Yoshio Kobayashi

Left ventricular (LV) extracellular volume fraction (ECV) quantified by cardiac computed tomography (CT) reflects diffuse myocardial fibrosis. In patients with atrial fibrillation (AF) and reduced LV ejection fraction (LVEF), distinguishing tachycardia-induced cardiomyopathy from underlying myocardial disease remains challenging. The prognostic value of ECV for predicting reverse remodeling (RR) after catheter ablation for AF remains uncertain. We retrospectively analyzed 102 patients with LVEF ≤ 50% on echocardiography who underwent cardiac CT before AF ablation between May 2015 and April 2025. RR was defined as a ≥15% reduction in LV end-systolic volume with recovery of LVEF > 50%, or an absolute increase in LVEF of ≥15%. RR occurred in 49 patients (48%). ECV was significantly lower in patients with RR than in those without (31.2 ± 3.5% vs. 37.6 ± 7.8%, p < 0.001). Receiver operating characteristic analysis identified an optimal cutoff of 34.8% (area under the curve 0.77; sensitivity 88%; specificity 62%, p < 0.001). In multivariable logistic regression analysis, lower ECV remained independently associated with RR (odds ratio 0.84; 95% confidence interval 0.75–0.95; p = 0.006). CT-derived ECV was associated with RR after AF ablation in patients with reduced LVEF and may provide additional information for clinical decision-making.

Background/Objectives: Effective regurgitant orifice area (EROA) is a critical parameter in assessing mitral regurgitation (MR) severity. The Japanese Circulation Society recommends a volumetric method which uses mitral annular diameters from apical four-chamber (A4C) and two-chamber (A2C) views. However, given the elliptical shape of the mitral annulus, use of apical long-axis (A3C) and A2C views, which reflect the anatomical long and short axes, may improve measurement accuracy. This study aimed to determine the optimal echocardiographic view combination for precise EROA quantification in degenerative MR (DMR). Methods: We retrospectively analyzed 98 patients with DMR who underwent both transthoracic echocardiography (TTE) and three-dimensional transesophageal echocardiography (3D TEE) within three months between April 2018 and December 2023. EROA was calculated using volumetric methods based on two TTE view combinations, A4C-A2C (EROA 4/2) and A3C-A2C (EROA 3/2). These were compared with 3D TEE-derived vena contracta area (VCA), which served as reference standard. Results: Mean values of EROA were 0.57 ± 0.23 cm² for EROA 4/2, 0.50 ± 0.21 cm² for EROA 3/2, and 0.49 ± 0.18 cm² for 3D TEE VCA. EROA 4/2 was significantly larger than VCA (p < 0.01), whereas EROA 3/2 did not significantly differ from VCA (p = 0.41) and showed a stronger correlation with VCA than EROA 4/2 (r = 0.829 vs. r = 0.638, p < 0.01). Conclusions: Volumetric EROA assessment using A3C and A2C views provides more accurate quantification in DMR than the conventional A4C and A2C approach. Anatomically appropriate imaging planes should be prioritized to enhance the accuracy of MR severity evaluation.

Cardiac computed tomography (CT) has long evolved as a highly accurate screening tool for coronary artery disease. New technologies such as multi-detector rows and artifact reduction by a new motion correction algorithm have made it possible to evaluate coronary artery stenosis with higher diagnostic accuracy and lower radiation exposure. In addition to the anatomical evaluation of coronary arteries, the introduction of fluid dynamic analysis enables the measurement of coronary fractional flow reserve (FFR) for each stenotic lesion, which can only be achieved through invasive catheter evaluation. Myocardial ischemia can now also be detected using myocardial stress perfusion CT imaging. In addition, with the advent of dual-energy imaging or new image reconstruction technology, the addition of late contrast phase imaging enables myocardial late enhancement and left ventricular (LV) extracellular volume (ECV) analysis, which was previously possible only with cardiac magnetic resonance imaging (MRI). It has also been reported that LV ECV may be useful in predicting prognosis in cases with cardiomyopathies. In addition, retrospective imaging of the entire heart in a single cardiac cycle is now possible with lower radiation exposure, enabling not only morphological evaluation of the heart and valves but also myocardial strain analysis, which has conventionally been evaluated mainly by echocardiography and is expected to be applied in clinical practice in the future. Cardiac CT, which overcomes the weaknesses of other modalities while demonstrating greater usefulness through the latest technological development, is expected to expand its field of application to the entire heart analysis. The purpose of this review is to provide an overview of the technological development of cardiac CT, which has seen remarkable development in recent years, along with its clinical utility, with the aim of enabling clinicians to fully utilize it in daily practice.

Background: Given that insulin resistance and lower levels of high-density lipoprotein cholesterol are reportedly associated with the development of coronary vasospasm, metabolic disorders may play a significant role in the underlying mechanisms of vasospastic angina (VSA). In this context, however, the impact of serum uric acid (SUA) levels on the diagnosis of VSA remains unclear. Methods: From May 2012 to March 2025, a total of 947 patients undergoing intracoronary acetylcholine (ACh) provocation tests for diagnosing VSA were included. Positive diagnosis of ACh provocation testing was defined as angiographic coronary spasm accompanied by chest symptoms and/or ischemic electrocardiographic changes. The primary interest of this study was to evaluate the potential relationship between SUA levels and ACh provocation test results. Results: Of the 947 patients, 497 (52.5%) had positive ACh provocation testing (i.e., VSA). Patients with positive ACh tests had significantly higher SUA levels than their counterparts (5.4 ± 1.6 vs. 5.2 ± 1.5 mg/dL, p = 0.039). The receiver operating characteristics curve analysis showed that SUA levels were predictive of positive ACh test results (area under the curve 0.538, best cut-off value 5.4 mg/dL, p = 0.040). In the multivariable logistic regression analysis, male sex and current smoking were identified as predictors of positive ACh testing, while SUA levels were not. Conclusions: Patients diagnosed with VSA had a higher SUA level than patients without VSA. However, this association was confounded with other factors, such as male sex and current smoking.

Extracellular volume fraction (ECV) analysis on computed tomography (CT) is now available. The purpose of this study was to assess the usefulness of CT-derived ECV analysis for predicting outcomes in patients with hypertrophic cardiomyopathy (HCM). One hundred and one HCM patients (67 males, 66 ± 11 years old) who received cardiac CT between January 2009 and December 2021 were included. We measured left ventricular (LV) ECV (LV-ECV) on CT and investigated the relationship between LV-ECV and the major adverse cardiac events (MACE) after CT. Fifteen patients (15%) experienced MACE. The patients with MACE had a significantly higher LV-ECV, left atrial diameter, LV end-systolic diameter, and lower LVEF than those without MACE. The proportion of dilated phase HCM was significantly higher in the patients with MACE than those without MACE. LV-ECV and LVEF were significant predictors of MACE based on the multivariate analysis by Cox proportional hazards model. The optimal threshold of LV-ECV to predict MACE was 37.6% based on the receiver operating characteristic analysis. The patients with LV-ECV ≥ 37.6% (30 patients) experienced significantly higher MACE than those with LV-ECV < 37.6% (p < 0.001). CT-derived ECV analysis suggested potential usefulness for predicting MACE in patients with HCM.

Introduction: Prosthesis-patient mismatch (PPM) in surgical aortic valve replacement (SAVR) is known to be a poor prognostic factor. However, the parameters for preventing postoperative PPM in SAVR have not been established. Materials and Methods: Two hundred and five patients (mean age 72.5 ± 7.4 years, 129 males) who underwent SAVR were analyzed. Preoperatively, we determined the recommended prosthesis valve size from the mean aortic valve (AV) diameter derived from the AV annulus area by preoperative three-dimensional transesophageal echocardiography (3D-TEE). We investigated the association between pre- and postoperative changes in annulus diameter and the occurrence of PPM. Results: PPM was present in 6 patients (2.9%). Pre- and postoperative AV annulus diameter change ratio was greater in the group with PPM than in that without PPM (10.4 ± 3.6% vs. 3.0 ± 5.6%, p = 0.002). The use of prosthetic valve rings smaller than the recommended size was higher in the group with PPM than in that without PPM. (83.3% vs. 20.6%, p = 0.002). On multivariate logistic regression analysis, use of a valve smaller than the recommended size was an independent predictor of PPM (odds ratio 19.3, 95% confidence interval 2.14–174.5, p = 0.008). Conclusions: The recommended prosthetic AV size based on preoperative 3D-TEE is useful for determining the optimal prosthetic AV size to prevent PPM after SAVR.

Aortic valve stenosis (AS) is a valvular heart disease that imposes a high afterload on the left ventricle (LV) due to restricted opening of the aortic valve, resulting in LV hypertrophy. Severe AS can lead to syncope, angina pectoris, and heart failure. The number of patients with AS has been increasing due to aging populations, the growing prevalence of lifestyle-related diseases, and advances in diagnostic technologies. Therefore, accurate diagnosis and appropriate treatment of AS are essential. In recent years, transcatheter aortic valve implantation (TAVI) has become feasible, and the number of procedures has rapidly increased, particularly among elderly patients. As treatment options for AS expand and diversify, detailed pre-procedural evaluation has become increasingly important. In particular, diagnostic imaging modalities such as computed tomography (CT) have advanced significantly, with notable improvements in image quality. With recent advancements in CT technology—such as increased detector rows, faster gantry rotation speeds, new image reconstruction methods, and the introduction of dual-energy imaging—the scope of cardiac assessment has expanded beyond the coronary arteries to include valves, myocardium, and the entire heart. This includes evaluating restricted AV opening and cardiac function using four-dimensional imaging, assessing AV annulus diameter and AS severity via calcium scoring with a novel motion correction algorithm, and detecting myocardial damage through late-phase contrast imaging using new reconstruction techniques. In cases of pre-TAVI evaluation or congenital bicuspid valves, CT is also valuable for assessing extracardiac structures, such as access routes and associated congenital heart anomalies. In addition, recent advancements in CT technology have made it possible to significantly reduce radiation exposure during cardiac imaging. CT has become an extremely useful tool for comprehensive cardiac evaluation in patients with aortic stenosis, especially those being considered for surgical treatment.

Introduction: Extracellular volume (ECV) analysis using computed tomography is recognized as a potential method for diagnostic application. It is currently the only noninvasive method for quantitatively evaluating myocardial fibrosis in dialysis patients for whom gadolinium contrast agents are contraindicated. In this study, we assessed the utility of ECV measurement via CT in the left ventricular (LV) myocardium (LVM) to predict major adverse cardiac events (MACEs) in dialysis patients. Materials and methods: We analyzed 57 dialysis patients who underwent cardiac CT and assessed the utility of LVM ECV (LV-ECV) for predicting MACEs. All the patients were followed for a median of 11 months, and MACEs occurred in 15 cases (26%). Results: LV-ECV and plasma brain natriuretic peptide levels were higher in subjects with MACEs than those without (40.29 ± 8.23% vs. 33.76 ± 4.60% and 1481 ± 997 vs. 807 ± 1109 pg/mL; both p < 0.05). Significant valvular disease was more frequently detected in patients with MACEs than those without (60% vs. 24%; p = 0.023). Serum hematocrit levels were significantly lower in patients with MACEs than those without (29 ± 5 vs. 34 ± 5; p < 0.001). The administration of statin was significantly lower in patients with MACEs than in those without (13% vs. 48%; p = 0.029). A receiver operating characteristic (ROC) curve analysis was performed using LV-ECV for predicting MACEs. The area under the curve was 0.80, and the best cut-off value of LV-ECV was 37.26% (p = 0.0003). In a Cox proportional hazards model, LV-ECV ≥ 37.26% was the only significant independent predictor of MACEs (p = 0.020). Conclusions: LV-ECV measured using CT is a useful predictor of MACEs in dialysis patients.

Objective: Cardiac computed tomography (CT) helps screen coronary artery stenosis in cases with dilated cardiomyopathy (DCM). Extracellular volume fraction (ECV) analysis has recently been eligible for CT. Method: We evaluated the impact of ECV on the CT to predict the prognosis in DCM patients with heart failure with reduced ejection fraction (HFrEF). Patients or Materials: We analyzed 101 consecutive DCM cases with HFrEF who underwent cardiac CT. All the patients had a lower left ventricular (LV) ejection fraction (LVEF) of less than 40%. We evaluated the effect of ECV to predict the patients’ prognosis. Cardiovascular death, hospitalization due to heart failure, and fatal arrhythmic events were included in the major adverse cardiac events (MACE). Results: MACE occurred in 27 cases (27%). The patients with MACE (27 cases) had an increased ECV on the LVM on the CT (37.2 ± 6.7 vs. 32.2 ± 3.6%, p = 0.0008) compared to the others (74 cases). Based on the receiver operating characteristics curve analysis, the best cutoff value of the ECV on the LVM to predict the MACE was 32.3%. The patients with ECV ≥ 32.3% had significantly higher MACE based on the Kaplan–Meier analysis. The ECV on the LVM was a significant marker to predict MACE based on the univariate Cox proportional hazard model (hazard ratio of 8.00, 95% confidence interval 1.88–33.97, p = 0.0048). Conclusions: ECV by CT is helpful to predict MACE in cases with DCM and HFrEF.