Extensive ablation for persistent atrial fibrillation patients with mitral regurgitation: Insights from the EARNEST-PVI prospective randomized trial.

BACKGROUND: Extensive ablation in addition to pulmonary vein isolation (PVI) in patients with persistent atrial fibrillation (AF) has not yielded consistent results, indicating diversity in their efficacy. Mitral regurgitation (MR) associated with AF may indicate a higher prevalence of arrhythmogenic substrate, suggesting potential benefits of extensive ablation for these patients. METHODS: This post-hoc analysis of the EARNEST-PVI trial compared PVI alone versus an extensive ablation strategy (PVI-plus) in persistent AF patients, stratified by MR presence. The primary endpoint of the study was the recurrence of AF. The secondary endpoints included death, cerebral infarction, and procedure-related complications. RESULTS: The trial included 495 eligible patients divided into MR and non-MR groups. The MR group consisted of 192 patients (89 in the PVI-alone arm and 103 in the PVI-plus arm), while the non-MR group had 303 patients (158 in the PVI-alone arm and 145 in the PVI-plus arm). In the non-MR group, recurrence rates were similar between PVI-alone and PVI-plus arms (Log-rank P = 0.47, Hazard ratio = 0.85 [95%CI: 0.54-1.33], P = 0.472). However, in the MR group, PVI-plus was significantly more effective in preventing AF recurrence (Log-rank P = 0.0014, Hazard ratio = 0.40 [95%CI: 0.22-0.72], P = 0.0021). No significant differences were observed in secondary endpoints between the two arms. CONCLUSIONS: For persistent AF patients with mild or greater MR, receiving PVI-plus was superior to PVI-alone in preventing AF recurrence. Conversely, for patients without MR, the effectiveness of extensive ablation was not demonstrated. These findings suggest tailoring ablation strategies based on MR presence can lead to better outcomes in AF management.

Recurrent Pericardial Effusion Resulting From Right Ventricular Free Wall Injury Caused by Leadless Pacemaker Tines.

An 87-year-old man developed delayed cardiac tamponade 55 min after leadless pacemaker implantation and recurrent pericardial effusion 20 days later. Electrocardiogram-gated enhanced cardiac computed tomography revealed that the leadless pacemaker tines on the lateral side had penetrated the right ventricular free wall. He underwent off-pump hemostatic surgery.

Sex Differences in Cardiovascular Disease-Related Hospitalization and Mortality in Japan　- Analysis of Health Records From a Nationwide Claim-Based Database, the Japanese Registry of All Cardiac and Vascular Disease (JROAD).

BACKGROUND: The prevalence of cardiovascular disease (CVD) is rising in Japan with its aging population, but there is a lack of epidemiological data on sex differences in CVD, including acute coronary syndrome (ACS), acute heart failure (AHF), and acute aortic disease.Methods and Results: This retrospective study analyzed data from 1,349,017 patients (January 2012-December 2020) using the Japanese Registry Of All Cardiac and Vascular Diseases database. ACS patients were youngest on average (70.5±12.9 years) and had the lowest female proportion (28.9%). AHF patients had the oldest mean age (79.7±12.0 years) and the highest proportion of females (48.0%). Acute aortic disease had the highest in-hospital mortality (26.1%), followed by AHF (11.5%) and ACS (8.9%). Sex-based mortality differences were notable in acute aortic disease, with higher male mortality in Stanford Type A acute aortic dissection (AAD) with surgery (males: 14.2% vs. females: 10.4%, P<0.001) and similar rates in Type B AAD (males: 6.2% vs. females: 7.9%, P=0.52). Aging was a universal risk factor for in-hospital mortality. Female sex was a risk factor for ACS and acute aortic disease but not for AHF or Types A and B AAD. CONCLUSIONS: Sex-based disparities in the CVD-related hospitalization and mortality within the Japanese national population have been highlighted for the first time, indicating the importance of sex-specific strategies in the management and understanding of these conditions.

Appropriate Selection of Substrate Ablation for Persistent Atrial Fibrillation Using Intraprocedural Assessment.

BACKGROUND: It has not been fully elucidated which patients with persistent atrial fibrillation (PerAF) should undergo substrate ablation plus pulmonary vein isolation (PVI). This study aimed to identify PerAF patients who required substrate ablation using intraprocedural assessment of the baseline rhythm and the origin of atrial fibrillation (AF) triggers.Methods and Results: This was a post hoc subanalysis using extended data of the EARNEST-PVI trial, a prospective multicenter randomized trial comparing PVI-alone and PVI-plus (i.e., PVI with added catheter ablation) arms. We divided 492 patients into 4 groups according to baseline rhythm and the location of AF triggers before PVI: Group A (n=22), sinus rhythm with pulmonary vein (PV)-specific AF triggers (defined as reproducible AF initiation from PVs only); Group B (n=211), AF with PV-specific AF triggers; Group C (n=94), sinus rhythm with no PV-specific AF trigger; Group D (n=165), AF with no PV-specific AF trigger. Among the 4 groups, only in Group D (AF at baseline and no PV-specific AF triggers) was arrhythmia-free survival significantly lower in the PVI-alone than PVI-plus arm (P=0.032; hazard ratio 1.68; 95% confidence interval 1.04-2.70). CONCLUSIONS: Patients with sinus rhythm or PV-specific AF triggers did not receive any benefit from substrate ablation, whereas patients with AF and no PV-specific AF trigger benefited from substrate ablation.

Impact of left atrial appendage flow velocity on thrombus resolution and clinical outcomes in patients with atrial fibrillation and silent left atrial thrombi: insights from the LAT study.

AIMS: Blood stasis is crucial in developing left atrial (LA) thrombi. LA appendage peak flow velocity (LAAFV) is a quantitative parameter for estimating thromboembolic risk. However, its impact on LA thrombus resolution and clinical outcomes remains unclear. METHODS AND RESULTS: The LAT study was a multicentre observational study investigating patients with atrial fibrillation (AF) and silent LA thrombi detected by transoesophageal echocardiography (TEE). Among 17 436 TEE procedures for patients with AF, 297 patients (1.7%) had silent LA thrombi. Excluding patients without follow-up examinations, we enrolled 169 whose baseline LAAFV was available. Oral anticoagulation use increased from 85.7% at baseline to 97.0% at the final follow-up (P < 0.001). During 1 year, LA thrombus resolution was confirmed in 130 (76.9%) patients within 76 (34-138) days. Conversely, 26 had residual LA thrombi, 8 had thromboembolisms, and 5 required surgical removal. These patients with failed thrombus resolution had lower baseline LAAFV than those with successful resolution (18.0 [15.8-22.0] vs. 22.2 [17.0-35.0], P = 0.003). Despite limited predictive power (area under the curve, 0.659; P = 0.001), LAAFV ≤ 20.0 cm/s (best cut-off) significantly predicted failed LA thrombus resolution, even after adjusting for potential confounders (odds ratio, 2.72; 95% confidence interval, 1.22-6.09; P = 0.015). The incidence of adverse outcomes including ischaemic stroke/systemic embolism, major bleeding, or all-cause death was significantly higher in patients with reduced LAAFV than in those with preserved LAAFV (28.4% vs. 11.6%, log-rank P = 0.005). CONCLUSION: Failed LA thrombus resolution was not rare in patients with AF and silent LA thrombi. Reduced LAAFV was associated with failed LA thrombus resolution and adverse clinical outcomes.

Characteristic craniofacial defects associated with a novel USP9X truncation mutation.

Germline loss-of-function mutations in USP9X have been reported to cause a wide spectrum of congenital anomalies. Here, we report a Japanese girl with a novel heterozygous nonsense mutation in USP9X who exhibited intellectual disability with characteristic craniofacial abnormalities, including hypotelorism, brachycephaly, hypodontia, micrognathia, severe dental crowding, and an isolated submucous cleft palate. Our findings provide further evidence that disruptions in USP9X contribute to a broad range of congenital craniofacial abnormalities.

Rationale and Design of Prospective, Multicenter, Double-Arm Clinical Trial to Investigate the Efficacy of Tofogliflozin on Left Ventricular Diastolic Dysfunction in Patients with Heart Failure with Preserved Ejection Fraction and Type 2 Diabetes Mellitus (TOP-HFPEF Trial).

BACKGROUND: Recent large clinical trials have revealed that sodium-glucose cotransporter 2 (SGLT2) inhibitors improve cardiovascular outcomes not only in patients with heart failure with reduced ejection fraction, but also in patients with heart failure with mildly reduced or preserved ejection fraction (HFpEF). However, the effect of SGLT2 inhibitors on left ventricular (LV) diastolic function is still controversial. METHODS AND RESULTS: The TOP-HFPEF trial (Efficacy of Tofogliflozin on Left Ventricular Diastolic Dysfunction in Patients with Heart Failure with Preserved Ejection Fraction and Type 2 Diabetes Mellitus) is a multicenter, double-arm, open-label, confirmatory, investigator-initiated clinical study to investigate the effect of SGLT2 inhibitor on LV diastolic function in patients with HFpEF and type 2 diabetes mellitus. The participants are randomly assigned (1:1) to the tofogliflozin group (20 mg once daily) or the control group (administration or continuation of antidiabetic drugs other than SGLT2 inhibitors). The estimated number of patients to be enrolled in this trial is 90 in total (45 in each group). The participants are followed up for 52 weeks with tofogliflozin or control drugs. The primary endpoint is the change in E/e' assessed by echocardiography from the baseline to the end of this study (52 weeks). This trial will also evaluate the effects of tofogliflozin on cardiovascular events, biomarkers, other echocardiographic parameters, the occurrence of atrial fibrillation, and renal function. CONCLUSIONS: The TOP-HFPEF trial will clarify the efficacy of an SGLT2 inhibitor, tofogliflozin, on LV diastolic function in patients with HFpEF and type 2 diabetes mellitus.

Five-Year Transcatheter Aortic Valve Replacement Outcomes in Chronic Hemodialysis vs. Non-Hemodialysis Patients Using Balloon-Expandable Devices.

BACKGROUND: Based on the results of a clinical trial in Japan, transcatheter aortic valve replacement (TAVR) for hemodialysis (HD) patients gained approval; however, mid-term TAVR outcomes and transcatheter aortic valve (TAV) durability in HD patients remain unexplored.Methods and Results: We analyzed background, procedural, in-hospital outcome, and follow-up data for 101 HD patients and 494 non-HD patients who underwent TAVR using balloon-expandable valves (SAPIEN XT or SAPIEN 3) retrieved from Osaka University Hospital TAVR database. Periprocedural mortality and TAVR-related complications were comparable between HD and non-HD patients. However, Kaplan-Meier analysis revealed that HD patients had significantly lower survival rates (log-rank test, P<0.001). In addition, HD patients had significantly higher rates of severe structural valve deterioration (SVD) than non-HD patients (Gray test, P=0.038). CONCLUSIONS: TAVR in HD patients had comparable periprocedural mortality but inferior mid-term survival and TAV durability than in non-HD patients. Indications for TAVR in younger HD patients should be carefully determined, considering the possibility of a TAV-in-TAV procedure when early SVD occurs.

Cardiac sympathetic nerve activity trends after renal denervation in heart failure with preserved ejection fraction.

This case report describes the application of ultrasound renal denervation (uRDN) using the Paradise System in a patient with heart failure with preserved ejection fraction. Initially, the cardiac sympathetic nerve activity of the patient exhibited a late heart/mediastinum (H/M) ratio of 2.00 and a washout rate of 66.0% by cardiac iodine-123 metaiodobenzylguanidine (123I-MIBG) scintigraphy. Subsequently, the patient underwent transfemoral uRDN targeting the left, right upper, and right lower renal arteries. At the 6 month follow-up, no significant change was observed in 123I-MIBG findings; however, the estimated stressed blood volume (eSBV) decreased from 1722 to 1029 mL/70 kg. At 18 months, 123I-MIBG findings improved, with the late H/M ratio reaching 2.76 and the washout rate decreasing to 43.1%. This case report highlights the potential of uRDN in reducing eSBV within 6 months and subsequently improving cardiac sympathetic nerve activity at the 18 month follow-up.

Impact of baseline yellow plaque assessed by coronary angioscopy on vascular response after stent implantation.

BACKGROUND: The relationship between baseline yellow plaque (YP) and vascular response after stent implantation has not been fully investigated. METHODS: This was a sub-analysis of the Collaboration-1 study (multicenter, retrospective, observational study). A total of 88 lesions from 80 patients with chronic coronary syndrome who underwent percutaneous coronary intervention were analyzed. Optical coherence tomography (OCT) and coronary angioscopy (CAS) were serially performed immediately and 11 months after stent implantation. YP was defined as the stented segment with yellow or intensive yellow color assessed by CAS. Neoatherosclerosis was defined as a lipid or calcified neointima assessed by OCT. OCT and CAS findings at 11 months were compared between lesions with baseline YP (YP group) and lesions without baseline YP (Non-YP group). RESULTS: Baseline YP was detected in 37 lesions (42 %). OCT findings at 11 months showed that the incidence of neoatherosclerosis was significantly higher in the YP group (11 % versus 0 %, p = 0.028) and mean neointimal thickness tended to be lower (104 ±â€¯43 µm versus 120 ±â€¯48 µm, p = 0.098). CAS findings at 11 months demonstrated that the dominant and minimum neointimal coverage grades were significantly lower (p = 0.049 and P = 0.026) and maximum yellow color grade was significantly higher (p < 0.001) in the YP group. CONCLUSIONS: Baseline YP affected the incidence of neoatherosclerosis as well as poor neointimal coverage at 11 months after stent implantation.

Current Situation and Consideration of Prefectural Plans for Promotion of Measures Against Cerebrovascular and Cardiovascular Disease in Japan　- Perspectives on Cardiovascular Disease.

In Japan, cerebrovascular diseases and cardiovascular diseases (CVDs) are major causes of death and long-term care. Against this, the Cerebrovascular and Cardiovascular Disease Control Act was passed by a legislative body and promulgated in December 2018, and enacted on December 1, 2019. Based on the Japanese National Plan for Promotion of Measures Against Cerebrovascular and Cardiovascular Disease (Japanese National Plan), prefectural plans have been formulated and published from March 2021 to January 2023. Although the majority of individual measures were comprehensively articulated in accordance with the Japanese National Plan, some prefectures did not describe individual measures such as research, collection of medical information, consultation support for patients with CVD, palliative care, assistance for patients with sequelae, support for maintaining a balance between treatment and work, and measures from childhood and adolescence. Furthermore, a few specific indicators were set for these measures and those related to chronic care. This review identifies the current status of prefectural plans and discusses future challenges and directions.

Twin Study: The Factors Affecting the Serum LDL-C and HDL-C Levels and an RNA-Seq Analysis in Mononuclear Cells in Monozygotic Twins.

AIM: A twin study is a valuable tool for elucidating the acquired factors against lifestyle diseases such as dyslipidemia, diabetes mellitus, and obesity. We aimed 1. to investigate the factors that affect low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) in monozygotic (MZ) twins, and 2. to identify genes which expression levels changed in pairs with large differences in LDL-C or HDL-C levels. METHODS: The registered database at the Center for Twin Research, Osaka University, containing 263 pairs of MZ twins, was analyzed. 1. The effects of smoking, exercise, nutritional factors, and anthropometric and biochemical parameters on LDL-C or HDL-C levels were examined in MZ twins. 2. RNA sequencing in the peripheral blood mononuclear cells of 59 pairs was analyzed for large differences of LDL-C or HDL-C groups. RESULTS: 1. The ΔLDL-C levels were significantly associated with an older age, the ΔTG levels, and ΔBMI. ΔHDL-C levels were associated with the ΔBMI, ΔTG, ΔTP, and ΔLDL-C levels. The HDL-C levels were affected by smoking and exercise habits. The intakes of cholesterol and saturated fatty acids were not associated with the LDL-C or HDL-C levels. 2. An RNA sequencing analysis revealed that the expression of genes related to the TLR4 and IFNG pathways was suppressed in accordance with the HDL-C levels in the larger ΔHDL-C group among the 59 pairs. CONCLUSION: We identified the factors affecting the LDL-C or HDL-C levels in monozygotic twins. In addition, some types of inflammatory gene expression in peripheral blood mononuclear cells were suppressed in accordance with the HDL-C levels, thus suggesting the importance of weight management and exercise habits in addition to dietary instructions to control the LDL-C or HDL-C levels.

Relationship of interleukin-16 with different phenogroups in acute heart failure with preserved ejection fraction.

AIMS: Interleukin-16 (IL-16) has been reported to mediate left ventricular myocardial fibrosis and stiffening in patients with heart failure with preserved ejection fraction (HFpEF). We sought to elucidate whether IL-16 has a distinct impact on pathophysiology and prognosis across different subphenotypes of acute HFpEF. METHODS AND RESULTS: We analysed 211 patients enrolled in a prospective multicentre registry of acute decompensated HFpEF for whom serum IL-16 levels after stabilization were available (53% female, median age 81 [interquartile range 75-85] years). We divided this sub-cohort into four phenogroups using our established clustering algorithm. The study endpoint was all-cause death. Patients were subclassified into phenogroup 1 ('rhythm trouble' [n = 69]), phenogroup 2 ('ventricular-arterial uncoupling' [n = 49]), phenogroup 3 ('low output and systemic congestion' [n = 41]), and phenogroup 4 ('systemic failure' [n = 52]). After a median follow-up of 640 days, 38 patients had died. Among the four phenogroups, phenogroup 2 had the highest IL-16 level. The IL-16 level showed significant associations with indices of cardiac hypertrophy, diastolic dysfunction, and congestion only in phenogroup 2. Furthermore, the IL-16 level had a significant predictive value for all-cause death only in phenogroup 2 (C-statistic 0.750, 95% confidence interval 0.606-0.863, P = 0.017), while there was no association between the IL-16 level and the endpoint in the other phenogroups. CONCLUSIONS: Our results indicated that the serum IL-16 level had a significant association with indices that reflect the pathophysiology and prognosis of HFpEF in a specific phenogroup in acute HFpEF.

Stronger positive correlation of the left ventricular mass index and extracellular volume fraction with diastolic function in diabetic patients without myocardial infarction.

BACKGROUND: The structural and functional characteristics of the heart in patients with diabetes mellitus (DM) and without myocardial infarction (MI) are not fully understood. METHODS: We retrospectively analysed the data of patients with left ventricular ejection fraction (LVEF) ≥ 40% who underwent contrast-enhanced cardiac magnetic resonance imaging (CMR), which was also used to exclude MI, at two hospitals. Volumetric data and extracellular volume fraction (ECVf) of the myocardium evaluated using CMR were compared between patients with and without DM, and their association with diastolic function was evaluated. RESULTS: Among 322 analysed patients, 53 had DM. CMR revealed that the left ventricular mass index (LVMi) and ECVf were increased while LVEF was decreased in patients with DM after adjusting for patient characteristics (all P < 0.05). A stronger positive correlation was observed between LVMi and the early diastolic transmitral flow velocity to early diastolic mitral annular velocity ratio (E/e') in patients with DM than in those without DM (correlation coefficient [R] = 0.46, p = 0.001; R = 0.15, p = 0.021, respectively; p for interaction = 0.011). ECVf correlated with E/e' only in patients with DM (R = 0.61, p = 0.004). CONCLUSIONS: Patients with DM have increased LVMi and ECVf. Importantly, there was a difference between patients with and without DM in the relationship between these structural changes and E/e', with a stronger relationship in patients with DM. Furthermore, DM is associated with mildly reduced LVEF even in the absence of MI.

Lower doses of carvedilol in Japanese heart failure patients with reduced ejection fraction could show the potential to be non-inferior to higher doses in US patients: An international collaborative observational study.

The Japanese national guidelines recommend significantly lower doses of carvedilol for heart failure with reduced ejection fraction (HFrEF) management than the US guidelines. Using real-world data, we determined whether initial and target doses of carvedilol in Japanese patients (JPNs) differ from those in US patients (USPs), especially in Asian Americans (ASA) and Caucasians (CA), and investigated differences in outcomes. We collected data from the electronic medical records, including demographics, carvedilol dosing, tolerability, cardiac functional indicators like EF, cardiovascular events including all-cause deaths, and laboratory values from the University of California, San Diego Health and Osaka University. JPNs had significantly lower doses (mg/day) of carvedilol initiation (66 USPs composed of 38 CAs and 28 ASAs, 17.1±16.2; 93 JPNs, 4.3±4.2, p<0.001) and one year after initiation (33.0±21.8; 11.2±6.5, p<0.001), and a significantly lower relative rate (RR) of dose discontinuation and reduction than USPs (RR: 0.406, 95% confidence interval (CI): 0.181-0.911, p<0.05). CAs showed the highest reduction rate (0.184), and ASAs had the highest discontinuation rate (0.107). A slight mean difference with narrow 95% CI ranges straddling zero was observed between the two regions in the change from the baseline of each cardiac functional indicator (LVEF, -0.68 [-5.49-4.12]; LVDd, -0.55 [-3.24-2.15]; LVDd index, -0.25 [-1.92-1.43]; LVDs, -0.03 [-3.84-3.90]; LVDs index, -0.04 [-2.38-2.30]; heart rate, 1.62 [-3.07-6.32]). The event-free survival showed no difference (p = 0.172) among the races. Conclusively, despite JPNs exhibiting markedly lower carvedilol doses, their dose effectiveness has the potential to be non-inferior to that in USPs. Dose de-escalation, not discontinuation, could be an option in some Asian and ASA HFrEF patients intolerable to high doses of carvedilol.

Three-year clinical course after fluoropolymer-based drug-eluting stent implantation for femoropopliteal lesions.

BACKGROUND: Although the 1-year clinical outcomes of fluoropolymer-based drug-eluting stents (FP-DES) were favorable for the treatment of real-world femoropopliteal lesions in symptomatic peripheral artery disease (PAD), their performance beyond 1 year remained unknown. The current study determined the 3-year clinical course of FP-DES implantation for real-world femoropopliteal lesions. METHODS: This multicenter, prospective, observational study evaluated 1204 limbs (chronic limb-threatening ischemia, 34.8%; mean lesion length, 18.6 ± 9.9 cm, chronic total occlusion: 53.2%) of 1097 patients with PAD (age, 75 ± 9 years; diabetes mellitus, 60.8%) undergoing FP-DES implantation for femoropopliteal lesions. The primary outcome measure was 3-year restenosis. The secondary outcome measures included 3-year occlusive restenosis, stent thrombosis, target lesion revascularization (TLR), and aneurysmal degeneration. RESULTS: The 3-year cumulative occurrence of restenosis was 27.3%, whereas that of occlusive restenosis, stent thrombosis, and TLR was 16.1%, 7.3%, and 19.6%, respectively. The annual occurrence of restenosis decreased by 12.0%, 9.5%, and 5.8% in the first, second, and third year, respectively (p < 0.001). Similarly, the rates of occlusive restenosis and stent thrombosis decreased (p < 0.001 and p = 0.007, respectively), whereas the rate of TLR remained unchanged for 3 years (p = 0.15). The incidence of aneurysmal degeneration at 3 years (15.7%) did not significantly differ from that at 1 and 2 years (p = 0.69 and 0.20, respectively). CONCLUSIONS: This study highlights the favorable long-term clinical course of FP-DES in real-world practice, emphasizing the importance of monitoring for occlusive restenosis and stent thrombosis while considering the potential onset of aneurysmal degeneration.

Novel indices representing heterogeneous distributions of myocardial perfusion imaging.

INTRODUCTION: Heterogeneous distribution in myocardial perfusion images (MPI) obtained by scintigraphy is often observed in cardiac diseases with normal myocardial perfusion. However, quantitative assessments of such heterogeneity have not been established. We hypothesized that the heterogeneity in MPI can be quantitatively evaluated through histogram analysis, calculating the standard deviation (SD), the 95% bandwidth (BW95%), and entropy. METHODS: We examined resting 99mTc-MIBI images in 20 healthy subjects and 29 patients with cardiac disease who had none or very-mild reduced myocardial perfusion evaluated as a low summed rest score (0 to 4, the range of the studied healthy subjects). Two nuclear medicine specialists blindly divided them into two groups: non-heterogeneity or heterogeneity group, based solely on their visual assessments of heterogeneity on splash and polar maps generated from single-photon emission computed tomography (SPECT) images. The %uptake was determined by dividing the tracer count of each pixel by the tracer count of the pixel with the highest value in the LV myocardium. SD, BW95%, and entropy from histogram patterns were analyzed from the polar map data array of each %uptake. We investigated whether heterogeneity could be assessed using SD, BW95, and entropy in two groups classified by visual assessments. Additionally, we evaluated the area under the curve (AUC) to identify heterogeneity in the receiver operating characteristic curve analysis. RESULTS: Based solely on visual assessments, 11 (22%) and 38 (78%) cases were classified into the non-heterogeneity and heterogeneity groups, respectively. The non-heterogeneity group consisted of only healthy subjects, and all patients with cardiac disease were classified into the heterogeneity group. The cases in the heterogeneity group had significantly higher values of heterogeneity indices (SD, BW95%, and entropy) in %uptake than those in the non-heterogeneity group (p < 0.05 for all). The AUCs of the heterogeneity indices were sufficiently high (AUCs > 0.90 for all) in distinguishing cases with visually heterogeneous distribution or patients with cardiac disease. CONCLUSIONS: Heterogeneity in MPI can be evaluated using SD, BW95%, and entropy through histogram analysis. These novel indices may help identify patients with subtle myocardial changes, even in images that show preserved perfusion (345/350).