• The Journal of the Korea Contents Association
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• v.21 no.2
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• pp.437-444
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• 2021

The aim of this study was to compare the cardiac CT and cardiac MRI in calculating and correcting the left ventricle ejection fraction by analyzing the physical and temporal resolution for reducing the misdiagnosis rate. One hundred thirty-eight patients with aortic value regurgitation who underwent both cardiac CT and cardiac MRI were analyzed. Left ventricle ejection fractions calculated from each exam were corrected based on the physical and temporal resolution differences and the reliability test evaluated whether the misdiagnosis rate of cardiac CT was improved after the correction. As a result of the study, the misdiagnosis rate of cardiac CT ejection fraction before correcting the difference in physical and temporal resolution was 38.4%(53 persons). In addition, it can be seen that the corrected cardiac CT ejection fraction confirmed in the Bland-Altman plot was highly consistent with the ejection fraction of cardiac MRI. In conclusion, as the cardiac CT is less well suited for measuring ejection fraction, physical characteristics and the time resolution correction using cardiac MRI is needed and the misdiagnosis rate after correction decreased to 14.5%(20 persons). Therefore, this study appears more appropriate for better prediction of ejection fraction and clinical utility.

• Journal of Magnetics
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• v.17 no.3
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• pp.229-232
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• 2012

This study examined the correlation between MR cine and myocardium Single-photon emission computed tomography (SPECT) by comparing the measured cardiac ejection fractions. The usefulness of cardiac MRI was also evaluated. Ten patients (8 men, 2 women and average age of 58.6 years), who underwent a myocardium SPECT scan and cardiac cine MRI scan among patients who visited the hospital for the chief complaint of cardiac disorder from June 1, 2010 to February 10, 2011, were enrolled in this study. The cardiac ejection fraction was calculated from the images obtained in both scans. The data was used to examine the correlation. The regression equation the cardiac ejection fraction values of the 10 patients obtained in myocardium SPECT and MRI cine was Y = 1.12X-8.91 ($R^2$ = 0.78, significance of F = 0.001639, and confidence level of 95%). The results were significant when the cardiac ejection fraction obtained from MRI cine was compared with that obtained from myocardium SPECT. Overall, a cardiac examination using MRI enables an investigation of not only the ejection fraction but also the ED and ES volumes, stroke volume, wall thickness, and wall thickening in a higher spatial resolution despite the examination being conducted once. This examination is believed to be very useful for diagnosing patients with cardiac disease.

• Journal of the Korean Society of Radiology
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• v.5 no.5
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• pp.289-294
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• 2011

The aim of this study is to evaluate the differences of ejection fraction of left ventricle through the quantitative analysis of diastolic and systolic volumes according to slices selected using cardiac MR imaging. A total of 12 volunteers (7 normal, 1 myocardium bridge, and 4 arrhythmia) underwent cardiac MRI on a MR scanner(Magnetom Trio, Siemens, Germany). Ejection fractions for quantitative analysis were calculated at single slice of center of left ventricle, 3, 5, and 6-7 slices extending from the center of left ventricle. Average values were analyzed for evaluating differences of ejection fraction according to the number of slices selected. Mean value of normal person of ejection fraction were 67.14% at single slice of center of left ventricle, 66.24% at 3 slices, 65.63% at 5 slices, and 65.29% at 6-7 slices. While ejection fraction obtained from a patient with 61.74% at single slice of center of left ventricle, 60.92% at 3 slices, 60.89% at 5 slices, and 61.89% at 6-7 slices. There was no significant differences by the number of slices selected. This study demonstrates that ejection fraction obtained from single slice of center of left ventricle may represent a optimum parameter for cardiac function, instead of the value calculated on the variable slices selected.

• The Korean Journal of Nuclear Medicine
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• v.25 no.2
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• pp.186-191
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• 1991

Radionuclide cardiac studies lend themselves exceptionally well to functional imaging. This is especially true for gated blood pool scan (GBP). Making functional images is also possible in radionuclide angiocardiography (RNAC). In this study we tried to validate the functional images obtained from RNAC by comparing it with GBP. Twenty three patients (16 patients with coronary artery diseases, 5 with hypertensive heart diseases, and 2 with nonspecific chest pains) underwent simultaneous RNAC and GBP at the same position (LAO $45^{\circ}$). From both studies, global ejection fraction, regional ejection fraction, phase image, amplitude image, stroke image, paradox image, maximum ejection and maximum filling rates were obtained. Global ejection fraction are almost same in both studies. Regional ejection fractions of apex and inferior portion of left ventricle calculated from RNAC are well correlated with those of GBP. Phase and paradox image, maximum ejection and maximum filling rates were obtained. Global ejection fraction are almost same in both studies. Regional ejection fractions of apex and inferior portion of left ventricle calculated from RNAC are well correlated with those of GBP. Phase and paradox images of RNAC are very similar to those of GBP. However, amplitude and stroke images are different. Regional ejection fractions of the left ventricular base, maximum ejection and maximum filling rates obtained from RNAC are significantly different from those of GBP. In conclusion, albeit all of functional images of RNAC is not same as GBP, regional walt motions and global left ventricular function are expected to be successfully analyzed by phase and paradox image and ejection fraction.

• Korean Circulation Journal
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• v.52 no.4
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• pp.251-264
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• 2022

Heart failure with preserved ejection fraction (HFpEF) accounts for approximately half of all heart failure (HF) cases. The prevalence of HFpEF is increasing due to an aging population with hypertension, diabetes mellitus, and obesity. HFpEF remains a challenging clinical entity due to a lack of effective treatment options. Traditional HF medications have not been shown to reduce mortality of patients with HFpEF, and an implantable cardioverter-defibrillator is not indicated due to normal ejection fraction. Sudden death is the most common mode of death in patients with HFpEF; however, the underlying mechanisms of sudden death are not fully elucidated. Although ventricular arrhythmias are responsible for the majority of sudden deaths in general, their contribution to sudden deaths in HFpEF patients is likely less significant. The mechanisms of ventricular arrhythmias in HFpEF are 1) reduced conduction velocity due to ventricular hypertrophy, 2) delayed repolarization due to potassium current down-regulation, 3) calcium leakage due to altered excitation-contraction coupling, and 4) increased ventricular fibrosis caused by systemic inflammation. Hypertension and subsequent ventricular hypertrophy reduce the conduction velocity in HFpEF hearts via heterogeneous distribution of connexin 43. Delayed repolarization caused by potassium current down-regulation in HFpEF hearts provides a window for early afterdepolarization to trigger ventricular arrhythmias. Altered excitation-contraction coupling in HFpEF can cause calcium to leak and trigger delayed afterdepolarization. Increased systemic inflammation and subsequent ventricular fibrosis provide substrates for re-entry. Further research is warranted to investigate the detailed mechanisms of ventricular arrhythmias in HFpEF.

• The Korean Journal of Nuclear Medicine
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• v.27 no.1
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• pp.135-139
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• 1993

Radionuclide cardioangiography has been widely applied and has played major roles in non-invasive assessment of cardiac function. Three techniques, first-pass, gated first and gated equilibrium methods, have commonly been used to evaluate right ventricular ejection fraction which usually abnormal in the patients with cardiopulmonary disease. It has been known that the gated first pass method is the most accurate method among the three techniques in assessment of right ventricular ejection fraction. The radionuclide right ventricular ejection fraction values were determined in 13 normal subjects and in 15 patients with chronic obstructive pulmonary disease by the gated first pass method and compared with those of the first pass method because there ha,j been no published data of right ventricular ejection fraction by the gated first pass method in Korea. The values of right ventricular ejection fraction by the gated first pass method were compared with the detas from the pulmonary function test performed in the patients with chronic obstructive pulmomary disease. The results were as follows: 1) The values of right ventricular ejection fraction by the gated first pass method were $50.1{\pm}6.1%$ in normal subjects and $38.5{\pm}8.5$ in the patients with chronic obstructive pulmonary disease. There was statistically significant difference between the right ventricular ejection fraction of each of the two groups (p < 0.05). 2) The right ventricular ejection fraction by the gated first pass method was not linearly correlated with $FEV_1$, VC, DLCO, and FVC as well as $P_aO_2$ and $P_aCO_2$ of the patients with chronic obstructive pulmonary disease. We concluded that right ventricular ejection fraction by the gated first pass method using radionuclide cardioangiography may be useful in clinical assessment of the right ventricular function.

• The Korean Journal of Nuclear Medicine
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• v.16 no.1
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• pp.1-6
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• 1982

To evaluate the usefulness of radionuclide cardiac angiography in the assessment of right ventricular function, we measured right ventricular ejection fraction (RVEF) using single pass method. In 12 normal persons, RVEF averaged $52.7{\pm}5.9%(mean{\pm}S.D.)$. In 25 patients with chronic obstructive lung disease, RVEF was $37.2{\pm}10.6%$ and significantly lower than that of normal persons (p<0.01). All 10 patients with right ventricular failure had abnormal RVEF, which was significantly lower than that of 14 patients without right ventricular failure ($27.6{\pm}5.7%,\;43.9{\pm}8.5%$, respectively. p<0.01). It concluded thal RVEF measured by single pass radionuclide cardiac angiography was a useful, noninvasive method to assess right ventricular function.

• Korean Circulation Journal
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• v.53 no.9
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• pp.621-631
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• 2023

Background and Objectives: The morphology-voltage-P-wave duration (MVP) electrocardiography (ECG) risk score is a newly defined scoring system that has recently been used for atrial fibrillation (AF) prediction. The aim of this study was to evaluate the ability of the MVP ECG risk score to predict AF in patients with an implantable cardioverter defibrillator (ICD) and heart failure with reduced ejection fraction in long-term follow-up. Methods: The study used a single-center, and retrospective design. The study included 328 patients who underwent ICD implantation in our hospital between January 2010 and April 2021, diagnosed with heart failure. The patients were divided into low, intermediate and high-risk categories according to the MVP ECG risk scores. The long-term development of atrial fibrillation was compared among these 3 groups. Results: The low-risk group included 191 patients, the intermediate-risk group 114 patients, and the high-risk group 23 patients. The long-term AF development rate was 12.0% in the low-risk group, 21.9% in the intermediate risk group, and 78.3% in the high-risk group. Patients in the high-risk group were found to have 5.2 times higher rates of long-term AF occurrence compared to low-risk group. Conclusions: The MVP ECG risk score, which is an inexpensive, simple and easily accessible tool, was found to be a significant predictor of the development of AF in the long-term follow-up of patients with an ICD with heart failure with reduced ejection fraction. This risk score may be used to identify patients who require close follow-up for development and management of AF.

• The Journal of Korean Physical Therapy
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• v.31 no.5
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• pp.322-327
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• 2019

Purpose: This study examined the influence of the maximal aerobic capacity on the two-year cardiac-related re-hospitalization in patients with heart failure with a reduced ejection fraction (HFrEF) in Korean society. Methods: The maximal aerobic capacity of the study population (n=95, male 63%) was evaluated using a cardiopulmonary exercise (CPX) testing system. Each patient was followed up for two years to divide the HFrEF patients into two groups according to cardiac-related re-hospitalization: re-hospitalization (RH) group (n=29, 30%) and no re-hospitalization (NRH) group (n=66, 70%). Results: The relative peak $VO_2$ (mL/kg/min, p<0.001), exercise duration (p<0.001), respiratory exchange ratio ($VCO_2/VO_2$, p=0.001), systolic blood pressure (SBP) reserve (p=0.004), heart rate (HR) reserve (p=0.007), SBP max (p=0.02), and HR max (p=0.039) were significantly lower in the RH group than the NRH group during the CPX test. On the other hand, the ventilatory efficiency (VE/VCO2 slope, p=0.02) and age (p=0.022) were significantly higher in the RH group than in the NRH group. In binary logistic regression analysis, the relative peak $VO_2$ (p=0.001, Wald Chi-square 10.137) was the strongest predictive factor on cardiac-related re-hospitalization, which was followed by $VCO_2/VO_2$ (p=0.019, Wald Chi-square 5.54). On the other hand, age (p=0.063, Wald Chi-square 3.445) did not have a significant influence on cardiac related re-hospitalization. Conclusion: The maximal aerobic capacity, especially the relative peak $VO_2$, is the strongest factor on cardiac-related re-hospitalization within two years in patients with HFrEF in Korean society.

• The KIPS Transactions:PartB
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• v.18B no.2
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• pp.57-66
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• 2011

To prevent cardiac diseases, quantifying cardiac function is important in routine clinical practice by analyzing blood volume and ejection fraction. These works have been manually performed and hence it requires computational costs and varies depending on the operator. In this paper, an automatic left ventricle segmentation algorithm is presented to segment left ventricle on cardiac magnetic resonance images. After coil sensitivity of MRI images is compensated, a K-mean clustering scheme is applied to segment blood area. A graph searching scheme is employed to correct the segmentation error from coil distortions and noises. Using cardiac MRI images from 38 subjects, the presented algorithm is performed to calculate blood volume and ejection fraction and compared with those of manual contouring by experts and GE MASS software. Based on the results, the presented algorithm achieves the average accuracy of 6.2mL${\pm}$5.6, 2.9mL${\pm}$3.0 and 2.1%${\pm}$1.5 in diastolic phase, systolic phase and ejection fraction, respectively. Moreover, the presented algorithm minimizes user intervention rates which was critical to automatize algorithms in previous researches.