroid dysfunction was not an independent predictor of clinically significant SVT during EP study. Conclusion In this study, patients with suspected SVT who were planned for EP study had a relatively high incidence of thyroid dysfunction. Clinically significant arrhythmia tended to be induced more frequently in the thyroid dysfunction group than in the euthyroidism group. Further investigations are needed to verify the clinical implications of TFT in patients with SVT other than AF.

The aim of this study was to identify associations between the smoothness index of central SBP (CSBP) and changes of ambulatory carotid femoral pulse wave velocity in response to 20-week treatments with losartan and amlodipine vs. losartan and hydrochlorthiazide combinations.For 142 (losartan and hydrochlorthiazide: 72, losartan and hydrochlorthiazide: 70) patients examined with ambulatory central blood pressure (BP) monitoring device, we calculated smoothness indices and trough-to-peak ratios of brachial SBP, CSBP, ambulatory pulse pressure amplification (APPA), ambulatory augmentation index at heart rate 75 beats per minute (AAIx75) and ambulatory carotid femoral pulse wave velocity (AcfPWV).Mean age was 58.9 ± 12.3 years, and women accounted for 25.9%. Changes in office SBP/DBP were not different between groups (losartan and hydrochlorthiazide: -15.2 ± 15.0/-7.8 ± 8.0 vs. losartan and amlodipine: -14.9 ± 13.7/-9.2 ± 7.5 mmHg). Reduction of 24-h CSBP was not significantly different (losartan and hydrochlorthiazide: 6.4 ± 1.1 vs. losartan and amlodipine: 9.2 ± 1.1 mmHg, P = 0.074). Reduction in nocturnal AcfPWV was greater in the losartan and amlodipine group (losartan and hydrochlorthiazide: 0.09 ± 0.05 vs. losartan and amlodipine: 0.26 ± 0.05 m/s, P = 0.0216). Intraindividual SIs for CSBP were higher in the losartan and amlodipine group (0.40 ± 0.57 vs. 0.65 ± 0.74, P = 0.022). In multivariable regression analysis, smoothness index of CSBP was independently associated with the losartan and amlodipine group. In model additionally considering the changes in arterial stiffness, decrease in AcfPWV instead of the treatment group was independently associated with smoothness indices. In mediation analysis, smoothness index was fully mediated by reduction in night-time AcfPWV.Losartan and amlodipine combination was superior to the losartan and hydrochlorthiazide combination in terms of achieving higher smoothness index for CSBP after 20-week treatments. The effect of losartan and amlodipine on smoothness index was fully mediated by reduction of night-time AcfPWV.

Complicated epidermoid cysts (ECs) occur commonly on the back, but few reports have described their management. We present our experience in managing patients with ECs on the back using a keystone-design perforator island flap (KDPIF) reconstruction, thereby focusing on reduction and redistribution of wound tension. Altogether, 15 patients (average age, 48.067 ± 14.868 years) underwent KDPIF reconstructions after complete excision of complicated ECs on the back. We retrospectively reviewed the medical records and clinical photographs of all patients. Final scar appearance was evaluated using the Patient and Observer Scar Assessment Scale (POSAS). All patients had ruptured ECs, while 6 patients also had cellulitis of the surrounding tissues. All defects, after complete excision of ECs and debridement of surrounding unhealthy tissues, were successfully covered with KDPIF. The mean ‘tension-change’ at the defect and donor sites was −4.73 ± 0.21 N and −4.88 ± 0.25 N, respectively (p

Background/Aims Although cardiovascular (CV) risk factors are well established, some patients experience acute myocardial infarction (AMI) even without any risk factors. Methods We analyzed total 11,390 patients (63.6 ± 12.6 years old, 8,401 males) with AMI enrolled in Korea Acute Myocardial Infarction Registry-National Institute of Health from November, 2011 to December, 2015. Patients were divided into two groups according to the presence of any CV risk factors (group I, without risk factors, n = 1,420 [12.5%]; group II, with risk factors, n = 9,970 [87.5%]). In-hospital outcomes were defined as in-hospital mortality and complications. One-year clinical outcomes were defined as the composite of major adverse cardiac events (MACE). Results Group I was older (67.3 ± 11.6 years old vs. 63.0 ± 12.7 years old, p < 0.001) and had higher prevalence of female gender (36.2% vs. 24.8%, p < 0.001) than the group II. Group I experienced less previous history of angina pectoris (7.0% vs. 9.4%, p = 0.003) and the previous history of cerebrovascular accidents (3.4% vs. 6.9%, p < 0.001). In-hospital mortality (2.6% vs. 3.0%, p = 0.450) and complications (20.6% vs. 20.0%, p = 0.647) were no differences between the groups. And 1 year clinical outcomes (5.7% vs. 5.1%, p = 0.337) were no differences between the groups. In multivariate logistic regression analysis, serum creatinine level (hazard ratio, 1.35; 95% confidence interval, 1.05 to 1.75; p = 0.021) were independent predictors of 1 year MACE in patients without any CV risk factors. Conclusions Elderly female patients were prone to develop AMI even without any modifiable CV risk factors. We suggest that more intensive care is needed in AMI patients without any CV risk factors who have high serum creatinine levels.

In this study, the design of an magnetorheological elastomer flexible coupling whose torsional stiffness can be controlled by an embedded magnetic field generator is proposed. It is designed to minimize the torsional vibration transmission between shafts adaptively to the dynamic disturbance. The coupling insert is composed of magnetorheological elastomer which is a smart material whose stiffness can be controlled by an external magnetic field. This article also proposes a compact magnetic field generator which can be fitted inside the coupling hubs, to control the torsional stiffness of the magnetorheological elastomer. The finite element method was used to design and estimate the dynamic stiffness variation of the magnetorheological elastomer coupling due to the applied magnetic field and disturbance frequency. Also, torsional vibration experiments were conducted to validate the performance of the proposed magnetorheological elastomer coupling. Results showed that it can adaptively tune in a range of frequencies between 16.8 and 23.5 Hz and has 95.7% stiffness variation under magnetic field of 150mT. The proposed system is expected to achieve a higher MRE effect with a softer base matrix.