1.Interventricular septal hematoma following left bundle branch area pacing: a rare case with atypical arrhythmic presentation
Seongjin PARK ; Juwon KIM ; Seung-Jung PARK ; Kyoung-Min PARK ; Young Keun ON ; Ju Youn KIM
International Journal of Arrhythmia 2026;27(1):e7-
Background:
Left bundle branch area pacing (LBBAP) provides physiologic ventricular activation but requires deep lead penetration into the interventricular septum, which can rarely cause various complications.Case presentation: A 57-year-old woman with high-degree atrioventricular block underwent dual-chamber pacemaker implantation with stylet-driven LBBAP via the left axillary vein. Within hours, she developed nausea, vomiting, and frequent ventricular premature contractions with non-sustained ventricular tachycardia, while remaining hemodynamically stable. Transthoracic echocardiography revealed a well-circumscribed echo lucent mass in the mid interventricular septum (15.6 × 24.7 mm) consistent with hematoma, without pericardial effusion or left ventricular outflow tract obstruction. In the absence of clinical deterioration, a conservative strategy with close rhythm monitoring and serial echocardiography was chosen. The hematoma regressed progressively with near-complete resolution at two weeks, and the patient remained asymptomatic with stable lead function at 6-month follow-up.
Conclusions
Interventricular septal hematoma is a rare complication of LBBAP that may present predominantly with ventricular arrhythmia. In hemodynamically stable patients without mechanical compromise, careful surveillance can allow successful conservative management without surgical intervention.
2.Acute Heart Failure Across the Ejection Fraction Spectrum: Phenotypes, Management, and Outcomes From Nationwide KorHF III Registry
Huijin LEE ; Eung Ju KIM ; Seong Woo HAN ; Seong-Mi PARK ; Hyung-Seop KIM ; Myung-Chan CHO ; Hyo-Suk AHN ; Mi-Seung SHIN ; Seok-Jae HWANG ; Jin-Ok JEONG ; Dong Heon YANG ; Junho HYUN ; Jin Oh CHOI ; Hae-Young LEE ; Byung-Su YOO ; Seok-Min KANG ; Dong-Ju CHOI ; Hyun-Jai CHO ;
International Journal of Heart Failure 2026;8(1):43-55
Background and Objectives:
Clinical characteristics and outcomes in acute heart failure (AHF) vary by phenotype. We assessed phenotype-specific features, treatment patterns, and outcomes in a nationwide Korean cohort.
Methods:
The Korean Heart Failure III registry prospectively enrolled 7,351 AHF admissions at 47 hospitals. Among 6,777 patients with available left ventricular ejection fraction (EF), phenotypes were defined as heart failure with reduced EF (HFrEF, ≤40%), mildly reduced EF (HFmrEF,41–49%), or preserved EF (HFpEF, ≥50%). The primary endpoint was a 12-month composite of all-cause death or heart transplantation, evaluated from index admission and, among hospital survivors, from discharge. We used inverse probability weighting (multinomial generalized boosted models with stabilized, trimmed weights) and weighted Cox proportional-hazards models to estimate hazard ratios (HRs).
Results:
Phenotype distribution was 58.9% HFrEF, 13.6% HFmrEF, and 27.5% HFpEF. Crude 12-month composite rates from index admission were 13.4% (HFrEF), 12.7% (HFmrEF), and 16.8% (HFpEF). After weighting, from index admission, HFmrEF (HR, 0.892; 95% confidence interval [CI], 0.731–1.088) and HFpEF (HR, 1.101; 95% CI, 0.939–1.291) did not differ from HFrEF; from discharge, HFpEF had modestly higher risk (HR, 1.207; 95% CI, 1.008–1.445) whereas HFmrEF did not (HR, 1.039; 95% CI, 0.844–1.279). Hyponatremia and chronic kidney disease were consistent adverse markers, while angiotensin-converting enzyme inhibitor/ angiotensin II receptor blocker use at discharge was protective.
Conclusions
Across the EF spectrum, phenotypes showed distinct profiles and risk. Postdischarge risk was modestly higher in HFpEF, supporting phenotype-tailored care and systematic discharge optimization in Korean patients with AHF.
3.Korean Thyroid Association Guidelines on the Management of Differentiated Thyroid Cancers; Part II. Follow-up Surveillance after Initial Treatment 2026
Eun Kyung LEE ; Seung Heon KANG ; Bon Seok KOO ; Mijin KIM ; Min Joo KIM ; Bo Hyun KIM ; Ji Won KIM ; Dong Gyu NA ; Sohyun PARK ; Ji-In BANG ; Kyorim BACK ; Youngduk SEO ; Young-Ik SON ; Young Shin SONG ; Dong Yeob SHIN ; Jong-Hyuk AHN ; Hwa Young AHN ; So Won OH ; Ho-Ryun WON ; Won Sang YOO ; Min Kyoung LEE ; Sang-Woo LEE ; Jeongmin LEE ; Ji Ye LEE ; Dong-Jun LIM ; Ki-Wook CHUNG ; Ari CHONG ; Jin Hyang JUNG ; Sun Wook CHO ; Yoon Young CHO ; Chae Moon HONG ; Young Joo PARK ;
International Journal of Thyroidology 2026;19(1):1-40
In patients with differentiated thyroid cancer (DTC), initial recurrence risk stratification based on clinical, histopathological, and perioperative data remains the key determinant for guiding management strategies during the first 1-2 years post-treatment. However, the adoption of ongoing risk stratification (ORS), which dynamically reassesses risk by integrating longitudinal clinical data and treatment response, enables more precise long-term prognostic assessment and facilitates highly individualized management. Building upon recent guidelines, the 2026 KTA guideline has been further refined by incorporating robust evidence from large-scale national cohorts and comprehensive systematic reviews. These updated recommendations outline contemporary concepts of ORS, risk-adapted TSH suppression targets, optimized surveillance modalities for recurrence detection, and disease-specific long-term follow-up strategies. Reflecting the paradigm shift toward de-escalated treatment, this revision integrates evolved perspectives on TSH suppression intensity, the clinical interpretation of thyroglobulin levels, and tailored follow-up intervals. These evidence-based recommendations aim to minimize unnecessary treatment and excessive surveillance in the large proportion of patients with excellent prognosis after initial therapy, while ensuring that each patient receives appropriately tailored and effective long-term management.
4.Biomimetic Architectural Cover Accelerates `Osseointegration of Titanium Implants
Su-Jin KIM ; Eun Chae KIM ; Weon-Young CHOI ; Seung-Jae LEE ; Je-Hwang RYU
Journal of Bone Metabolism 2026;33(1):30-39
Background:
Although various surface modifications enhance titanium (Ti) implant osseointegration, achieving rapid bone formation comparable to native healing remains challenging. Current strategies primarily focus on micro-scale topography, often overlooking the critical role of macroscopic three-dimensional (3D) architecture in osteoconduction.
Methods:
We hypothesized that mimicking native bone’s porous architecture is key to accelerating osseointegration. First, we verified the impact of structural continuity by comparing standard Ti implants with decellularized bone grafts in a mouse calvaria defect model. Subsequently, we developed a biomimetic polycaprolactone (PCL)-based 3D architectural cover (Cover-type) and evaluated its osseointegration efficacy in a rat femur model against conventional Ti implants.
Results:
The mouse study confirmed that decellularized bone integrated significantly faster than Ti, highlighting the necessity of 3D continuity. In the rat model, micro-computed tomography analysis indicated a clear trend of increased bone formation in the Cover-type group, though statistical significance was limited by sample size. However, histological analysis confirmed a statistically significant enhancement in bone-to-implant contact compared to controls (P<0.05). The PCL structure served as a scaffold for cell migration, effectively bridging the implant-bone gap.
Conclusions
These findings suggest that providing a bone-like 3D environment via a PCL cover may enhance histological osseointegration, rather than relying solely on surface chemistry.
5.Ethnic Heterogeneity in Reproductive Risk Factors for Breast Cancer, With a Focus on Asian Populations:A Meta-analysis
Youjin HONG ; Soseul SUNG ; Woojin LIM ; Sungji MOON ; Kwang-Pil KO ; Jung Eun LEE ; Inah KIM ; Sun Ha JEE ; Sun-Seog KWEON ; Min-Ho SHIN ; Sangmin PARK ; Seung-Ho RYU ; Sun Young YANG ; Jeongseon KIM ; Sang-Wook YI ; Sue K. PARK
Journal of Cancer Prevention 2026;31(1):20-27
suggest that some reproductive factors associated with BC differ across ethnicities and time trends, perhaps due to the prevalence of reproductive factors and the baseline hazard of BC.
6.Management of Abrupt Vessel Closure During Percutaneous Coronary Intervention: A Narrative Review
Yongwhan LIM ; Seok OH ; Joon Ho AHN ; Seung Hun LEE ; Dae Young HYUN ; Kyung Hoon CHO ; Min Chul KIM ; Doo Sun SIM ; Young Joon HONG ; Ju Han KIM ; Youngkeun AHN
Journal of Cardiovascular Intervention 2026;5(1):1-10
Abrupt vessel closure (AVC) is a complication of percutaneous coronary intervention (PCI) and is defined as the sudden cessation of forward coronary blood flow due to a variety of mechanisms. The incidence of AVC has markedly decreased from approximately 3.0% in the early era to about 0.3% today. Nevertheless, cardiovascular interventionists must remain prepared to manage AVC effectively, given its significant impact on clinical outcomes.AVC can arise from several mechanisms, including dissection, intramural hematoma, intracoronary thrombosis, air embolism, vasospasm, and no-reflow. The clinical impact of AVC varies depending on the extent of myocardium affected, ranging from asymptomatic events or transient ischemic chest pain to cardiogenic shock or cardiac arrest. Both a general approach for stabilizing hemodynamic consequences and an etiology-specific management strategy are essential. Hasty decision-making may worsen the situation, whereas a structured approach—focused on hemodynamic stabilization, logical diagnostic processes, and targeted interventions—can improve outcomes. In this narrative review, we describe the mechanisms underlying each etiology, outline mechanism-specific management strategies, and discuss general approaches to managing patients with AVC through logical diagnostic and treatment processes. We hope this review offers valuable insights into this uncommon but significant complication and enhances readers’ skills in managing AVC more effectively during PCI.
7.Comparison of reference management software with new artificial intelligence-based tools
Jae Gyeong JIN ; Seung Gyu LEE ; Jea Hyeun PARK ; Jang Won HAN ; Jae Young KIM ; Jungirl SEOK ; Jeong-Ju YOO
Journal of Educational Evaluation for Health Professions 2026;23(1):2-
Reference management software (RMS) represents a cornerstone of modern academic writing and publishing. For decades, programs such as EndNote, Zotero, and Mendeley have played central roles in facilitating citation organization, bibliography formatting, and collaborative scholarship. Although each platform has introduced unique innovations, persistent limitations remain, particularly with respect to usability, accessibility, and accuracy. In parallel, the rise of generative artificial intelligence has introduced an unprecedented challenge: the inadvertent inclusion of fabricated or incorrect references mistakenly incorporated into manuscripts. This phenomenon has exposed a critical limitation of traditional RMS platforms, namely their inability to verify reference authenticity. Against this backdrop, new solutions have emerged. One such example is CiteWell (https://citewell.org/), an artificial intelligence (AI)-era RMS that introduces several notable innovations, including PubMed-integrated verification, an intuitive interface for new users, customizable journal-specific styles, and multilingual accessibility. This review provides a comprehensive historical overview of RMS, evaluates the strengths and weaknesses of major platforms, and positions emerging AI-based tools as a new paradigm that combines traditional reference management with essential safeguards for contemporary academic challenges.
8.Beneficial Effects and Factors Associated With Provision of Breast Milk at Neonatal Intensive Care Unit Discharge to Very Low Birth Weight Infants: A Nationwide Cohort Study in Korea
Seung Hyun SHIN ; Hyun Seo KIM ; Da Min CHOI ; Soon-Young HWANG ; Eui Kyung CHOI
Journal of Korean Medical Science 2026;41(1):e20-
Background:
The incidence of preterm birth in Korea increased from 6.5% in 2013 to 9.7% in 2020. Very low birth weight (VLBW) infants, defined as those weighing < 1,500 g, are particularly vulnerable to numerous health risks. Breast milk provision reduces the incidence of complications in this vulnerable population. The objective of this study was to examine the rate and factors associated with breast milk provision at neonatal intensive care unit (NICU) discharge and to investigate its potential effects on growth and developmental outcomes at 18–24 months corrected age (CA).
Methods:
We conducted this cohort study using data from over 70 NICUs participating in the Korean Neonatal Network. VLBW infants born between January 2019 and December 2020 at a gestational age of 23 +0 to 31 +6 weeks were included. Discharge feeding types were analyzed of 2,490 infants, while follow-up assessments of growth and neurodevelopmental outcomes at 18–24 months of CA were available for 1,426 infants. Propensity score matching was used for comparative analysis.
Results:
The rate of breast milk provision at discharge among VLBW infants was 55.9% in 2019 and 56.5% in 2020. Factors that were positively associated with breast milk feeding included higher maternal education level and antenatal steroid use. In contrast, maternal hypertensive disorders, cesarean section, and severe neonatal morbidities (e.g., necrotizing enterocolitis) were correlated with lower breast milk feeding rates at the time of discharge.The provision of breast milk at discharge was not associated with a higher risk of suboptimal growth (below two standard deviations) compared to control infants at 18–24 months of CA. Neurodevelopmental assessments indicated that breast milk was associated with a reduced risk of developmental delay (adjusted odds ratio, 0.72; 95% confidence interval, 0.56–0.94) at follow-up.
Conclusion
Breast milk provision to VLBW infants at NICU discharge in Korea was comparable to that in other countries. This nationwide study highlights the critical role of breast milk in promoting the neurodevelopment of VLBW infants. Future efforts should focus on identifying the barriers to breast milk provision to improve health outcomes in vulnerable populations.
9.Nationwide Survey on Endoscopic Submucosal Dissection for Early Gastric Cancer in Korea: Results From the Korean College of Helicobacter and Upper Gastrointestinal Research (KCHUGR) 2023 Survey
Jae Yong PARK ; Jeong Hoon LEE ; Tae-Se KIM ; Da Hyun JUNG ; Bong Eun LEE ; Yonghoon CHOI ; Wan-Sik LEE ; Young-Il KIM ; Sun Hyung KANG ; Hyunsoo CHUNG ; Su Jin KIM ; Joon Sung KIM ; Donghoon KANG ; Su Youn NAM ; Seung Han KIM ; Hyo-Joon YANG ; Hyun LIM ; Jin LEE ; Seon-Young PARK ; Seung-Woo LEE ; Sun Moon KIM ; Sam Ryong JEE ; Dae Young CHEUNG ; Chung Hyun TAE ; Seokin KANG ; Sung Chul PARK ; Seung In SEO ; Cheol Min SHIN ; Kee Don CHOI ; Jong Yeul LEE ;
The Korean Journal of Helicobacter and Upper Gastrointestinal Research 2026;26(1):50-59
Objectives:
Endoscopic submucosal dissection (ESD) has become a standard minimally invasive treatment for selected patients with early gastric cancer (EGC). This study presents the first nationwide survey of patients with EGC treated with ESD in 2023, conducted by the Korean College of Helicobacter and Upper Gastrointestinal Research.
Methods:
Data were retrospectively collected from participating referral centers across Korea using a standardized case report form covering patient characteristics, tumor features, procedural details, histopathological findings, and clinical outcomes. Descriptive and comparative analyses were conducted to summarize nationwide ESD practice patterns and outcomes.
Results:
Data from 5460 ESD cases from 5250 patients across 27 institutions were analyzed. The mean age was 67.4 years, with 74.1% males. Multiple synchronous lesions were identified in 3.7%. Most lesions were located in the lower third of the stomach (64.0%), and differentiated-type adenocarcinomas accounted for 87.8%. The en bloc and complete resection rates were 99.2% and 91.4%, respectively. Curative resection was achieved in 80.5%, whereas local non-curative resection (L-NCR) and surgical non-curative resection (S-NCR) were identified in 2.8% and 16.7%, respectively. Additional surgery was performed more frequently in patients with S-NCR than in those with L-NCR (59.3% vs. 24.7%). The bleeding and perforation rates were 3.6% and 0.9%, respectively, and were mostly managed conservatively or endoscopically. The median length of hospitalization was 4.0 days.
Conclusions
This first nationwide survey provides a comprehensive overview of the current practice of EGC treatment using ESD in Korea, demonstrating high technical success and safety, and establishing a baseline dataset for future longitudinal research.
10.Treatment of Helicobacter pylori Infection in Korea: An Evidence-Based Analysis of the Upcoming 2025 Guideline
Chang Seok BANG ; Seung Joo KANG ; Su Youn NAM ; Sung Eun KIM ; Seung Young KIM ; Hyunchul LIM ; Chung Hyun TAE ; Moon Won LEE ; Seung Han KIM ; Hye-Kyung JUNG ; Byung-Wook KIM
The Korean Journal of Helicobacter and Upper Gastrointestinal Research 2026;26(1):23-36
The efficacy of clarithromycin-containing triple therapy (TT) against Helicobacter pylori has declined in Korea, with recent first-line eradication rates falling below 70%. Clarithromycin resistance exceeded 30%, undermining the standard regimen for H. pylori. These trends necessitate a change in the treatment strategy. This review analyzed the shift proposed in the draft of the 2025 Korean H. pylori guidelines. We examined the rationale for abandoning TT as a first-line empirical therapy and the establishment of a new dual-pillar strategy: 1) the declining role of clarithromycin-containing TT as a first-line treatment and 2) polymerase chain reaction (PCR)-based tailored therapy as the recommended precision approach. We explored the 1) emergence of new empirical regimen options, 2) application of tailored therapy, and 3) adoption of potassium-competitive acid blockers (P-CABs). Empirical regimens have shifted toward four-drug combinations to achieve higher cure rates. Concomitant therapy (proton-pump inhibitor [PPI] or P-CAB+amoxicillin+clarithromycin+metronidazole) offers high efficacy but raises concerns about antibiotic overuse. As a compromise, bismuth-augmented triple regimens (adding bismuth to TT) are now recommended; these modified quadruple therapies (e.g., PACB: PPI+amoxicillin+clarithromycin+bismuth, or PAMB: PPI+amoxicillin+metronidazole+bismuth) significantly improve eradication rates without requiring a third antibiotic class. Regarding tailored therapy, PCR-based domestic clinical research data consistently achieves ≥90% cure rates in first-line treatment—markedly higher than empirical TT in Korea. Economic analyses supported the cost-effectiveness of this approach. The guideline algorithm for salvage therapy was clarified. Bismuth quadruple therapy has been confirmed as the standard second-line treatment. For third-line therapy, we analyzed the efficacy of levofloxacin-based regimens, rifabutin-based therapy, and bismuth add-on therapy with two previously unused antibiotics. The 2025 Korean guidelines establish quadruple therapies as the new standard through a dual strategy: pragmatic empirical treatment and PCR-guided tailored therapy, with P-CABs and bismuth-based regimens as key components.

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