著者
Hisashi Kai Takeshi Kimura Kenji Fukuda Yoshihiro Fukumoto Tatsuyuki Kakuma Yutaka Furukawa on behalf of CREDO-Kyoto Investigators
出版者
日本循環器学会
雑誌
Circulation Journal (ISSN:13469843)
巻号頁・発行日
pp.CJ-15-1151, (Released:2016-04-06)
参考文献数
21
被引用文献数
3

Background:We investigated the effects of age and low diastolic blood pressure (DBP) on cardiovascular death in patients with coronary artery disease (CAD) after coronary revascularization.Methods and Results:Stable, chronic CAD patients after coronary revascularization in the CREDO-Kyoto registry cohort-1 were allocated to the Young (≤64 years, n=2,619), Young-Old (65–74 years, n=2,932), and Old-Old (≥75 years, n=1,629) groups. Kaplan-Meier analysis showed that the crude cumulative incidence of cardiovascular death was higher in Young-Old patients with DBP <70 mmHg (P<0.001) and in Old-Old patients with DBP <60 mmHg (P=0.017), but not <70 mmHg (P=0.629), compared with each counterpart. Low DBP did not increase cardiovascular death in young patients. After adjustments with independent predictors, DBP <60 mmHg did not increase the cardiovascular death in the Old-Old group (HR=1.579 [95% CI, 0.944–2.642], P=0.082) and DBP <70 mmHg remained a predictor in the Young-Old group (HR=1.665 [1.094–2.532], P=0.017). On multivariate stepwise Cox proportional hazard regression analysis, independent predictors for cardiovascular death in low DBP patients were creatinine clearance (CCr; inversely), prior cerebrovascular disease, and aortic disease in the Young-Old group and CCr (inversely) and malignancy in the Old-Old group.Conclusions:DBP <60 mmHg was not an independent factor for predicting cardiovascular death in Old-Old revascularized CAD patients, whereas DBP <70 mmHg remained a predictor in the Young-Old.
著者
Shigeru Saito Takaaki Isshiki Takeshi Kimura Hisao Ogawa Hiroyoshi Yokoi Shinsuke Nanto Morimasa Takayama Kazuo Kitagawa Masakatsu Nishikawa Shunichi Miyazaki Masato Nakamura
出版者
日本循環器学会
雑誌
Circulation Journal (ISSN:13469843)
巻号頁・発行日
vol.78, no.7, pp.1684-1692, 2014 (Released:2014-06-25)
参考文献数
14
被引用文献数
44 91

Background: Prasugrel is an antiplatelet agent that shows more prompt, potent, and consistent platelet inhibition than clopidogrel. The objective of this study was to confirm the efficacy and safety of prasugrel at loading/maintenance doses of 20/3.75mg. Methods and Results: Japanese patients (n=1,363) with acute coronary syndrome undergoing percutaneous coronary intervention were randomized to either prasugrel (20/3.75mg) or clopidogrel (300/75mg), both in combination with aspirin (81–330mg for the first dose and 81–100mg/day thereafter), for 24–48 weeks. The primary efficacy endpoint was the incidence of major adverse cardiovascular events (MACE) at 24 weeks, defined as a composite of cardiovascular death, nonfatal myocardial infarction, and nonfatal ischemic stroke. We compared the incidence of MACE between the 2 groups using point estimates. Safety outcomes included the incidence of bleeding events until 2 weeks after the last dose. The incidence of MACE at 24 weeks was 9.4% in the prasugrel group and 11.8% in the clopidogrel group (risk reduction 23%, hazard ratio 0.77, 95% confidence interval 0.56–1.07). The incidence of non-coronary artery bypass graft-related major bleeding was similar in both groups (1.9% vs. 2.2%). Conclusions: Prasugrel 20/3.75mg was associated with a low incidence of ischemic events, similar to the results of TRITON-TIMI 38, and with a low risk of clinically serious bleeding in Japanese ACS patients.  (Circ J 2014; 78: 1684–1692)
著者
Kenji Nakatsuma Hiroki Shiomi Takeshi Morimoto Yutaka Furukawa Yoshihisa Nakagawa Kenji Ando Kazushige Kadota Takashi Yamamoto Satoru Suwa Minoru Horie Takeshi Kimura on behalf of the CREDO-Kyoto AMI investigators
出版者
日本循環器学会
雑誌
Circulation Journal (ISSN:13469843)
巻号頁・発行日
pp.CJ-16-0204, (Released:2016-06-28)
参考文献数
24
被引用文献数
2 5

Background:Inter-facility transfer for primary percutaneous coronary intervention (PCI) from referring facilities to PCI centers causes a significant delay in treatment of ST-segment elevation acute myocardial infarction (STEMI) patients undergoing primary PCI. However, little is known about the clinical outcomes of STEMI patients undergoing inter-facility transfer in Japan.Methods and Results:In the CREDO-Kyoto acute myocardial infarction (AMI) registry that enrolled 5,429 consecutive AMI patients in 26 centers in Japan, the current study population consisted of 3,820 STEMI patients who underwent primary PCI within 24 h of symptom onset. We compared long-term clinical outcomes between inter-facility transfer patients and those directly admitted to PCI centers. The primary outcome measure was a composite of all-cause death or heart failure (HF) hospitalization. There were 1,725 (45.2%) inter-facility transfer patients, and 2,095 patients (54.8%) with direct admission to PCI centers. The cumulative 5-year incidence of death/HF hospitalization was significantly higher in the inter-facility transfer patients than in those with direct admission (26.9% vs. 22.2%; log-rank P<0.001). After adjusting for potential confounders, the risk for death/HF hospitalization was significantly higher (adjusted hazard ratio: 1.22, 95% confidence interval: 1.07–1.40, P<0.001) in the inter-facility transfer patients than in those directly admitted.Conclusions:Inter-facility transfer was associated with significantly worse long-term clinical outcomes for patients with STEMI undergoing primary PCI.
著者
Kenji Nakatsuma Hiroki Shiomi Takeshi Morimoto Kenji Ando Kazushige Kadota Hiroki Watanabe Tomohiko Taniguchi Takashi Yamamoto Yutaka Furukawa Yoshihisa Nakagawa Minoru Horie Takeshi Kimura on behalf of the CREDO-Kyoto AMI investigators
出版者
日本循環器学会
雑誌
Circulation Journal (ISSN:13469843)
巻号頁・発行日
pp.CJ-15-0870, (Released:2015-12-15)
参考文献数
19
被引用文献数
2 6

Background:In the setting of elective percutaneous coronary intervention (PCI), intravascular ultrasound (IVUS)-guided PCI is associated with a reduction in the incidence of target vessel revascularization (TVR), but the impact of IVUS on long-term clinical outcome in the setting of emergency PCI for ST-segment elevation acute myocardial infarction (STEMI) is still unclear.Methods and Results:The subjects consisted of 3,028 STEMI patients who underwent primary PCI within 24 h of symptom onset in the CREDO-Kyoto acute myocardial infarction registry. Of these, 932 patients (31%) underwent IVUS-guided PCI. Compared with the angiography-guided PCI without IVUS, IVUS-guided PCI was associated with significantly lower incidences of TVR (primary outcome measure; 22% vs. 27%, log-rank P<0.001) and definite stent thrombosis (ST; 1.2% vs. 3.1%, log-rank P=0.003). The cumulative incidence of all-cause death was not significantly different between the 2 groups. After adjusting for confounders, however, there were no significant differences between the 2 groups in risk for TVR (adjusted HR, 1.14; 95% CI: 0.86–1.51, P=0.38) and definite ST (adjusted HR, 0.58; 95% CI: 0.19–1.72, P=0.33).Conclusions:IVUS-guided PCI was not associated with a lower risk for TVR or ST in STEMI patients undergoing primary PCI.
著者
Shinya Goto Chien-Hua Huang Seung-Jung Park Håkan Emanuelsson Takeshi Kimura
出版者
日本循環器学会
雑誌
Circulation Journal (ISSN:13469843)
巻号頁・発行日
pp.CJ-15-0112, (Released:2015-09-16)
参考文献数
37
被引用文献数
9 41

Background:Few data on the relative efficacy and safety of new P2Y12inhibitors such as prasugrel and ticagrelor in Japanese, Taiwanese and South Korean patients with acute coronary syndromes (ACS) exist.Methods and Results:The multicenter, double-blind, randomized PHILO trial compared the safety and efficacy of ticagrelor vs. clopidogrel in 801 patients with ACS (Japanese, n=721; Taiwanese, n=35; South Korean, n=44; unknown ethnicity, n=1). All were planned to undergo percutaneous coronary intervention and randomized within 24 h of symptom onset. Primary safety and efficacy endpoints were time to first occurrence of any major bleeding event and to any event from the composite of myocardial infarction, stroke or death from vascular causes, respectively.At 12 months, overall major bleeding occurred in 10.3% of ticagrelor-treated patients and in 6.8% of clopidogrel-treated patients (hazard ratio (HR), 1.54; 95% confidence interval (CI): 0.94–2.53); the composite primary efficacy endpoint occurred in 9.0% and in 6.3% of ticagrelor- and clopidogrel-treated patients, respectively (HR, 1.47; 95% CI: 0.88–2.44). For both analyses, the difference between groups was not statistically significant.Conclusions:In ACS patients from Japan, Taiwan and South Korea, event rates of primary safety and efficacy endpoints were higher, albeit not significantly, in ticagrelor-treated patients compared with clopidogrel-treated patients. This observation could be explained by the small sample size, imbalance in clinical characteristics and low number of events in the PHILO population.
著者
Mamoru Hayano Takeru Makiyama Tsukasa Kamakura Hiroshi Watanabe Kenichi Sasaki Shunsuke Funakoshi Yimin Wuriyanghai Suguru Nishiuchi Takeshi Harita Yuta Yamamoto Hirohiko Kohjitani Sayako Hirose Fumika Yokoi Jiarong Chen Osamu Baba Takahiro Horie Kazuhisa Chonabayashi Seiko Ohno Futoshi Toyoda Yoshinori Yoshida Koh Ono Minoru Horie Takeshi Kimura
出版者
日本循環器学会
雑誌
Circulation Journal (ISSN:13469843)
巻号頁・発行日
pp.CJ-17-0064, (Released:2017-06-20)
参考文献数
38
被引用文献数
5

Background:TheSCN5Agene encodes the α subunit of the cardiac voltage-gated sodium channel, NaV1.5. The missense mutation, D1275N, has been associated with a range of unusual phenotypes associated with reduced NaV1.5 function, including cardiac conduction disease and dilated cardiomyopathy. Curiously, the reported biophysical properties ofSCN5A-D1275N channels vary with experimental system.Methods and Results:First, using a human embryonic kidney (HEK) 293 cell-based heterologous expression system, theSCN5A-D1275N channels showed similar maximum sodium conductance but a significantly depolarizing shift of activation gate (+10 mV) compared to wild type. Second, we generated human-induced pluripotent stem cells (hiPSCs) from a 24-year-old female who carried heterozygousSCN5A-D1275N and analyzed the differentiated cardiomyocytes (CMs). AlthoughSCN5Atranscript levels were equivalent between D1275N and control hiPSC-CMs, both the total amount of NaV1.5 and the membrane fractions were reduced approximately half in the D1275N cells, which were rescued by the proteasome inhibitor MG132 treatment. Electrophysiological assays revealed that maximum sodium conductance was reduced to approximately half of that in control hiPSC-CMs in the D1275N cells, and maximum upstroke velocity of action potential was lower in D1275N, which was consistent with the reduced protein level of NaV1.5.Conclusions:This study successfully demonstrated diminished sodium currents resulting from lower NaV1.5 protein levels, which is dependent on proteasomal degradation, using a hiPSC-based model forSCN5A-D1275N-related sodium channelopathy.
著者
Mamoru Toyofuku Tomohiko Taniguchi Takeshi Morimoto Kyohei Yamaji Yutaka Furukawa Kosuke Takahashi Takashi Tamura Hiroki Shiomi Kenji Ando Norio Kanamori Koichiro Murata Takeshi Kitai Yuichi Kawase Chisato Izumi Makoto Miyake Hirokazu Mitsuoka Masashi Kato Yutaka Hirano Shintaro Matsuda Tsukasa Inada Tomoyuki Murakami Yasuyo Takeuchi Keiichiro Yamane Mitsuru Ishii Eri Minamino-Muta Takao Kato Moriaki Inoko Tomoyuki Ikeda Akihiro Komasa Katsuhisa Ishii Kozo Hotta Nobuya Higashitani Yoshihiro Kato Yasutaka Inuzuka Chiyo Maeda Toshikazu Jinnai Yuko Morikami Naritatsu Saito Kenji Minatoya Takeshi Kimura on behalf of the CURRENT AS Registry Investigators
出版者
日本循環器学会
雑誌
Circulation Journal (ISSN:13469843)
巻号頁・発行日
pp.CJ-16-1244, (Released:2017-04-08)
参考文献数
23
被引用文献数
4

Background:There is a paucity of data on the sex differences in the prevalence, clinical presentation, and prognosis of aortic stenosis (AS).Methods and Results:A total of 3,815 consecutive patients with severe AS were enrolled in the multicenter CURRENT AS registry between January 2003 and December 2011. The registry included 1,443 men (38%) and 2,372 women (62%). Women were much older than men (79±10 vs. 75±10 years, P<0.0001), and the ratio of women to men increased with age. The cumulative 5-year incidence of all-cause death was significantly higher in men than in women (47% vs. 41%, P=0.003), although women were more symptomatic and much older. The 5-year mortality was similar between men and women at age <65 years (16% vs. 15%, P=0.99), whereas it was significantly higher in men than in women at age ≥65 years (65–74 years, 38% vs. 19%, P<0.0001; 75–84 years, 55% vs. 34%, P<0.0001; ≥85 years: 82% vs. 72%, P=0.03).Conclusions:A large Japanese multicenter registry of consecutive patients with severe AS included a much higher proportion of women than men, with the female:male sex ratio increasing with age. The 5-year mortality rate of women was lower than that of men. Lower 5-year mortality rates in women were consistently seen across all age groups >65 years.
著者
Toshiaki Toyota Takeshi Morimoto Hiroki Shiomi Kenji Ando Koh Ono Satoshi Shizuta Takao Kato Naritatsu Saito Yutaka Furukawa Yoshihisa Nakagawa Minoru Horie Takeshi Kimura on behalf of the CREDO-Kyoto PCI/CABG Registry Cohort-2 Investigators
出版者
日本循環器学会
雑誌
Circulation Journal (ISSN:13469843)
巻号頁・発行日
pp.CJ-16-0987, (Released:2017-02-07)
参考文献数
31
被引用文献数
2

Background:Few studies have evaluated the prevalence and clinical outcomes of ad hoc percutaneous coronary intervention (PCI), performing diagnostic coronary angiography and PCI in the same session, in stable coronary artery disease (CAD) patients.Methods and Results:From the CREDO-Kyoto PCI/CABG registry cohort-2, 6,943 patients were analyzed as having stable CAD and undergoing first PCI. Ad hoc PCI and non-ad hoc PCI were performed in 1,722 (24.8%) and 5,221 (75.1%) patients, respectively. The cumulative 5-year incidence and adjusted risk for all-cause death were not significantly different between the 2 groups (15% vs. 15%, P=0.53; hazard ratio: 1.15, 95% confidence interval: 0.98–1.35, P=0.08). Ad hoc PCI relative to non-ad hoc PCI was associated with neutral risk for myocardial infarction, any coronary revascularization, and bleeding, but was associated with a trend towards lower risk for stroke (hazard ratio: 0.78, 95% confidence interval: 0.60–1.02, P=0.06).Conclusions:Ad hoc PCI in stable CAD patients was associated with at least comparable 5-year clinical outcomes as with non-ad hoc PCI. Considering patients’ preference and the cost-saving, the ad hoc PCI strategy might be a safe and attractive option for patients with stable CAD, although the prevalence of ad hoc PCI was low in the current study population.
著者
Hideo Sasai Nobuyuki Shimozawa Takahiko Asano Norio Kawamoto Takahiro Yamamoto Takeshi Kimura Minako Kawamoto Eiko Matsui Toshiyuki Fukao
出版者
東北ジャーナル刊行会
雑誌
The Tohoku Journal of Experimental Medicine (ISSN:00408727)
巻号頁・発行日
vol.237, no.4, pp.323-327, 2015 (Released:2015-12-04)
参考文献数
11
被引用文献数
2 4

Cystathionine β-synthase (CBS) deficiency, well known as classical homocystinuria, is a rare autosomal recessive inborn error of homocysteine and sulfur metabolism. CBS converts homocysteine to cystathionine. The clinical features of untreated CBS deficiency include myopia, ectopia lentis, mental retardation, skeletal anomalies resembling Marfan syndrome, and thromboembolic events. Cerebral white matter lesions (CWMLs), identified in magnetic resonance imaging (MRI), are related to various clinical conditions including ischemia, inflammation, demyelination, infection, a tumor, and metabolic disorders such as phenylketonuria. The presence of CWMLs is, however, believed to be a very rare condition in CBS-deficient patients. Herein, we report reversible CWMLs associated with hypermethioninemia caused by poor protein restriction and betaine therapy in a 21-year-old male with pyridoxine-nonresponsive CBS deficiency. T2-weighted images (T2WI) and fluid-attenuated inversion-recovery (FLAIR) images showed diffuse high signal intensity in subcortical areas extending to the deep white matter. Diffusion-weighted images (DWI) showed high signal intensity, while apparent diffusion coefficient (ADC) map demonstrated decreased ADC value in the lesions. The course of improvement after correct methionine restriction was successively followed by brain MRI. The CWMLs had regressed at 1 month after restriction, and disappeared after 5 months. ADC values were very low before proper methionine restriction, but normalized after 2 months. Use of betaine in the presence of elevated plasma methionine may increase the risk of reversible CWMLs in some CBS-deficient patients.
著者
Hiroaki Takashima Yukio Ozaki Takeshi Morimoto Takeshi Kimura Takafumi Hiro Katsumi Miyauchi Yoshihisa Nakagawa Masakazu Yamagishi Hiroyuki Daida Tomofumi Mizuno Kenji Asai Yasuo Kuroda Takashi Kosaka Yasushi Kuhara Akiyoshi Kurita Kazuyuki Maeda Tetsuya Amano Masunori Matsuzaki for the JAPAN-ACS Investigators
出版者
日本循環器学会
雑誌
Circulation Journal (ISSN:13469843)
巻号頁・発行日
vol.76, no.12, pp.2840-2847, 2012 (Released:2012-11-22)
参考文献数
32
被引用文献数
4 5

Background: The JAPAN-ACS (Japan Assessment of Pitavastatin and Atorvastatin in Acute Coronary Syndrome) trial showed that intensive statin therapy could induce significant coronary plaque regression in acute coronary syndrome (ACS). We evaluated the impact of metabolic syndrome (MetS) and its components on coronary plaque regression in the JAPAN-ACS patients. Methods and Results: Serial intravascular ultrasound measurements over 8–12 months were performed in 242 ACS patients receiving pitavastatin or atorvastatin. Patients were divided into groups according to the presence of MetS or the number of MetS components. Although the percent change in plaque volume (%PV) was not significantly different between the MetS (n=119) and non-MetS (n=123) groups (P=0.50), it was significantly associated with an increasing number of MetS components (component 0: −24.0%, n=7; components 1: −20.8%, n=31; components 2: −16.1%, n=69; components 3: −18.7%, n=83; components 4: −13.5%, n=52; P=0.037 for trend). The percent change in body mass index (%BMI) significantly correlated with %PV (r=0.15, P=0.021), especially in the MetS components 4 group (r=0.35, P=0.017). In addition, %BMI was an independent predictor of plaque regression after adjustment for the changes of low- and high-density lipoprotein cholesterol, triglycerides and HbA1c. Conclusions: The clustering of MetS components, but not the presence of MetS itself, could attenuate coronary plaque regression during intensive statin therapy in ACS patients. Therefore, to achieve a greater degree of plaque regression, it is necessary to treat to each MetS component and use lifestyle modification.  (Circ J 2012; 76: 2840–2847)
著者
Hiroki Shiomi Takeshi Morimoto Yutaka Furukawa Yoshihisa Nakagawa Ryuzo Sakata Hitoshi Okabayashi Michiya Hanyu Mitsuomi Shimamoto Noboru Nishiwaki Tatsuhiko Komiya Takeshi Kimura on behalf of the CREDO-Kyoto PCI/CABG registry cohort-2 investigators
出版者
日本循環器学会
雑誌
Circulation Journal (ISSN:13469843)
巻号頁・発行日
pp.CJ-15-0034, (Released:2015-03-30)
参考文献数
23
被引用文献数
9 22

Background:Studies evaluating long-term (≥5 years) outcome of percutaneous coronary intervention (PCI) compared with coronary artery bypass grafting (CABG) in patients with unprotected left main coronary artery disease (ULMCAD) are still limited, despite concerns for late adverse events after drug-eluting stents implantation.Methods and Results:We identified 1,004 patients with ULMCAD (PCI: n=364, CABG: n=640) among 15,939 patients with first coronary revascularization enrolled in the CREDO-Kyoto PCI/CABG registry cohort-2. The primary outcome measure in the current analysis was a composite of death, myocardial infarction, and stroke (death/MI/stroke). The cumulative 5-year incidence of and the adjusted risk for death/MI/stroke were significantly higher in the PCI group than in the CABG group (34.5% vs. 24.1%, log-rank P<0.001, adjusted hazard ratio (HR): 1.48 [95% confidence interval (CI): 1.07–2.05, P=0.02]). The adjusted risks for all-cause death was not significantly different between the 2 groups. Regarding the stratified analysis by the SYNTAX score, the adjusted risk for death/MI/stroke was not significantly different between the 2 groups in patients with low (<23) or intermediate (23–33) SYNTAX score, whereas it was significantly higher in the PCI group than in the CABG group in patients with high (≤33) SYNTAX score.Conclusions:CABG as compared with PCI was associated with better long-term outcome in patients with ULMCAD, especially those with high anatomical complexity.
著者
Toru Miyoshi Kazuhiro Osawa Hiroshi Ito Susumu Kanazawa Takeshi Kimura Hiroki Shiomi Sachio Kuribayashi Masahiro Jinzaki Akio Kawamura Hiram Bezerra Stephan Achenbach Bjarne L. Nørgaard
出版者
日本循環器学会
雑誌
Circulation Journal (ISSN:13469843)
巻号頁・発行日
vol.79, no.2, pp.406-412, 2015-01-23 (Released:2015-01-23)
参考文献数
29
被引用文献数
5 13

Background:Recently, a non-invasive method using computational fluid dynamics to calculate vessel-specific fractional flow reserve (FFRCT) from routinely acquired coronary computed tomography angiography (CTA) was described. The Analysis of Coronary Blood Flow Using CT Angiography: Next Steps (NXT) trial, which was a prospective, multicenter trial including 254 patients with suspected coronary artery disease, noted high diagnostic performance of FFRCTcompared with invasive FFR. The aim of this post-hoc analysis was to assess the diagnostic performance of non-invasive FFRCTvs. standard stenosis quantification on coronary CTA in the Japanese subset of the NXT trial.Methods and Results:A total of 57 Japanese participants were included from Okayama University (n=36), Kyoto University (n=17), and Keio University (n=4) Hospitals. Per-patient diagnostic accuracy of FFRCT(74%; 95% confidence interval [CI]: 60–85%) was higher than for coronary CTA (47%; 95% CI: 34–61%, P<0.001) arising from improved specificity (63% vs. 27%, P<0.001). FFRCTcorrectly reclassified 53% of patients and 63% of vessels with coronary CTA false positives as true negatives. When patients with Agatston score >1,000 were excluded, per-patient accuracy of FFRCTwas 83% with a high specificity of 76%, similar to the overall NXT trial findings.Conclusions:FFRCThas high diagnostic performance compared with invasive FFR in the Japanese subset of patients in the NXT trial. (Circ J 2015; 79: 406–412)
著者
Tsukasa Kamakura Takeru Makiyama Kenichi Sasaki Yoshinori Yoshida Yimin Wuriyanghai Jiarong Chen Tetsuhisa Hattori Seiko Ohno Toru Kita Minoru Horie Shinya Yamanaka Takeshi Kimura
出版者
日本循環器学会
雑誌
Circulation Journal (ISSN:13469843)
巻号頁・発行日
pp.CJ-12-0987, (Released:2013-02-09)
参考文献数
34
被引用文献数
28 72

Background: In the short- to mid-term, cardiomyocytes generated from human-induced pluripotent stem cells (hiPSC-CMs) have been reported to be less mature than those of adult hearts. However, the maturation process in a long-term culture remains unknown. Methods and Results: A hiPSC clone generated from a healthy control was differentiated into CMs through embryoid body (EB) formation. The ultrastructural characteristics and gene expressions of spontaneously contracting EBs were analyzed through 1-year of culture after cardiac differentiation was initiated. The 14-day-old EBs contained a low number of myofibrils, which lacked alignment, and immature high-density Z-bands lacking A-, H-, I-, and M-bands. Through the long-term culture up to 180 days, the myofibrils became more tightly packed and formed parallel arrays accompanied by the appearance of mature Z-, A-, H-, and I-bands, but not M-bands. Notably, M-bands were finally detected in 360-day-old EBs. The expression levels of the M-band-specific genes in hiPSC-CMs remained lower in comparison with those in the adult heart. Immunocytochemistry indicated increasing number of MLC2v-positive/MLC2a-negative cells with decreasing number of MLC2v/MLC2a double-positive cells, indicating maturing of ventricular-type CMs. Conclusions: The structural maturation process of hiPSC-CMs through 1-year of culture revealed ultrastructural sarcomeric changes accompanied by delayed formation of M-bands. Our study provides new insight into the maturation process of hiPSC-CMs.