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Hyungseop Kim - Top 30 Publications

Normal reference values of diastolic strain rate in healthy individuals: Chronological trends and the comparison according to genders.

Recently, the diastolic strain rate (DSR) utilizing speckle-tracking echocardiography has been proposed as a novel parameter for left ventricular diastolic function. We aimed to present normal reference data for those in a large-sized, selected group of healthy individuals.

Diagnosis, Treatment, and Prevention of Cardiovascular Toxicity Related to Anti-Cancer Treatment in Clinical Practice: An Opinion Paper from the Working Group on Cardio-Oncology of the Korean Society of Echocardiography.

Cardiovascular (CV) toxicity associated with anti-cancer treatment is commonly encountered and raises critical problems that often result in serious morbidity or mortality. Most cardiac toxicities are related to the cumulative dose of chemotherapy; however, the type of chemotherapy, concomitant agents, and/or conventional CV risk factors have been frequently implicated in CV toxicity. Approximately half of the patients exhibiting CV toxicity receive an anthracycline-based regimen. Therefore, serologic biomarkers or cardiac imagings are important during anti-cancer treatment for early detection and the decision of appropriate management of cardiotoxicity. However, given the difficulty in determining a causal relationship, a multidisciplinary collaborative approach between cardiologists and oncologists is required. In this review, we summarize the CV toxicity and focus on the role of cardiac imaging in management strategies for cardiotoxicity associated with anti-cancer treatment.

Prognostic Usefulness of Tricuspid Annular Diameter for Cardiovascular Events in Patients With Tricuspid Regurgitation of Moderate to Severe Degree.

Functional tricuspid regurgitation (TR) is frequently encountered. Current guidelines recommend the surgical correction of severe TR only at the time of left valve surgery despite emphasizing the enlarged tricuspid annulus (TA) dimension. We attempted to evaluate the relation between TA dimension and clinical outcomes of moderate or severe TR. A total of 213 patients (mean age 68 years, women 68%) with moderate or severe TR secondary to left-sided valve surgery, nonvalvular disease, or isolated primary TR were retrospectively identified and classified into tertiles of TA dimension. Cardiovascular (CV) outcomes were defined as a composite of hospitalization for worsening heart failure (HF), stroke, and CV death over a median follow-up of 3.4 years. Upper and lower tertiles of TA dimension had high frequencies of left-sided valve surgery and isolated primary TR, respectively. TA dimension was correlated with TR severity assigned as color Doppler grade and systolic tissue Doppler imaging of the tricuspid valve (TDI s'). During follow-up, there were 87 (41%) occurrences of primary outcomes: 65 HFs (31%), 13 CV deaths (6%), and 9 strokes (4%). There was a high frequency of adverse outcomes in the upper tertile. TA dimension and TDI s' were independently related to outcomes. An enlarged TA dimension was associated with outcomes irrespective of subgroups according to type or severity of TR and TDI s' (p = 0.21, p = 0.77, p = 0.15 for interaction). A cut-off value of 4.0 cm for TA dimension was best for CV event occurrence. When assessing clinical CV outcomes, TA dimension should be considered, even in moderate TR.

Implications of prescribing a fixed-dose combination in clinical cardiology practice: a retrospective observational study using a single medical centre database in Korea.

Fixed-dose combination (FDC) prescribing enhances adherence to medication. However, there are limited data regarding the usefulness of FDC drugs across different risk groups. The aim of this study was to explore the relationship between FDC discontinuation and clinical outcomes.

Heart rate at first postdischarge visit and outcomes in patients with heart failure.

Heart rate control is important to prevent adverse outcomes in patients with heart failure (HF). However, postdischarge activity may worsen heart rate control, resulting in readmission. This study aimed to explore the implications of the heart rate differences between discharge and the first outpatient visit (D-O diff).

Evaluation of the impact of statin therapy on the obesity paradox in patients with acute myocardial infarction: A propensity score matching analysis from the Korea Acute Myocardial Infarction Registry.

The phenomenon of obesity paradox after acute myocardial infarction (AMI) has been reported under strong recommendation of statin therapy. However, the impact of statin therapy on this paradox has not been investigated. This study investigated the impact of statin therapy on 1-year mortality according to obesity after AMI. A total of 2745 AMI patients were included from the Korea Acute Myocardial Infarction Registry after 1:4 propensity score matching analysis (n = 549 for nonstatin group and n = 2196 for statin group). Primary and secondary outcomes were all-cause and cardiac death, respectively. During 1-year follow-up, the incidence of all-cause (8.4% vs 3.7%) and cardiac (6.2% vs 2.3%) death was higher in nonstatin group than in statin (P < .001, respectively). In nonstatin group, the incidence of all-cause (7.2% vs 9.0%) and cardiac (5.5% vs 6.5%) death did not differ significantly between obese and nonobese patients. However, in statin group, obese patients had lower 1-year rate of all-cause (1.7% vs 4.8%) and cardiac (1.2% vs 2.9%) death (P < .05, respectively), and lower cumulative rates by Kaplan-Meier analysis of all-cause and cardiac death compared with nonobese patients (log-rank P < .05, respectively). The overall risk of all-cause death was significantly lower in obese than in nonobese patients only in statin group (hazard ratio: 0.35; P = .001). After adjusting for confounding factors, obesity was independently associated with decreased risk of all-cause death in statin group. In conclusion, the greater benefit of statin therapy for survival in obese patients is further confirmation of the obesity paradox after AMI.

Normal 2-Dimensional Strain Values of the Left Ventricle: A Substudy of the Normal Echocardiographic Measurements in Korean Population Study.

It is important to understand the distribution of 2-dimensional strain values in normal population. We performed a multicenter trial to measure normal echocardiographic values in the Korean population.

Clinical Outcomes in Patients with Deferred Coronary Lesions according to Disease Severity Assessed by Fractional Flow Reserve.

Data on the clinical outcomes in deferred coronary lesions according to functional severity have been limited. This study evaluated the clinical outcomes of deferred lesions according to fractional flow reserve (FFR) grade using Korean FFR registry data. Among 1,294 patients and 1,628 lesions in Korean FFR registry, 665 patients with 781 deferred lesions were included in this study. All participants were consecutively categorized into 4 groups according to FFR; group 1: ≥ 0.96 (n = 56), group 2: 0.86-0.95 (n = 330), group 3: 0.81-0.85 (n = 170), and group 4: ≤ 0.80 (n = 99). Primary endpoint was major adverse cardiac events (MACE), a composite of all-cause death, myocardial infarction, and target vessel revascularization. The median follow-up period was 2.1 years. During follow-up, the incidence of MACE in groups 1-4 was 1.8%, 7.6%, 8.8%, and 13.1%, respectively. Compared to group 1, the cumulative rate by Kaplan-Meier analysis of MACE was not different for groups 2 and 3. However, group 4 had higher cumulative rate of MACE compared to group 1 (log-rank P = 0.013). In the multivariate Cox hazard models, only FFR (hazard ratio [HR], 0.95; P = 0.005) was independently associated with MACE among all participants. In contrast, previous history of percutaneous coronary intervention (HR, 2.37; P = 0.023) and diagnosis of acute coronary syndrome (ACS) (HR, 2.35; P = 0.015), but not FFR, were independent predictors for MACE in subjects with non-ischemic (FFR ≥ 0.81) deferred coronary lesions. Compared to subjects with ischemic deferred lesions, clinical outcomes in subjects with non-ischemic deferred lesions according to functional severity are favorable. However, longer-term follow-up may be necessary.

A comparison of echocardiographic variables of right ventricular function with exercise capacity after bosentan treatment in patients with pulmonary arterial hypertension: Results from a multicenter, prospective, cohort study.

Bosentan reduces pulmonary arterial pressure and improves exercise capacity in patients with pulmonary arterial hypertension (PAH). However, there are limited data regarding the extent to which the changes in echocardiographic variables reflect improvements in exercise capacity. We aimed to assess the improvement of echocardiographic variables and exercise capacity after 6 months of bosentan treatment for PAH.

The potential of cystatin-C to evaluate the prognosis of acute heart failure: A comparative study.

The prognosis of acute heart failure (HF) can be determined by cardio-renal function which is assessed by cystatin-C (Cys-C). We evaluated whether Cys-C could be a more useful prognostic indicator in acute HF, compared with uric acid (UA) and N-terminal pro-B-type natriuretic peptide (NT-proBNP).

Discrepancy between frequency domain optical coherence tomography and intravascular ultrasound in human coronary arteries and in a phantom in vitro coronary model.

This purpose of this study is to evaluate, concomitantly with quantitative coronary angiography (QCA), the potential discrepancy between frequency domain optical coherence tomography (FD-OCT) and intravascular ultrasound (IVUS) measurements in a phantom coronary model and in human coronary arteries within and outside stented segments.

Normal Echocardiographic Measurements in a Korean Population Study: Part II. Doppler and Tissue Doppler Imaging.

Hemodynamic and functional evaluation with Doppler and tissue Doppler study as a part of comprehensive echocardiography is essential but normal reference values have never been reported from Korean normal population especially according to age and sex.

Significance of apical cavity obliteration in apical hypertrophic cardiomyopathy.

Apical hypertrophic cardiomyopathy (HCM) is characterised by apical systolic obliteration and is associated with atrial fibrillation (AF), stroke, heart failure (HF), and mortality. We investigated whether apical obliteration of the left ventricular (LV) cavity could have an unfavourable impact on the clinical course of apical HCM.

Usefulness of Frequency Domain Optical Coherence Tomography Compared with Intravascular Ultrasound as a Guidance for Percutaneous Coronary Intervention.

To compare outcomes and rates of optimal stent placement between optical coherence tomography (OCT) and intravascular ultrasound (IVUS) guided percutaneous coronary intervention (PCI).

Normal Echocardiographic Measurements in a Korean Population Study: Part I. Cardiac Chamber and Great Artery Evaluation.

Measurement of the cardiac chamber is essential, and current guidelines recommend measuring and reporting values for both sides of the cardiac chamber during echocardiographic evaluation. Normal echocardiographic reference values have been suggested previously, but detailed information about right-sided chambers and values according to gender was not included.

Detecting masked high blood pressure in high-risk patients.

Atrial septal defect with normal pulmonary arterial pressure in adult cyanotic patient.

A 22-year-old male presented with recurrent stroke, central cyanosis, and dyspnea. Transesophageal echocardiography and cardiac catheterization revealed bidirectional shunt flow through atrial septal defect (ASD) without pulmonary arterial hypertension. The orifice of inferior vena cava facing towards ASD opening led partially right to left shunt resulting in cyanosis with normal pulmonary arterial pressure.

Characteristics of function-anatomy mismatch in patients with coronary artery disease.

Coronary lesions with mismatched functional and anatomical significance are not uncommon. We assessed the accuracy and predictors of mismatch between fractional flow reserve (FFR) and quantitative coronary angiography (QCA) analyses in patients with coronary lesions.

Long-term outcomes of simple crossover stenting from the left main to the left anterior descending coronary artery.

Although complex bifurcation stenting in patients with non-left main (LM) bifurcation lesions has not yielded better clinical outcomes than simpler procedures, the utility of complex bifurcation stenting to treat LM bifurcation lesions has not yet been adequately explored.

Three-dimensional echocardiographic reconstruction of double-orifice mitral valve and mitral leaflet prolapse.

Association between Doppler flow of atrial fibrillatory contraction and recurrence of atrial fibrillation after electrical cardioversion.

Left atrial fibrillatory contraction (Afc) flow can be frequently observed interspersed between two successive mitral E waves in patients with atrial fibrillation (AF). The aim of this study was to test the hypothesis that Afc is related to the maintenance of sinus rhythm after electrical cardioversion for AF.

Improved severe hepatopulmonary syndrome after liver transplantation in an adolescent with end-stage liver disease secondary to biliary atresia.

Hepatopulmonary syndrome (HPS) is a serious complication of end-stage liver disease, which is characterized by hypoxia, intrapulmonary vascular dilatation, and liver cirrhosis. Liver transplantation (LT) is the only curative treatment modality for patients with HPS. However, morbidity and mortality after LT, especially in cases of severe HPS, remain high. This case report describes a patient with typical findings of an extracardiac pulmonary arteriovenous shunt on contrast-enhanced transesophageal echocardiography (TEE), and clubbing fingers, who had complete correction of HPS by deceased donor LT. The patient was a 16-year-old female who was born with biliary atresia and underwent porto-enterostomy on the 55th day after birth. She had been suffered from progressive liver failure with dyspnea, clubbing fingers, and cyanosis. Preoperative arterial blood gas analysis revealed severe hypoxia (arterial O2 tension of 54.5 mmHg and O2 saturation of 84.2%). Contrast-enhanced TEE revealed an extracardiac right-to-left shunt, which suggested an intrapulmonary arteriovenous shunt. The patient recovered successfully after LT, not only with respect to physical parameters but also for pychosocial activity, including school performance, during the 30-month follow-up period.

Efficacy and safety of antiplatelet-combination therapy after drug-eluting stent implantation.

Combination single-pill therapy can improve cost-effectiveness in a typical medical therapy. However, there is a little evidence about the efficacy and tolerability of combination single-pill antiplatelet therapy after percutaneous coronary intervention (PCI) with drug-eluting stents (DES).

Left ventricular twist and ventricular-arterial coupling in hypertensive patients.

Left ventricular (LV) twist is usually influenced by LV hypertrophy resulting from hypertension or vascular stiffness. Vascular stiffness would increase arterial elastance (Ea), whereas LV end-systolic stiffness (Ees) could be influenced by LV hypertrophy. Therefore, in hypertensive patients, we assessed the extent to which ventricular-arterial coupling (VAC; Ea/Ees) affects LV twist, which may be a compensatory mechanism for systolic dysfunction.

Long-term outcomes of intravascular ultrasound-guided implantation of bare metal stents versus drug-eluting stents in primary percutaneous coronary intervention.

While drug-eluting stents (DESs) have shown favorable outcomes in ST-segment elevation myocardial infarction (STEMI) compared to bare metal stents (BMSs), there are concerns about the risk of stent thrombosis (ST) with DESs. Because intravascular ultrasound (IVUS) guidance may help optimize stent placement and improve outcomes in percutaneous coronary intervention (PCI) patients, we evaluated the impact of IVUS-guided BMS versus DES implantation on long-term outcomes in primary PCI.

Fever after primary percutaneous coronary intervention in ST-segment elevation myocardial infarction is associated with adverse outcomes.

Fever is a common finding after primary percutaneous coronary intervention (PPCI) in patients with ST-segment elevation myocardial infarction (STEMI). However, its prognostic value is not validated yet.

The efficacy of the cystatin C based glomerular filtration rate in the estimation of safe contrast media volume.

The risk of contrast-induced nephropathy (CIN) is significantly influenced by baseline renal function and the amount of contrast media (CM). We evaluated the usefulness of the cystatin C (CyC) based estimated glomerular filtration rate (eGFRCyC) in the prediction of CIN and to determine the safe CM dosage.

Association of cardio-ankle vascular index with diastolic heart function in hypertensive patients.

Arterial stiffness is an important risk factor of impaired left ventricular (LV) diastolic function as well as systolic dysfunction. The cardio-ankle vascular index (CAVI) and the ambulatory arterial stiffness index (AASI) can evaluate arteriosclerosis. We analyzed the relationship between arterial stiffness and diastolic function, and then compared the two methodologies to assess which method could serve as a more informative tool for diastology. In total, 136 patients with hypertension underwent 24-h ambulatory blood pressure monitoring (ABPM) and echocardiography including ventricular arterial coupling (VAC). Arterial stiffness was estimated using both CAVI and AASI derived from ABPM. Patients were classified into LV diastolic dysfunction and normal function groups. Those with diastolic dysfunction had a higher CAVI and AASI. Aside from LV torsion, mitral inflow parameters, tissue Doppler velocities and VAC showed a significantly greater association with CAVI, relative to AASI. The receiver operating characteristic curve analysis revealed that CAVI [area under the curve (AUC) = 0.869, p < 0.001] provided significantly more favorable accuracy for diastolic dysfunction compared with AASI (AUC = 0.672, p = 0.004). Multiple logistic regression analyses showed that CAVI [Odds ratio (OR) = 5.1, p = 0.009] had a greater association with diastolic dysfunction, relative to age, systolic blood pressure or AASI (OR = 1.4, p = 0.043). This study indicates that CAVI clinically provides diastolic functional information much better in hypertensive patients than AASI.

QRS prolongation in the prediction of clinical cardiac events in patients with acute heart failure: analysis of data from the Korean Acute Heart Failure Registry.

A prolonged QRS duration has been associated with an unfavorable prognosis in chronic compensated heart failure (HF). However, its predictive value during an admission for acute HF is limited, even in HF with a preserved ejection fraction (EF). The purpose of this study was to evaluate the prognostic utility of the QRS duration in acute HF.

Impact of home-based exercise training with wireless monitoring on patients with acute coronary syndrome undergoing percutaneous coronary intervention.

Recent studies have suggested a favorable effect of cardiac rehabilitation (CR) on patients with cardiovascular disease. This study aimed to evaluate the impact of home-based exercise training with wireless monitoring on acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI). A total of 55 ACS patients undergoing PCI were randomly divided into home based exercise training with wireless monitoring cardiac rehabilitation (CR, n = 26) and usual care (UC, n = 29). Exercise capacity and quality of life (QOL) were evaluated at baseline and after 12 weeks. Change of metabolic equivalent of the tasks, maximal exercise time and QOL were significantly increased (+2.47 vs +1.43, P = 0.021; +169.68 vs +88.31 sec, P = 0.012; and +4.81 vs +0.89, P = 0.022, respectively), and the change of submaximal rate pressure product, and of submaximal rate of perceived exertion were significantly decreased (-28.24 vs -16.21, P = 0.013; and -1.92 vs -1.62, P = 0.018, respectively) in the CR group compared to the UC group after 12 weeks. CR using home-based exercise training with wireless monitoring led to improvement of exercise capacity and QOL relative to conventional care in ACS patients undergoing PCI. Our findings suggest that early scheduled CR may be considered in ACS patients undergoing PCI.