Background and Objectives: Hypertrophic cardiomyopathy (HCM) increases the risk of sudden cardiac death. Despite international guidelines for sudden death prevention and implantable cardiac defibrillator (ICD) use, clinical practices vary. This study assessed the practices and opinions of Korean cardiologists on HCM management, focusing on ICD use and reimbursement policies. Methods: A structured electronic survey was distributed to members of the Korean Society of Cardiology, covering HCM management, ICD preferences, and reimbursement policies. Results: A total of 119 cardiologists participated, with most being arrhythmia specialists (56.3%) and university professors (81.5%). Cardiac magnetic resonance imaging and genetic testing were underutilized (30.3% and 11.8%, respectively). Beta-blocker-refractory premature ventricular complexes were primarily managed with continued medical therapy (77.3%). ICD preferences varied by physician specialty and patient age, with subcutaneous ICDs preferred in younger patients and dual-chamber ICDs in older patients. Nearly half of respondents believed ICD reimbursement criteria required revision. Conclusions Significant variability in HCM management exists among Korean cardiologists, influenced by restrictive reimbursement criteria rather than clinical guidelines. Updated reimbursement policies and improved access to advanced diagnostics are needed to align with international standards and optimize patient care.

Background/Aims: The reimbursement policy for cryptogenic stroke (CS) was expanded in November 2018 from recurrent strokes to the first stroke episode. No reports have demonstrated whether this policy change has affected trends in implantable loop recorder (ILR) utilization. Methods: We identified patients who received an ILR implant using the Korea Health Insurance Review and Assessment Service database between July 2016 and October 2021. Patients meeting all the following criteria were considered to have CS indication: 1) prior stroke history, 2) no previous history of atrial fibrillation or flutter (AF/AFL), and 3) no maintenance of oral anticoagulant for ≥4 weeks within a year before ILR implant. AF/AFL diagnosed within 3 years after ILR implant or before ILR removal was considered ILR-driven. Results: Among 3,056 patients, 1,001 (32.8%) had CS indications. The total ILR implant number gradually increased for both CS and non-CS indications and the number of CS indication significantly increased after implementing the expanded reimbursement policy. The detection rate for AF/AFL was 26.3% in CS patients over 3 years, which was significantly higher in patients implanted with an ILR within 2 months after stroke than those implanted later. Conclusions The expanded coverage policy for CS had a significant impact on the number of ILR implantation for CS indication. The diagnostic yield of ILR for AF/AFL detection seems better when ILR is implanted within 2 months than later. Further investigation is needed to demonstrate other clinical benefits and the optimal ILR implantation timing.

BACKGROUND: Although device-based optimization has been developed to overcome the limitations of conventional optimization methods in cardiac resynchronization therapy (CRT), few real-world data supports the results of clinical trials that showed the efficacy of automatic optimization algorithms. We investigated whether CRT using the adaptive CRT algorithm is comparable to non-adaptive biventricular (BiV) pacing optimized with electrocardiogram or echocardiography-based methods. METHODS: Consecutive 155 CRT patients were categorized into 3 groups according to the optimization methods: non-adaptive BiV (n = 129), adaptive BiV (n = 11), and adaptive left ventricular (LV) pacing (n = 15) groups. Additionally, a subgroup of patients (n = 59) with normal PR interval and left bundle branch block (LBBB) was selected from the non-adaptive BiV group. The primary outcomes included cardiac death, heart transplantation, LV assist device implantation, and heart failure admission. Secondary outcomes were electromechanical reverse remodeling and responder rates at 6 months after CRT. RESULTS: During a median 27.5-month follow-up, there was no significant difference in primary outcomes among the 3 groups. However, there was a trend toward better outcomes in the adaptive LV group compared to the other groups. In a more rigorous comparisons among the patients with normal PR interval and LBBB, similar patterns were still observed. CONCLUSION: In our first Asian-Pacific real-world data, automated dynamic CRT optimization showed comparable efficacy to conventional methods regarding clinical outcomes and electromechanical remodeling.
Bundle-Branch Block ; Cardiac Resynchronization Therapy ; Death ; Electrocardiography ; Follow-Up Studies ; Heart Failure ; Heart Transplantation ; Humans ; Immunodeficiency Virus, Bovine

BACKGROUND AND OBJECTIVES: The safety and efficacy of implantable cardioverter-defibrillator (ICD) for Korean is unclear. We investigated the clinical characteristics and outcomes of Korean patients undergoing ICD for primary or secondary prevention. MATERIALS AND METHODS: From October 1999 to December 2016, 396 cases (365 patients) of ICD implantation were performed: Baseline characteristics, procedural findings, and clinical outcome data were collected retrospectively from our ICD registry. The primary outcome was composite of cardiac death, appropriate shock or antitachycardia pacing. RESULTS: Among 365 patients, 91 patients (25.9%) had ICD for primary prevention and 274 patients (75.1%) were for secondary prevention (51.2±17.10 years, male was 80.8%). The median follow-up period was 3.1 years (interquartile range: 1.6–6.0 days). The most prevalent etiology was dilated cardiomyopathy (46.2%) in the primary prevention and idiopathic ventricular tachycardia or fibrillation (24.4%) in the secondary prevention. The primary outcome was noted in 28.6% of the primary prevention and 33.2% of the secondary prevention (P=0.44). The rate of cardiac death was 2.2% in the primary prevention and 1.8% in the secondary prevention (P=1.00). The hospitalization due to heart failure was higher in the primary prevention compared with the secondary prevention (23.1% versus 13.5%, P=0.03). ICD therapy occurred in 134 patients (36.7%). Among them, 60 patients (44.8% of ICD therapy) experienced inappropriate shock. The most common cause of inappropriate shock was atrial fibrillation of flutter (AF/AFL). CONCLUSION: The clinical efficacy and safety of ICD in Korean is consistent with the data from Western countries.
Atrial Fibrillation ; Cardiomyopathy, Dilated ; Death ; Defibrillators, Implantable* ; Follow-Up Studies ; Heart Failure ; Hospitalization ; Humans ; Male ; Primary Prevention ; Retrospective Studies ; Secondary Prevention ; Shock ; Tachycardia, Ventricular ; Treatment Outcome

PURPOSE: This study aimed to determine whether upgrade cardiac resynchronization therapy (CRT) shows better outcomes than de novo CRT. To do so, we compared the efficacy of CRT between de novo and upgrade groups, focusing particularly on the effect of upgrade CRT on patients with pacing-induced cardiomyopathy (PiCM). MATERIALS AND METHODS: PiCM was defined as new-onset dilated cardiomyopathy following pacemaker implantation in patients with baseline normal ejection fraction ≥50%. Electro-mechanical reverse remodeling and clinical outcomes were compared among the de novo (n=62), PiCM upgrade (n=7), and non-PiCM upgrade (n=8) CRT groups. RESULTS: The PiCM upgrade group showed significantly greater electro-mechanical reverse remodeling than the de novo CRT or non-PiCM upgrade groups at 6-month follow-up. The rate of super-responders was significantly higher in the PiCM upgrade group than the other CRT groups. The group factor of the PiCM upgrade was identified as an independent predictor of super-responder in multivariate analysis (odds ratio 10.4, 95% confidential interval 1.08–99.4, p=0.043). During the median follow-up of 15.8 months, the PiCM upgrade group showed the lowest rate of composite clinical outcomes, including cardiac death, heart transplantation, and heart failure-related rehospitalization (p=0.059). CONCLUSION: The upgrade CRT for PiCM patients showed better performance in terms of electro-mechanical reverse remodeling than de novo implantation or upgrade CRT in non-PiCM patients.
Cardiac Resynchronization Therapy* ; Cardiomyopathies* ; Cardiomyopathy, Dilated ; Death ; Focus Groups ; Follow-Up Studies ; Heart ; Heart Transplantation ; Humans ; Multivariate Analysis ; Ventricular Remodeling

Riata defibrillator leads were recalled due to a high failure rate. This study measured the incidence of externalized conductor (EC) and electrical dysfunction (ED) and sought to determine the predictors of ED with Riata defibrillator leads. We enrolled patients who received Riata® or Riata® ST silicone defibrillator leads at our center between January 2003 and December 2010. The presence of EC was evaluated with chest radiography. The incidence rates were measured at < 3 years, 3–5 years, and > 5 years after lead implantation. We also investigated the rates of ED and other clinical events during the follow-up period. A total of 44 patients were analyzed. The total cumulative incidence of EC was 27.3%. During the median dwell time (80 months), the incidence of ED was 22.7%. Patients with ED were younger (46.5 vs. 56.5 years, P = 0.018) and had a higher prevalence of cardiomyopathy than those without ED (60.0% vs. 20.6%, P = 0.043). ECs were most frequently detected in patients who underwent X-ray analysis 3–5 years after lead implantation (44.4%). In contrast, ED had a bimodal incidence pattern, with peaks at 5 years (7.0%) and 9 years (5.3%). There was no difference in ED-free survival rate between patients with and without EC (P = 0.628). Given the delayed occurrence of EC and ED after implantation of Riata defibrillator leads, long-term close monitoring is critically important.
Cardiomyopathies ; Defibrillators* ; Defibrillators, Implantable ; Equipment Failure ; Equipment Safety ; Follow-Up Studies ; Humans ; Incidence* ; Prevalence ; Radiography ; Silicon ; Silicones ; Survival Rate ; Thorax

No data are available on the association of serum uric acid and vasospastic angina (VSA) which has endothelial dysfunction as a possible pathophysiologic mechanism. Low uric acid level might cause adverse outcomes in VSA in connection with endothelial dysfunction. We enrolled 818 VSA patients whose uric acid level was measured at admission. Patients were categorized according to tertiles of uric acid level: group I, ≤ 4.8 mg/dL; group II, 4.9–5.9 mg/dL; and group III, ≥ 6.0 mg/dL. Primary outcome was major adverse cardiac events (MACEs), defined as a composite of cardiac death, acute myocardial infarction (MI), ischemic stroke, coronary revascularization, and rehospitalization for angina. Median follow-up duration was 49.2 months. Median uric acid values were 4.1 mg/dL for group I, 5.4 mg/dL for group II, and 6.7 mg/dL for group III. In the overall population, group II had a significantly lower incidence of MACE compared to group I (47 [17.1%] vs. 66 [24.6%]; hazard ratio [HR], 1.52; 95% confidence interval [CI], 1.02–2.26; P = 0.040) and a tendency of lower incidence of MACEs compared to Group III (47 [17.1%] vs. 62 [22.5%]; HR, 1.44; 95% CI, 0.98–2.13; P = 0.067). Among group I patients, those who received nitrates had a higher incidence of MACEs than those without nitrate therapy (P < 0.001). Low uric acid level was associated with adverse clinical outcomes, while high uric acid level had a trend toward an increase in it. Use of nitrate in patients with low uric acid level might have adverse effects on clinical outcomes of VSA.
Death ; Follow-Up Studies ; Humans ; Incidence ; Myocardial Infarction ; Nitrates ; Stroke ; Uric Acid*

A 40-year-old man presented with frequent ventricular premature complexes (VPCs) and left ventricular systolic dysfunction. He underwent radiofrequency (RF) ablation using a 3-dimensional mapping system; the ablation was performed from both the right and left outflow tract septa. Improvement in symptoms and left ventricular systolic function was noted, but VPCs recurred one month after the procedure, and 24-hour Holter monitoring revealed a VPC burden of 26%. Direct visualization of the anatomical details, catheter contact, and transmural lesion formation by intracardiac echocardiography allowed for successful performance of a redo RF ablation with higher power and longer duration at the previous ablation sites.
Adult ; Catheter Ablation* ; Catheters ; Echocardiography* ; Electrocardiography, Ambulatory ; Humans ; Ventricular Premature Complexes*

BACKGROUND AND OBJECTIVES: Non-vitamin K antagonist oral anticoagulants (NOACs) are increasingly used for stroke prevention in patients with non-valvular atrial fibrillation (NVAF), showing better efficacy and safety than warfarin. However, the rates or reasons for discontinuation of NOACs in clinical practice have not been clarified. The aim of this study was to compare 3 NOACs (apixaban, rivaroxaban, and dabigatran) with warfarin in terms of medication persistence. SUBJECTS AND METHODS: We retrospectively evaluated 1,527 patients with NVAF who had recently started taking NOACs between January 2012 and September 2015 (294 apixaban, 748 rivaroxaban, and 485 dabigatran) and compared them with 363 patients with NVAF who started taking warfarin between January 2012 and December 2013 at the Samsung Medical Center. RESULTS: The mean follow-up duration was 532 days. The discontinuation rates were higher in the 3 NOAC groups than in the warfarin group within the first year. The major causes of discontinuation were maintenance of sinus rhythm; adverse events, including all bleeding and gastrointestinal symptoms; and patients demand. The adverse event rate was lower in the warfarin group than in the 3 NOAC groups. No significant differences in thromboembolic and major bleeding events were found between the 3 NOAC groups and the warfarin group. CONCLUSION: In a single-center study, NOACs showed lower medication persistence and higher adverse event rates than warfarin during the first year.
Anticoagulants* ; Atrial Fibrillation* ; Follow-Up Studies ; Hemorrhage ; Humans ; Medication Adherence ; Retrospective Studies ; Rivaroxaban ; Stroke ; Treatment Outcome ; Warfarin

BACKGROUND/AIMS: The gastrointestinal (GI) tract often becomes involved in patients with systemic amyloidosis. As few GI amyloidosis data have been reported, we describe the clinical features and outcomes of patients with pathologically proven GI amyloidosis. METHODS: We identified 155 patients diagnosed with systemic amyloidosis between April 1995 and April 2013. Twenty-four patients (15.5%) were diagnosed with GI amyloidosis using associated symptoms, and the diagnoses were confirmed by direct biopsy. RESULTS: Among the 24 patients, 20 (83.3%) had amyloidosis light chain (AL), three (12.5%) had amyloid A, and one (4.2%) had transthyretin-related type amyloidosis. Their median age was 57 years (range, 37 to 72), and 10 patients were female (41.7%). The most common symptoms of GI amyloidosis were diarrhea (11 patients, 45.8%), followed by anorexia (nine patients, 37.5%), weight loss, and nausea and/or vomiting (seven patients, 29.2%). The histologically confirmed GI tract site in AL amyloidosis was the stomach in 11 patients (55.0%), the colon in nine (45.0%), the rectum in seven (35.0%), and the small bowel in one (5.0%). Patients with GI involvement had a greater frequency of organ involvement (p = 0.014). Median overall survival (OS) in patients with GI involvement was shorter (7.95 months; range, 0.3 to 40.54) than in those without GI involvement (15.84 months; range, 0.0 to 114.53; p = 0.069) in a univariate analysis. A multivariate analysis of prognostic factors for AL amyloidosis revealed that GI involvement was not a significant predictor of OS (p = 0.447). CONCLUSIONS: The prognosis of patients with AL amyloidosis and GI involvement was poorer than those without GI involvement, and they presented with more organ involvement and more advanced disease than those without organ involvement.
Adult ; Aged ; Amyloid Neuropathies, Familial/*diagnosis/immunology/mortality/pathology/therapy ; Biomarkers/analysis ; Biopsy ; Female ; Gastrointestinal Diseases/*diagnosis/immunology/mortality/pathology/therapy ; Gastrointestinal Tract/immunology/*pathology ; Humans ; Immunoglobulin Heavy Chains/analysis ; Immunoglobulin Light Chains/analysis ; Kaplan-Meier Estimate ; Male ; Middle Aged ; Multivariate Analysis ; Predictive Value of Tests ; Prognosis ; Proportional Hazards Models ; Republic of Korea ; Retrospective Studies ; Risk Factors ; Serum Amyloid A Protein/analysis ; Time Factors