著者

Satoshi Oka Yusuke Watanabe Masashi Amano Tsukasa Kamakura Chisato Izumi Kengo Kusano

出版者

The Japanese Circulation Society

雑誌

Circulation Reports (ISSN:24340790)

巻号頁・発行日

pp.CR-23-0052, (Released:2023-08-09)

参考文献数

1

著者

Nobuhiko Ueda Takashi Noda Koshiro Kanaoka Yuichiro Miyazaki Akinori Wakamiya Kenzaburo Nakajima Tsukasa Kamakura Mitsuru Wada Kenichiro Yamagata Kohei Ishibashi Yuko Inoue Koji Miyamoto Satoshi Nagase Takeshi Aiba Hideaki Kanzaki Chisato Izumi Teruo Noguchi Satoshi Yasuda Kengo Kusano

出版者

The Japanese Circulation Society

雑誌

Circulation Journal (ISSN:13469843)

巻号頁・発行日

pp.CJ-23-0547, (Released:2023-12-05)

参考文献数

27

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Background: Atrial tachyarrhythmias (ATAs) are reportedly associated with ventricular arrhythmias (VAs). However, little is known about the association between ATA duration and the risk of VA. We investigated the relationship between ATA duration and subsequent VA in patients with a cardiac resynchronization therapy defibrillator (CRT-D).Methods and Results: We investigated associations between the longest ATA duration during the first year after cardiac resynchronization therapy (CRT) implantation and VA and VA relevant to ATA (VAATA) in 160 CRT-D patients. ATAs occurred in 63 patients in the first year. During a median follow-up of 925 days from 1 year after CRT implantation, 40 patients experienced 483 VAs. Kaplan-Meier analysis showed a significantly higher risk of VA in patients with than without ATA in the first year (log rank P=0.0057). Hazard ratios (HR) of VA (HR 2.36, 2.10, and 3.04 for ATA >30s, >6 min and >24 h, respectively) and only VAATA (HR 4.50, 5.59, and 11.79 for ATA >30s, >6 min and >24 h, respectively) increased according to the duration of ATA. In multivariate analysis, ATA >24 h was an independent predictor of subsequent VA (HR 2.42; P=0.02).Conclusions: Patients with ATA >24 h in the first year after CRT had a higher risk of subsequent VA and VAATA. The risk of VA, including VAATA, increased with the longest ATA duration.

著者

Tomomi Nagayama Satoshi Nagase Tsukasa Kamakura Mitsuru Wada Kohei Ishibashi Yuko Y. Inoue Koji Miyamoto Takashi Noda Takeshi Aiba Hiroshi Takaki Masaru Sugimachi Wataru Shimizu Teruo Noguchi Satoshi Yasuda Shiro Kamakura Kengo Kusano

出版者

The Japanese Circulation Society

雑誌

Circulation Journal (ISSN:13469843)

巻号頁・発行日

pp.CJ-18-0643, (Released:2019-01-12)

参考文献数

38

被引用文献数

7

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Background: Spontaneous type 1 electrocardiogram (ECG) in the right precordial lead is a dominant predictor of ventricular fibrillation (VF) in Brugada syndrome (BrS). In some BrS patients with VF, however, spontaneous type 1 ECG is undetectable, even in repeated ECG and immediately after VF. This study investigated differences between BrS patients with spontaneous or drug-induced type 1 ECG. Methods and Results: We evaluated 15 BrS patients with drug-induced (D-BrS) and 29 with spontaneous type 1 ECG (SP-BrS). All patients had had a previous VF episode. In each D-BrS patient, ECG was recorded more than 15 times (mean, 46±34) during 7.2±5.1 years of follow-up. Age and family history were comparable between groups. Inferolateral early repolarization (ER) was observed in 13 D-BrS (87%) at least once but in only 3 SP-BrS (10%, P<0.01). Immediately after VF, inferolateral ER was accentuated in 9 of 10 D-BrS, while type 1 ECG was accentuated in 12 of 16 SP-BrS. Fragmented QRS in the right precordial lead and aVR sign were absent in D-BrS but present in 20 (69%, P<0.01) and 11 (38%, P<0.01) SP-BrS, respectively. There was no prognostic difference between groups. Conclusions: Although having similar clinical profiles, there are obvious ECG differences between VF-positive BrS patients with spontaneous or drug-induced type 1 ECG. The inferolateral lead rather than the right precordial lead on ECG may be particularly crucial in some BrS patients.

著者

Hiroyuki Kamada Kazuki Mori Nobuhiko Ueda Akinori Wakamiya Kenzaburo Nakajima Tsukasa Kamakura Mitsuru Wada Kohei Ishibashi Kenichiro Yamagata Yuko Inoue Koji Miyamoto Satoshi Nagase Takashi Noda Chisato Izumi Teruo Noguchi Kengo Kusano Takeshi Aiba

出版者

International Heart Journal Association

雑誌

International Heart Journal (ISSN:13492365)

巻号頁・発行日

vol.63, no.5, pp.828-836, 2022-09-30 (Released:2022-09-30)

参考文献数

29

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The efficacy of direct current (DC) cardioversion before catheter ablation (CA) for persistent atrial fibrillation (PerAF) patients remains controversial. We hypothesized that maintenance of sinus rhythm (SR) by pre-ablation DC cardioversion may predict the outcome of CA in patients with PerAF. A total of 383 PerAF patients with no or mild symptoms (EHRA I/II) who had undergone DC cardioversion before CA (301 males, 65 ± 10 years old, mean atrial fibrillation (AF) duration: 25 ± 47 months) were retrospectively enrolled. Whether or not SR was maintained at least 24 hour after DC cardioversion, patients were divided into two groups, namely, the DC-SR group and DC-AF group, and then all were followed until AF recurrence after CA. After DC cardioversion, 281 (73%) patients were categorized into the DC-SR group, and 102 (27%) were categorized into the DC-AF group. A total of 195 patients underwent CA at an average of 83 (54-145) days after DC cardioversion, including 161 (83%) in the DC-SR group and 34 (17%) in the DC-AF group. During follow-up (median: 15 [10-25] months), the number of patients who were free from AF was significantly higher in the DC-SR group compared with the DC-AF group (61.5% versus 38.3%, P < 0.0001). Multivariate analysis revealed that the DC-SR group (hazard ratio [HR]: 0.45, 95% confidence interval [CI]: 0.21-0.99, P = 0.047) and age at first AF diagnosis (HR: 0.95, 95% CI: 0.91-1.00, P = 0.039) were the independent predictors for being AF-free after CA. In conclusion, the 24-hour rhythm outcome of pre-ablation DC cardioversion and age at first AF diagnosis may predict the recurrence of AF after CA in patients with PerAF.

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

23

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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

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

28 221

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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.