• Clinical and Experimental Pediatrics
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• 제56권3호
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• pp.101-106
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• 2013

Despite developments in surgical techniques and other interventions, right ventricular (RV) failure remains an important clinical problem in several congenital heart diseases (CHD). RV function is one of the most important predictors of mortality and morbidity in patients with CHD. RV failure is a progressive disorder that begins with myocardial injury or stress, neurohormonal activation, cytokine activation, altered gene expression, and ventricular remodeling. Pressure-overload RV failure caused by RV outflow tract obstruction after total correction of tetralogy of Fallot, pulmonary stenosis, atrial switch operation for transposition of the great arteries, congenitally corrected transposition of the great arteries, and systemic RV failure after the Fontan operation. Volume-overload RV failure may be caused by atrial septal defect, pulmonary regurgitation, or tricuspid regurgitation. Although the measurement of RV function is difficult because of many reasons, the right ventricle can be evaluated using both imaging and functional modalities. In clinical practice, echocardiography is the primary mode for the evaluation of RV structure and function. Cardiac magnetic resonance imaging is increasingly used for evaluating RV structure and function. A comprehensive evaluation of RV function may lead to early and optimal management of RV failure in patients with CHD.

• Journal of Cardiovascular Imaging
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• 제26권4호
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• pp.189-200
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• 2018

Pulmonary hypertension (PH) is defined as resting mean pulmonary artery pressure ${\geq}25mmHg$ and is caused by multiple etiologies including heart, lung or other systemic diseases. Evaluation of right ventricular (RV) function in PH is very important to plan treatment and determine prognosis. However, quantification of volume and function of the RV remains difficult due to complicated RV geometry. A number of imaging tools has been utilized to diagnose PH and assess RV function. Each imaging technique including conventional echocardiography, three-dimensional echocardiography, strain echocardiography, computed tomography and cardiac magnetic resonance imaging has-advantages and limitations and can provide unique information. In this article, we provide a comprehensive review of the utility, advantages and shortcomings of the multimodality imaging used to evaluate patients with PH.

• 전기학회논문지
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• 제58권6호
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• pp.1065-1070
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• 2009

This paper presents the new technique of modeling using Dynamic Link Library(DLL) in ElectroMagnetic Transients Program - Restructured Version(EMTP-RV) in which we have simplified the procedures of OverCurrent Relay(OCR) modeling. The DLL function is designed to allow EMTP-RV users to develop advanced program model modules and interface them directly and intimately with the EMTP-RV engine. The modeled OCR is verified by simulating the various fault cases in the distribution system. Also, the performance for the modeling of OCR using DLL is compared with that of the method using the control components of EMTP-RV and using EMTP/MODELS. The results show the validity of modeled OCR and the effectiveness of the method using DLL function.

• Clinical and Experimental Pediatrics
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• 제56권6호
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• pp.235-241
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• 2013

Repair of tetralogy of Fallot (TOF) has shown excellent outcomes. However it leaves varying degrees of residual hemodynamic impairment, with severe pulmonary stenosis (PS) and free pulmonary regurgitation (PR) at both ends of the spectrum. Since the 1980s, studies evaluating late outcomes after TOF repair revealed the adverse impacts of residual chronic PR on RV volume and function; thus, a turnaround of operational strategies has occurred from aggressive RV outflow tract (RVOT) reconstruction for complete relief of RVOT obstruction to conservative RVOT reconstruction for limiting PR. This transformation has raised the question of how much residual PS after conservative RVOT reconstruction is acceptable. Besides, as pulmonary valve replacement (PVR) increases in patients with RV deterioration from residual PR, there is concern regarding when it should be performed. Regarding residual PS, several studies revealed that PS in addition to PR was associated with less PR and a small RV volume. This suggests that PS combined with PR makes RV diastolic property to protect against dilatation through RV hypertrophy and supports conservative RVOT enlargement despite residual PS. Also, several studies have revealed the pre-PVR threshold of RV parameters for the normalization of RV volume and function after PVR, and based on these results, the indications for PVR have been revised. Although there is no established strategy, better understanding of RV mechanics, development of new surgical and interventional techniques, and evidence for the effect of PVR on RV reverse remodeling and its late outcome will aid us to optimize the management of TOF.

• Korean Journal of Radiology
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• 제21권4호
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• pp.450-461
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• 2020

Objective: We performed a meta-analysis to evaluate the agreement of cardiac computed tomography (CT) with cardiac magnetic resonance imaging (CMRI) in the assessment of right ventricle (RV) volume and functional parameters. Materials and Methods: PubMed, EMBASE, and Cochrane library were systematically searched for studies that compared CT with CMRI as the reference standard for measurement of the following RV parameters: end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), or ejection fraction (EF). Meta-analytic methods were utilized to determine the pooled weighted bias, limits of agreement (LOA), and correlation coefficient (r) between CT and CMRI. Heterogeneity was also assessed. Subgroup analyses were performed based on the probable factors affecting measurement of RV volume: CT contrast protocol, number of CT slices, CT reconstruction interval, CT volumetry, and segmentation methods. Results: A total of 766 patients from 20 studies were included. Pooled bias and LOA were 3.1 mL (-5.7 to 11.8 mL), 3.6 mL (-4.0 to 11.2 mL), -0.4 mL (5.7 to 5.0 mL), and -1.8% (-5.7 to 2.2%) for EDV, ESV, SV, and EF, respectively. Pooled correlation coefficients were very strong for the RV parameters (r = 0.87-0.93). Heterogeneity was observed in the studies (I² > 50%, p < 0.1). In the subgroup analysis, an RV-dedicated contrast protocol, ≥ 64 CT slices, CT volumetry with the Simpson's method, and inclusion of the papillary muscle and trabeculation had a lower pooled bias and narrower LOA. Conclusion: Cardiac CT accurately measures RV volume and function, with an acceptable range of bias and LOA and strong correlation with CMRI findings. The RV-dedicated CT contrast protocol, ≥ 64 CT slices, and use of the same CT volumetry method as CMRI can improve agreement with CMRI.

• Clinical and Experimental Pediatrics
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• 제50권11호
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• pp.1055-1060
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• 2007

Right-sided heart failure is a major problem among patients with congenital heart diseases, due to the prevalence of congenital heart defects and the association of pulmonary hypertension. More attention is focused on the structure of the right heart particularly in association with congenital heart defects and chronic lung disease. The right ventricle (RV) may support the pulmonary circulation, and sometimes the systemic circulation (systemic RV) in congenital heart defects. Despite major progress being made, assessing the RV remains challenging, often requiring a multi-imaging approach and expertise (echocardiography, magnetic resonance imaging, nuclear and cineangiography). Evidence is accumulating that RV dysfunction develops in many of these patients and leads to considerable morbidity and mortality. While there is extensive literature on the pathophysiology and treatment of left heart failure, the data for right-sided heart failure is scarce. Therefore RV function in certain groups of congenital heart disease patients needs close surveillance and timely and appropriate intervention to optimise outcomes. An understanding of RV physiology and hemodynamics will lead to a better understanding of current and future treatment strategies for right heart failure. This will review right-sided heart failure with the implications of volume and pressure loading of the RV in congenital heart diseases.

• Journal of Microbiology and Biotechnology
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• 제26권6호
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• pp.1046-1056
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• 2016

RV-23 is a melittin-related antibacterial peptide (MRP) with lower cytotoxicity than either melittin or AR-23, another MRP. The aim of this study was to explore the mechanism of RV-23's antibacterial selectivity and its hemocompatibility. The results showed that all the peptides exhibited lytic activity against Staphylococcus aureus and Escherichia coli, with RV-23 showing the highest potency. Moreover, RV-23 had lower cytotoxicity than melittin or AR-23 at their minimal inhibitory concentration. In addition, CD experiments showed that melittin, RV-23, and AR-23 all had a typical α-helical structure, and RV-23 had the lowest α-helix content. The structural information showed that RV-23 has the lowest hydrophobicity and highest hydrophobic moment. Because hydrophobicity and α-helix content are believed to correlate with hemolysis, the results indicate that the selective lytic activity against bacteria of RV-23 may be due to its low hydrophobicity and α-helicity, which lead to low cytotoxicity without affecting antibacterial activity. Furthermore, RV-23 did not affect the structure and function of blood components such as red blood cells, platelets, albumin, and the blood coagulation system. In conclusion, RV-23 is a cell-selective antibacterial peptide with high hemocompatibility due to its unique structure.

• Clinical and Experimental Pediatrics
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• 제57권11호
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• pp.484-488
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• 2014

Purpose: Chronic upper airway obstruction causes hypoxemic pulmonary vasoconstriction, which may lead to right ventricle (RV) dysfunction. Adenotonsillar hypertrophy (ATH) is the most common cause of upper airway obstruction in children. Therefore, we aimed to evaluate RV function in children with ATH. Methods: Twenty-one children (male/female, 15/6; mean age, $92.3{\pm}39.0$ months; age range, 4-15 years) with ATH and 21 healthy age- and gender-matched controls were included in this study. Tricuspid annular plane systolic excursion and RV myocardial performance index were measured by transthoracic echocardiography. Further, the plasma level of N-terminal of probrain natriuretic peptide (NT-proBNP), an indicator of RV function, was determined. Results: The snoring-tiredness during daytime-observed apnea-high blood pressure (STOP) questionnaire was completed by the patients' parents, and loud snoring was noted in the ATH group. The plasma NT-proBNP level was significantly higher in the ATH group than that in the controls ($66.44{\pm}37.63pg/mL$ vs. $27.85{\pm}8.89pg/mL$, P=0.001). The echocardiographic parameters were not significantly different between the groups. Conclusion: We were unable to confirm the significance of echocardiographic evidence of RV dysfunction in the management of children with ATH. However, the plasma NT-proBNP level was significantly higher in the ATH group than that in the control, suggesting that chronic airway obstruction in children may carry a risk for cardiac dysfunction. Therefore, more patients should be examined using transthoracic echocardiography. In addition, pediatricians and otolaryngologists should consider cardiologic aspects during the management of children with severe ATH.

• Journal of Yeungnam Medical Science
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• 제34권2호
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• pp.238-241
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• 2017

Background: We investigated the difference in right ventricle (RV) volume and ejection fraction (EF) according to the pulmonary valve (PV) annular extension technique during Tetralogy of Fallot (TOF) total correction. Methods: We divided patients who underwent the procedure from 1993 to 2003 into two groups according to PV extension technique (group I: PV annular extension, group II: no PV annular extension) during TOF total correction. We then analyzed the three segmental (RV inlet, trabecular and outlet) and whole RV volume and EF by cardiac magnetic resonance imaging (MRI). Results: Fourteen patients were included in this study (group I: 10 patients, group II: four patients; male: nine patients, female: five patients). Cardiac MRI was conducted after a 16.1 years TOF total correction follow-up period. There was no statistical difference in RV segmental volume index or EF between groups (all p>0.05). Moreover, the total RV volume index and EF did not differ significantly between groups (all p>0.05). Conclusion: The RV volume and EF of the PV annular extension group did not differ from that of the PV annular extension group. Thus, PV annular preservation technique did not show the surgical advantage compared to PV annular extension technique in this study.

• Korean Journal of Radiology
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• 제22권12호
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• pp.1946-1963
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• 2021

Cardiac computed tomography (CT) and cardiac magnetic resonance imaging (CMR) can reveal the detailed anatomy and function of the tricuspid valve and right ventricle (RV). Quantification of tricuspid regurgitation (TR) and analysis of RV function have prognostic implications. With the recently available transcatheter treatment options for diseases of the tricuspid valve, evaluation of the tricuspid valve using CT and CMR has become important in terms of patient selection and procedural guidance. Moreover, CT enables post-procedural investigation of the causes of valve dysfunction, such as pannus or thrombus. This review describes the anatomy of the tricuspid valve and CT and CMR imaging protocols for right heart evaluation, including RV function and TR analyses. We also demonstrate the pre-procedural planning for transcatheter treatment of TR and imaging of postoperative complications using CT.