Clinical and Genetic Features of Korean Inherited Arrhythmia Probands

Background and Objectives@#Inherited arrhythmia (IA) is a more common cause of sudden cardiac death in Asian population, but little is known about the genetic background of Asian IA probands. We aimed to investigate the clinical characteristics and analyze the genetic underpinnings of IA in a Korean cohort. @*Methods@#This study was conducted in a multicenter cohort of the Korean IA Registry from 2014 to 2017. Genetic testing was performed using a next-generation sequencing panel including 174 causative genes of cardiovascular disease. @*Results@#Among the 265 IA probands, idiopathic ventricular fibrillation (IVF) and Brugada Syndrome (BrS) was the most prevalent diseases (96 and 95 cases respectively), followed by long QT syndrome (LQTS, n=54). Two-hundred-sixteen probands underwent genetic testing, and 69 probands (31.9%) were detected with genetic variant, with yield of pathogenic or likely pathogenic variant as 6.4%. Left ventricular ejection fraction was significantly lower in genotype positive probands (54.7±11.3 vs. 59.3±9.2%, p=0.005). IVF probands showed highest yield of positive genotype (54.0%), followed by LQTS (23.8%), and BrS (19.5%). @*Conclusions@#There were significant differences in clinical characteristics and genetic yields among BrS, LQTS, and IVF. Genetic testing did not provide better yield for BrS and LQTS. On the other hand, in IVF, genetic testing using multiple gene panel might enable the molecular diagnosis of concealed genotype, which may alter future clinical diagnosis and management strategies.

Impact of Positron Emission Tomography Viability Imaging:Guided Revascularizations on Clinical Outcomes in Patients With Myocardial Scar on Single-Photon Emission Computed Tomography Scans

Background@#Positron emission tomography (PET) viability scan is used to determine whether patients with a myocardial scar on single-photon emission computed tomography (SPECT) may need revascularization. However, the clinical utility of revascularization decision-making guided by PET viability imaging has not been proven yet. The purpose of this study was to investigate the impact of PET to determine revascularization on clinical outcomes. @*Methods@#Between September 2012 and May 2021, 53 patients (37 males; mean age = 64 ± 11 years) with a myocardial scar on MIBI SPECT who underwent PET viability test were analyzed in this study. The primary outcome was a temporal change in echocardiographic findings.The secondary outcome was all-cause mortality. @*Results@#Viable myocardium was presented by PET imaging in 29 (54.7%) patients.Revascularization was performed in 26 (49.1%) patients, including 18 (34.0%) with percutaneous coronary intervention (PCI) and 8 (15.1%) with coronary artery bypass grafting.There were significant improvements in echocardiographic findings in the revascularization group and the viable myocardium group. All-cause mortality was significantly lower in the revascularization group than in the medical therapy-alone group (19.2% vs. 44.4%, log-rank P = 0.002) irrespective of viable (21.4% vs. 46.7%, log-rank P = 0.025) or non-viable myocardium (16.7% vs. 41.7%, log-rank P = 0.046). All-cause mortality was significantly lower in the PCI group than in the medical therapy-alone group (11.1% vs. 44.4%, log-rank P < 0.001). @*Conclusion@#Revascularization improved left ventricular systolic function and survival of patients with a myocardial scar on SPECT scans, irrespective of myocardial viability on PET scans.

Impact of the COVID-19 Pandemic on Patient Delay and Clinical Outcomes for Patients With Acute Myocardial Infarction

Background@#It has been known that the fear of contagion during the coronavirus disease 2019 (COVID-19) creates time delays with subsequent impact on mortality in patients with acute myocardial infarction (AMI). However, difference of time delay and clinical outcome in patients with ST-segment elevation myocardial infarction (STEMI) or non-STEMI between the COVID-19 pandemic and pre-pandemic era has not been fully investigated yet in Korea. The aim of this study was to investigate the impact of COVID-19 pandemic on time delays and clinical outcome in patients with STEMI or non-STEMI compared to the same period years prior. @*Methods@#A total of 598 patients with STEMI (n = 195) or non-STEMI (n = 403) who underwent coronary angiography during the COVID-19 pandemic (February 1 to April 30, 2020) and prepandemic era (February 1 to April 30, 2017, 2018, and 2019) were analyzed in this study. Main outcomes were the incidence of time delay, cardiac arrest, and in-hospital death. @*Results@#There was 13.5% reduction in the number of patients hospitalized with AMI during the pandemic compared to pre-pandemic era. In patients with STEMI, door to balloon time tended to be longer during the pandemic compared to pre-pandemic era (55.7 ± 12.6 minutes vs. 60.8 ± 13.0 minutes, P = 0.08). There were no significant differences in cardiac arrest (15.6% vs. 10.4%, P = 0.397) and in-hospital mortality (15.6% vs. 10.4%, P = 0.397) between pre-pandemic and the pandemic era. In patients with non-STEMI, symptom to door time was significantly longer (310.0 ± 346.2 minutes vs. 511.5 ± 635.7 minutes, P = 0.038) and the incidence of cardiac arrest (0.9% vs. 3.5%, P = 0.017) and in-hospital mortality (0.3% vs.2.3%, P = 0.045) was significantly greater during the pandemic compared to pre-pandemic era. Among medications, angiotensin converting enzyme inhibitors/angiotensin type 2 receptor blockers (ACE-I/ARBs) were underused in STEMI (64.6% vs. 45.8%, P = 0.021) and non-STEMI (67.8% vs. 57.0%, P = 0.061) during the pandemic. @*Conclusion@#During the COVID-19 pandemic, there has been a considerable reduction in hospital admissions for AMI, time delay, and underuse of ACE-I/ARBs for the management of AMI, and this might be closely associated with the excess death in Korea.

Electrocardiographic Manifestations in Patients with COVID-19: Daegu in South Korea

Background and Objectives@#As the coronavirus disease 2019 (COVID-19) spreads worldwide, cardiac injury in patients infected with COVID-19 becomes a significant concern. Thus, this study investigates the impact of several electrocardiogram (ECG) parameters and disease severity in COVID-19 patients. @*Methods@#Seven medical centers in Daegu admitted 822 patients with COVID-19 between February and April 2020. This study examined 267 patients among them who underwent an ECG test and evaluated their biochemical parameters like C-reactive protein (CRP), log N-terminal pro-B-type Natriuretic Peptide (NT-proBNP), cardiac enzyme, and ECG parameters (heart rate, PR interval, QRS interval, T inversion, QT interval, and Tpe [the interval between peak to end in a T wave]). @*Results@#Those patients were divided into 3 groups of mild (100 patients), moderate (89 patients), and severe (78 patients) according to clinical severity score. The level of CRP, log NT-proBNP, and creatinine kinase-myocardial band were significantly increased in severe patients. Meanwhile, severe patients exhibited prolonged QT intervals (QTc) and Tpe (Tpe-c) compared to mild or moderate patients. Moreover, deceased patients (58; 21.7%) showed increased dispersion of QTc and Tpe-c compared with surviving patients (78.2±41.1 vs. 40.8±24.6 ms and 60.2±37.3 vs. 40.8±24.5 ms, both p<0.05, respectively). The QTc dispersion of more than 56.1 ms could predict the mortality in multivariate analysis (odd ratio, 11.55; 95% confidence interval, 3.746–42.306). @*Conclusions@#COVID-19 infections could involve cardiac injuries, especially cardiac repolarization abnormalities. A prolonged QTc dispersion could be an independent predictable factor of mortality.

Impact of Cardiovascular Risk Factors and Cardiovascular Diseases on Outcomes in Patients Hospitalized with COVID-19 in Daegu Metropolitan City

Background@#Data regarding the association between preexisting cardiovascular risk factors (CVRFs) and cardiovascular diseases (CVDs) and the outcomes of patients requiring hospitalization for coronavirus disease 2019 (COVID-19) are limited. Therefore, the aim of this study was to investigate the impact of preexisting CVRFs or CVDs on the outcomes of patients with COVID-19 hospitalized in a Korean healthcare system. @*Methods@#Patients with COVID-19 admitted to 10 hospitals in Daegu Metropolitan City, Korea, were examined. All sequentially hospitalized patients between February 15, 2020, and April 24, 2020, were enrolled in this study. All patients were confirmed to have COVID-19 based on the positive results on the polymerase chain reaction testing of nasopharyngeal samples. Clinical outcomes during hospitalization, such as requiring intensive care and invasive mechanical ventilation (MV) and death, were evaluated. Moreover, data on baseline comorbidities such as a history of diabetes, hypertension, dyslipidemia, current smoking, heart failure, coronary artery disease, cerebrovascular accidents, and other chronic cardiac diseases were obtained. @*Results@#Of all the patients enrolled, 954 (42.0%) had preexisting CVRFs or CVDs. Among the CVRFs, the most common were hypertension (28.8%) and diabetes mellitus (17.0%). The prevalence rates of preexisting CVRFs or CVDs increased with age (P < 0.001). The number of patients requiring intensive care (P < 0.001) and invasive MV (P < 0.001) increased with age.The in-hospital death rate increased with age (P < 0.001). Patients requiring intensive care (5.3% vs. 1.6%; P < 0.001) and invasive MV (4.3% vs. 1.7%; P < 0.001) were significantly greater in patients with preexisting CVRFs or CVDs. In-hospital mortality (12.9% vs. 3.1%; P < 0.001) was significantly higher in patients with preexisting CVRFs or CVDs. Among the CVRFs, diabetes mellitus and hypertension were associated with increased requirement of intensive care and invasive MV and in-hospital death. Among the known CVDs, coronary artery disease and congestive heart failure were associated with invasive MV and in-hospital death. In multivariate analysis, preexisting CVRFs or CVDs (odds ratio [OR], 1.79; 95% confidence interval [CI], 1.07–3.01; P = 0.027) were independent predictors of in-hospital death adjusting for confounding variables. Among individual preexisting CVRF or CVD components, diabetes mellitus (OR, 2.43; 95% CI, 1.51–3.90; P < 0.001) and congestive heart failure (OR, 2.43; 95% CI, 1.06–5.87; P = 0.049) were independent predictors of in-hospital death. @*Conclusion@#Based on the findings of this study, the patients with confirmed COVID-19 with preexisting CVRFs or CVDs had worse clinical outcomes. Caution is required in dealing with these patients at triage.after

Electrocardiographic Manifestations in Patients with COVID-19: Daegu in South Korea

Background and Objectives@#As the coronavirus disease 2019 (COVID-19) spreads worldwide, cardiac injury in patients infected with COVID-19 becomes a significant concern. Thus, this study investigates the impact of several electrocardiogram (ECG) parameters and disease severity in COVID-19 patients. @*Methods@#Seven medical centers in Daegu admitted 822 patients with COVID-19 between February and April 2020. This study examined 267 patients among them who underwent an ECG test and evaluated their biochemical parameters like C-reactive protein (CRP), log N-terminal pro-B-type Natriuretic Peptide (NT-proBNP), cardiac enzyme, and ECG parameters (heart rate, PR interval, QRS interval, T inversion, QT interval, and Tpe [the interval between peak to end in a T wave]). @*Results@#Those patients were divided into 3 groups of mild (100 patients), moderate (89 patients), and severe (78 patients) according to clinical severity score. The level of CRP, log NT-proBNP, and creatinine kinase-myocardial band were significantly increased in severe patients. Meanwhile, severe patients exhibited prolonged QT intervals (QTc) and Tpe (Tpe-c) compared to mild or moderate patients. Moreover, deceased patients (58; 21.7%) showed increased dispersion of QTc and Tpe-c compared with surviving patients (78.2±41.1 vs. 40.8±24.6 ms and 60.2±37.3 vs. 40.8±24.5 ms, both p<0.05, respectively). The QTc dispersion of more than 56.1 ms could predict the mortality in multivariate analysis (odd ratio, 11.55; 95% confidence interval, 3.746–42.306). @*Conclusions@#COVID-19 infections could involve cardiac injuries, especially cardiac repolarization abnormalities. A prolonged QTc dispersion could be an independent predictable factor of mortality.

Perioperative outcomes of interrupted anticoagulation in patients with non-valvular atrial fibrillation undergoing non-cardiac surgery / 영남의대학술지

Background@#This study aimed to investigate the incidences of and risk factors for perioperative events following anticoagulant discontinuation in patients with non-valvular atrial fibrillation (NVAF) undergoing non-cardiac surgery. @*Methods@#A total of 216 consecutive patients who underwent cardiac consultation for suspending perioperative anticoagulants were enrolled. A perioperative event was defined as a composite of thromboembolism and major bleeding. @*Results@#The mean anticoagulant discontinuation duration was 5.7 (±4.2) days and was significantly longer in the warfarin group (p<0.001). Four perioperative thromboembolic (1.85%; three strokes and one systemic embolization) and three major bleeding events (1.39%) were observed. The high CHA2DS2-VASc and HAS-BLED scores and a prolonged preoperative anticoagulant discontinuation duration (4.4±2.1 vs. 2.9±1.8 days; p=0.028) were associated with perioperative events, whereas the anticoagulant type (non-vitamin K antagonist oral anticoagulants or warfarin) was not. The best cut-off levels of the HAS-BLED and CHA2DS2-VASc scores were 3.5 and 2.5, respectively, and the preoperative anticoagulant discontinuation duration for predicting perioperative events was 2.5 days. Significant differences in the perioperative event rates were observed among the four risk groups categorized according to the sum of these values: risk 0, 0%; risk 1, 0%; risk 2, 5.9%; and risk 3, 50.0% (p<0.001). Multivariate logistic regression analysis showed that the HAS-BLED score was an independent predictor for perioperative events. @*Conclusion@#Thromboembolic events and major bleeding are not uncommon during perioperative anticoagulant discontinuation in patients with NVAF, and interrupted anticoagulation strategies are needed to minimize these.

Incremental Predictive Value of Plasma Renin Activity as a Prognostic Biomarker in Patients with Heart Failure

Background@#The association of N-terminal pro-B type natriuretic peptide (NT-proBNP) and plasma renin activity (PRA) for the prognosis of the patients with acute heart failure (HF) has not been fully investigated. This study aimed to determine the association between NT-proBNP and PRA and to investigate the incremental value of PRA to NT-proBNP for predicting long term prognosis in patients with acute HF. @*Methods@#Three hundred and ninety-six patients (mean age, 64.7 ± 15.9 years; 46.5% female) presenting with acute HF were enrolled between December 2004 and July 2013. Patients with newly diagnosed HF as well as patients with acute exacerbated chronic HF were included. The prognosis was assessed with the composite event of all-cause mortality and readmission for HF during a 2-year follow-up period. @*Results@#The etiology of HF was ischemic in 116 (29.3%) patients. In a Cox proportional hazards model, log-transformed PRA (hazard ratio [HR], 1.205; P = 0.007) was an independent predictor of the composite outcome of all-cause mortality and readmission for HF in addition to age (HR, 1.032; P = 0.001), white blood cell (WBC) count (HR, 1.103;P< 0.001), and left ventricular ejection fraction (LVEF) (HR, 0.978; P = 0.013). Adding PRA to age, sex, LVEF, and NT-proBNP significantly improved the prediction for the composite outcome of all-cause mortality and readmission for HF, as shown by the net reclassification improvement (0.47; P < 0.001) and integrated discrimination improvement (0.10; P < 0.001). @*Conclusion@#PRA could provide incremental predictive value to NT-proBNP for predicting long term prognosis in patients with acute HF.

A Case of COVID-19 with Acute Myocardial Infarction and Cardiogenic Shock

A 60-year-old male patient with coronavirus disease-2019 showed new onset ST-segment elevation in V1–V2 leads on electrocardiogram and cardiac enzyme elevation in intensive care unit. He had a history of type 2 diabetes mellitus, hypertension, and dyslipidemia. He was receiving mechanical ventilation and veno-venous extracorporeal membrane oxygenation treatment for severe hypoxia. Two-D echocardiogram showed regional wall motion abnormalities. We performed primary percutaneous coronary intervention for acute myocardial infarction complicating cardiogenic shock under hemodynamic support. He expired on the 16th day of admission because of cardiogenic shock and multi-organ failure. Active surveillance and intensive treatment strategy are important for saving lives of COVID-19 patients with acute myocardial infarction.

Clinical Impact of Implantable Cardioverter-Defibrillator Therapy and Mortality Prediction Model for Effective Primary Prevention in Korean Patients

BACKGROUND: Studies on the efficacy of implantable cardioverter-defibrillator (ICD) therapy for primary prevention in Asian patients are relatively lacking compared to those for secondary prevention. Also, it is important to stratify which patients will benefit from ICD therapy for primary prevention.METHODS: Of 483 consecutive patients who received new implantation of ICD in 9 centers in Korea, 305 patients with reduced left ventricular systolic function and/or documented ventricular fibrillation/tachycardia were enrolled and divided into primary (n = 167) and secondary prevention groups (n = 138).RESULTS: During mean follow-up duration of 2.6 ± 1.6 years, appropriate ICD therapy occurred in 78 patients (25.6%), and appropriate ICD shock and anti-tachycardia pacing occurred in 15.1% and 15.1% of patients, respectively. Appropriate ICD shock rate was not different between the two groups (primary 12% vs. secondary 18.8%, P = 0.118). However, appropriate ICD therapy rate including shock and anti-tachycardia pacing was significantly higher (primary 18% vs. secondary 34.8%, P = 0.001) in the secondary prevention group. Type of prevention and etiology, appropriate and inappropriate ICD shock did not affect all-cause death. High levels of N-terminal pro-B-type natriuretic peptide, New York Heart Association functional class, low levels of estimated glomerular filtration ratio, and body mass index were associated with death before appropriate ICD shock in the primary prevention group. When patients were categorized in 5 risk score groups according to the sum of values defined by each cut-off level, significant differences in death rate before appropriate ICD shock were observed among risk 0 (0%), 1 (3.6%), 2 (3%), 3 (26.5%), and 4 (40%) (P < 0.001).CONCLUSION: In this multicenter regional registry, the frequency of appropriate ICD therapy is not low in the primary prevention group. In addition, combination of poor prognostic factors of heart failure is useful in risk stratification of patients who are not benefiting from ICD therapy for primary prevention.

Clinical Impact of Implantable Cardioverter-Defibrillator Therapy and Mortality Prediction Model for Effective Primary Prevention in Korean Patients

BACKGROUND@#Studies on the efficacy of implantable cardioverter-defibrillator (ICD) therapy for primary prevention in Asian patients are relatively lacking compared to those for secondary prevention. Also, it is important to stratify which patients will benefit from ICD therapy for primary prevention.@*METHODS@#Of 483 consecutive patients who received new implantation of ICD in 9 centers in Korea, 305 patients with reduced left ventricular systolic function and/or documented ventricular fibrillation/tachycardia were enrolled and divided into primary (n = 167) and secondary prevention groups (n = 138).@*RESULTS@#During mean follow-up duration of 2.6 ± 1.6 years, appropriate ICD therapy occurred in 78 patients (25.6%), and appropriate ICD shock and anti-tachycardia pacing occurred in 15.1% and 15.1% of patients, respectively. Appropriate ICD shock rate was not different between the two groups (primary 12% vs. secondary 18.8%, P = 0.118). However, appropriate ICD therapy rate including shock and anti-tachycardia pacing was significantly higher (primary 18% vs. secondary 34.8%, P = 0.001) in the secondary prevention group. Type of prevention and etiology, appropriate and inappropriate ICD shock did not affect all-cause death. High levels of N-terminal pro-B-type natriuretic peptide, New York Heart Association functional class, low levels of estimated glomerular filtration ratio, and body mass index were associated with death before appropriate ICD shock in the primary prevention group. When patients were categorized in 5 risk score groups according to the sum of values defined by each cut-off level, significant differences in death rate before appropriate ICD shock were observed among risk 0 (0%), 1 (3.6%), 2 (3%), 3 (26.5%), and 4 (40%) (P < 0.001).@*CONCLUSION@#In this multicenter regional registry, the frequency of appropriate ICD therapy is not low in the primary prevention group. In addition, combination of poor prognostic factors of heart failure is useful in risk stratification of patients who are not benefiting from ICD therapy for primary prevention.

Clinical Impact of Implantable Cardioverter-Defibrillator Therapy and Mortality Prediction Model for Effective Primary Prevention in Korean Patients

BACKGROUND@#Studies on the efficacy of implantable cardioverter-defibrillator (ICD) therapy for primary prevention in Asian patients are relatively lacking compared to those for secondary prevention. Also, it is important to stratify which patients will benefit from ICD therapy for primary prevention.@*METHODS@#Of 483 consecutive patients who received new implantation of ICD in 9 centers in Korea, 305 patients with reduced left ventricular systolic function and/or documented ventricular fibrillation/tachycardia were enrolled and divided into primary (n = 167) and secondary prevention groups (n = 138).@*RESULTS@#During mean follow-up duration of 2.6 ± 1.6 years, appropriate ICD therapy occurred in 78 patients (25.6%), and appropriate ICD shock and anti-tachycardia pacing occurred in 15.1% and 15.1% of patients, respectively. Appropriate ICD shock rate was not different between the two groups (primary 12% vs. secondary 18.8%, P = 0.118). However, appropriate ICD therapy rate including shock and anti-tachycardia pacing was significantly higher (primary 18% vs. secondary 34.8%, P = 0.001) in the secondary prevention group. Type of prevention and etiology, appropriate and inappropriate ICD shock did not affect all-cause death. High levels of N-terminal pro-B-type natriuretic peptide, New York Heart Association functional class, low levels of estimated glomerular filtration ratio, and body mass index were associated with death before appropriate ICD shock in the primary prevention group. When patients were categorized in 5 risk score groups according to the sum of values defined by each cut-off level, significant differences in death rate before appropriate ICD shock were observed among risk 0 (0%), 1 (3.6%), 2 (3%), 3 (26.5%), and 4 (40%) (P < 0.001).@*CONCLUSION@#In this multicenter regional registry, the frequency of appropriate ICD therapy is not low in the primary prevention group. In addition, combination of poor prognostic factors of heart failure is useful in risk stratification of patients who are not benefiting from ICD therapy for primary prevention.

Serum levels of carbohydrate antigen 125 in combination with N-terminal pro-brain natriuretic peptide in patients with acute decompensated heart failure

BACKGROUND/AIMS@#Carbohydrate antigen 125 (CA-125) is an emerging prognostic biomarker for heart failure. We aimed to test the long-term prognostic value of CA-125 in combination with N-terminal pro-brain natriuretic peptide (NT-proBNP) in patients with acute decompensated heart failure (ADHF).@*METHODS@#This observational study included a total of 413 patients (64.1 ± 15.6 year-old, 214 men) with ADHF. All-cause mortality during the 2-year follow-up was investigated for the prognosis.@*RESULTS@#During the follow-up (mean follow-up, 591 ± 233 days), 109 deaths (26.0%) were recorded. In the multivariable analysis model, CA-125 was an independent factor associated with all-cause mortality (log CA-125: hazard ratio, 1.23; 95% confidence interval, 1.02 to 1.48; p = 0.030) together with age, sex, New York Heart Association class, β-blocker, and NT-proBNP. The Kaplan-Meier survival analysis demonstrated that the group with both low marker levels showed the best 2-year survival (87.9%) followed by the group with low NT-proBNP and high CA-125 (76.1%), high NT-proBNP and low CA-125 (64.7%) and high NT-proBNP and high CA-125 levels (54.3%) (p < 0.001). Addition of CA-125 in combination with NT-proBNP and established risk factors further increased the predictive power for mortality in patients with ADHF.@*CONCLUSIONS@#CA-125 was an independent factor associated with all-cause mortality in patients with ADHF. Combination of CA-125 with NT-proBNP significantly improved the prediction of mortality in patients with ADHF.

2018 KHRS Guidelines for Catheter Ablation of Ventricular Arrhythmias: Part 1

Ventricular arrhythmias (VA) are a major cause of sudden cardiac death (SCD) in patients with known heart disease. Risk assessment and effective prevention of SCD are key issues in these patients. Implantable cardioverter defibrillator (ICD) insertion effectively treats sustained VA and reduces mortality in patients at high risk of SCD. Appropriate anti-arrhythmic drugs and catheter ablation reduce the VA burden and the occurrence of ICD shocks. In this guideline, authors have described the general examination and medical treatment of patients with VA. Medications and catheter ablation are also used as acute phase therapy for sustained VA.

2018 KHRS Guidelines for Catheter Ablation of Ventricular Arrhythmias: Part 2

The recommendations outlined constitute the first clinical practice guidelines of the Korean Heart Rhythm Society regarding catheter ablation of ventricular arrhythmias (VA). This is a guideline PART 2, which includes VA in the structurally normal heart, inherited primary arrhythmia syndromes, VA related to congenital heart disease, as well as VA and sudden cardiac death observed in specific populations. In the structurally normal heart, treatment is guided by the occurrence of symptoms or the frequency of arrhythmias that cause ventricular dysfunction over time. Catheter ablation can be recommended in patients in whom anti-arrhythmic medications are ineffective. The sites of origin of arrhythmic activity are known to be the outflow tract, fascicles, papillary muscle, or the annulus. Specific cardiac channelopathies include congenital long QT and Brugada syndrome. This guideline discusses the diagnostic criteria, risk stratification, and treatment of these syndromes. We have included recommendations for adult congenital heart disease. Moreover, we have discussed the management of VA occurring in specific populations such as in patients with psychiatric and neurological disorders, pregnant patients, those with obstructive sleep apnea or drug-related pro-arrhythmias, athletes, and elderly patients.

2018 KHRS Guidelines for Catheter Ablation of Ventricular Arrhythmias: Part 3

Treatment of ventricular arrhythmias (VA) usually involves managing the underlying cardiac conditions that cause the arrhythmia. However, managing the underlying disease is often challenging, and catheter ablation, or treatment targeting the VA itself might be required in a few patients. In this article, we explored evidence and recommendations regarding the treatment of VA in patients with structural heart disease focusing on the utilization of catheter ablation in these patients. The administration of optimal medical therapy, insertion of an implantable cardioverter-defibrillator, or resynchronization therapy improves survival in patients with left ventricular dysfunction. The role of catheter ablation in preventing sudden cardiac death remains uncertain in this population. In patients with coronary artery disease, reversing myocardial ischemia via revascularization is important in managing VA. Catheter ablation is recommended in patients with recurrent ventricular tachycardia in a setting of ischemic heart disease. In patients with non-ischemic cardiomyopathies such as dilated cardiomyopathy or hypertrophic cardiomyopathy, catheter ablation may be considered for those presenting with drug-refractory ventricular tachycardia.

Effectiveness of Implantable Cardioverter-Defibrillator Therapy for Heart Failure Patients according to Ischemic or Non-Ischemic Etiology in Korea

BACKGROUND AND OBJECTIVES: This study was performed to describe clinical characteristics of patients with left ventriculars (LV) dysfunction and implantable cardioverter-defibrillator (ICD), and to evaluate the effect of ICD therapy on survival in Yeongnam province of Korea. SUBJECTS AND METHODS: From a community-based device registry (9 centers, Yeongnam province, from November 1999 to September 2012), 146 patients with LV dysfunction and an ICD implanted for primary or secondary prophylaxis, were analyzed. The patients were divided into two groups, based on the etiology (73 with ischemic cardiomyopathy and 73 with non-ischemic cardiomyopathy), and indication for the device implantation (36 for primary prevention and 110 for secondary prevention). The cumulative first shock rate, all cause death, and type and mode of death, were determined according to the etiology and indication. RESULTS: Over a mean follow-up of 3.5 years, the overall ICD shock rate was about 39.0%. ICD shock therapy was significantly more frequent in the secondary prevention group (46.4% vs. 16.7%, p=0.002). The cumulative probability of a first appropriate shock was higher in the secondary prevention group (p=0.015). There was no significant difference in the all-cause death, cardiac death, and mode of death between the groups according to the etiology and indication. CONCLUSION: Studies from this multicenter regional registry data shows that in both ischemic and non-ischemic cardiomyopathy patients, the ICD shock therapy rate was higher in the secondary prevention group than primary prevention group.

Optimal International Normalized Ratio for Warfarin Therapy in Elderly Korean Patients with Non-Valvular Atrial Fibrillation

BACKGROUND AND OBJECTIVES: Optimal international normalized ratio (INR) in elderly atrial fibrillation (AF) patients at higher risk of hemorrhagic events remains unclear. We investigated the efficacy and safety of low-intensity warfarin therapy (target international normalized ratio [INR], 1.6-2.6) in elderly Korean patients with nonvalvular AF (NVAF). SUBJECTS AND METHODS: We enrolled 528 NVAF patients (mean age, 67±9 years; 361 men) who were actively taking warfarin. Major events were defined based on the annual rates of ischemic stroke, systemic embolism, and major bleeding events requiring blood transfusion or hospitalization. Time in therapeutic range (TTR) was 45±19% for all patients. RESULTS: Ischemic stroke and systemic embolism occurred in 20 patients with INR between 1.00 and 2.44 (16 ischemic strokes and 4 systemic embolisms) and major bleeding in 37 patients with INR between 1.74 and no coagulation (exceed laboratory detection capability, more than 10 [7 intracranial hemorrhages, 21 gastrointestinal bleedings, and 9 others]). Incidence rates of ischemic or hemorrhagic events at INR3 were 3.0%, 1.4%, and 20.1% per year, respectively. In patients who were ≥70 years old, CHADS₂, CHA₂DS₂VASc, and HAS-BLED scores were significantly higher compared with those in patients who were <70 years old. When we applied the INR between 1.6 and 2.6, as recommended by the Japanese AF Guideline for patients≥70 years old, the TTR increased from 43.8% to 58.6%. In addition, ischemic or hemorrhagic event rates decreased from 1.9% to 1.2% within the optimal INR range. CONCLUSION: Low-intensity warfarin therapy (INR, 1.6-2.6) should be considered in elderly Korean patients with NVAF.

Genetic Variation of SCN5A in Korean Patients with Sick Sinus Syndrome

BACKGROUND AND OBJECTIVES: Due to recent studies that have shown an association between the genetic variation of SCN5A and sick sinus syndrome (SSS), we sought to determine if a similar correlation existed in Korean patients with SSS. SUBJECTS AND METHODS: We enrolled 30 patients with SSS who showed a sinus pause (longer than 3.0 s) in Holter monitoring, in addition to 80 controls. All exons including the putative splicing sites of the SCN5A gene were amplified by polymerase chain reaction and sequenced either directly or following subcloning. Wild-type and single nucleotide polymorphisms were expressed in human embryonic kidney cells, and the peak sodium current (I(Na)) was analyzed using the whole-cell patch-clamp technique. RESULTS: A total of 9 genetic variations were identified: 7 variations (G87A-A29A, IVS9-3C>A, A1673G-H558R, G3823A-D1275N, T5457C-D1819D, T5963G-L1988R, and C5129T-S1710L) had been previously reported, and 2 variants (A3075T-E1025D and T4847A-F1616Y) were novel; the potential structural effects of F1616Y were analyzed in a three-dimensional model of the SCN5A domain. Patch-clamp studies at room temperature demonstrated that the peak I(Na) was significantly increased by 140% in HEK cells transfected with F1616Y compared with wild-type (-335.13 pA/pF+/-24.04, n=8 vs. -139.95 pA/pF+/-23.76, n=7, respectively). Furthermore, the voltage dependency of the activation and steady-state inactivation of F1616Y were leftward-shifted compared with wild-type (V(h) activation=-55.36 mv+/-0.22, n=8 vs. V(h) activation=-44.21 mV+/-0.17, n=7; respectively; V(h) inactivation=-104.47 mV+/-0.21, n=7 vs. V(h) inactivation=-84.89 mV+/-0.09, n=12, respectively). CONCLUSION: F1616Y may be associated with SSS.

Angiotensin II type 1 receptor blockers as a first choice in patients with acute myocardial infarction

BACKGROUND/AIMS: Angiotensin II type 1 receptor blockers (ARBs) have not been adequately evaluated in patients without left ventricular (LV) dysfunction or heart failure after acute myocardial infarction (AMI). METHODS: Between November 2005 and January 2008, 6,781 patients who were not receiving angiotensin-converting enzyme inhibitors (ACEIs) or ARBs were selected from the Korean AMI Registry. The primary endpoints were 12-month major adverse cardiac events (MACEs) including death and recurrent AMI. RESULTS: Seventy percent of the patients were Killip class 1 and had a LV ejection fraction > or = 40%. The prescription rate of ARBs was 12.2%. For each patient, a propensity score, indicating the likelihood of using ARBs during hospitalization or at discharge, was calculated using a non-parsimonious multivariable logistic regression model, and was used to match the patients 1:4, yielding 715 ARB users versus 2,860 ACEI users. The effect of ARBs on in-hospital mortality and 12-month MACE occurrence was assessed using matched logistic and Cox regression models. Compared with ACEIs, ARBs significantly reduced in-hospital mortality(1.3% vs. 3.3%; hazard ratio [HR], 0.379; 95% confidence interval [CI], 0.190 to0.756; p = 0.006) and 12-month MACE occurrence (4.6% vs. 6.9%; HR, 0.661; 95% CI, 0.457 to 0.956; p = 0.028). However, the benefit of ARBs on 12-month mortality compared with ACEIs was marginal (4.3% vs. 6.2%; HR, 0.684; 95% CI, 0.467 to 1.002; p = 0.051). CONCLUSIONS: Our results suggest that ARBs are not inferior to, and may actually be better than ACEIs in Korean patients with AMI.