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Background The wearable cardioverter-defibrillator (WCD) has been expected to play a role as an effective bridge therapy to implantable cardioverter-defibrillator (ICD) implantation in patients at high risk of ventricular tachyarrhythmias (VA). Although WCD has been available since April 2014 in Japan, its usefulness remains unclear. Methods and results During the early period after hospitalization, patients at high risk of VA after excluding some elderly patients were prescribed WCD. The consecutive 50 patients with WCD use (median age 56 years, 38 for secondary prevention) were studied. We analyzed clinical efficacy and safety of WCD, and examined its potential roles. Of the 50 patients, 38 used WCD only during hospitalization. During WCD use [median 16 (IQR 8–33) days], all patients wore WCD for 98% of a day regardless of in or out-of-hospital use. Sustained VA was detected in 4 patients (8%; for primary prevention in 1) with 7 episodes, and 6 of 7 episodes required shock therapy. Of the 6 shock therapies, 4 were for sustained ventricular tachycardia with the median rate of 236 beats/min (IQR 203–250), and the other 2 for ventricular fibrillation. Subsequently, only 27 patients (54%) of all underwent ICD implantation following the WCD use, because of reduced risk of VA after optimal pharmacological therapy or improvement in the left ventricular function. Conclusions The WCD use for the acute phase care of patients at high risk of VA can be safe and effective, and may be useful for evaluating indication of ICD implantation.

Objectives The aim of this study was to evaluate if residual thrombus burden after aspiration thrombectomy affects the outcomes of primary percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction (STEMI). Background Recent studies failed to show clinical benefit of aspiration thrombectomy in STEMI patients. This might be due to insufficient removal of thrombus at the culprit lesion. Methods A total of 109 STEMI patients who underwent aspiration thrombectomy followed by stenting within 24 h from symptom onset were included. Optical coherence tomography was performed after thrombectomy to measure residual thrombus burden. Patients were divided into tertiles based on the amount of residual thrombus and the outcomes were compared. Results Myocardial no reflow, defined as TIMI (Thrombolysis In Myocardial Infarction) flow grade of ≤2 and/or myocardial blush grade of ≤1 after stenting, was more observed frequently in patients in the highest tertile compared with those in the lowest tertile (44.4% vs. 16.7%; p = 0.001). Patients in the highest tertile also had greater myocardial damage measured by creatine kinase MB compared with those in the lowest tertile (p = 0.002). Conclusions STEMI patients with greater residual thrombus burden after aspiration thrombectomy had worse microvascular dysfunction and greater myocardial damage compared with those with smaller residual thrombus burden.

Diet-induced metabolic acidosis is associated with the impairment of bone metabolism and an increased risk of a number of chronic noncommunicable diseases, such as type 2 diabetes mellitus and hypertension. The serum bicarbonate level is an independent predictor of chronic kidney disease progression. We investigated whether proton accelerates aging by analyzing both coupling factor 6-overexpressing transgenic (TG) and high salt-fed mice which display sustained intracellular acidosis, due to enhanced proton import through ecto-F1 Fo complex and/or reduced proton export through Na+ -K+ ATPase inhibition. Both types of mice displayed shortened lifespan and early senescence-associated phenotypes such as signs of hair greying and alopecia, weight loss, and/or reduced organ mass. In chronic intracellular acidosis mice, autophagy was impaired by regression of Atg7, an increase in nuclear acetylated LC3 II, and acetylation of Atg7. The increase in histone 3 trimethylation at lysine 4 (H3K4me3) and H4K20me3 and the decrease in H3K9me3 and H3K27me3 were observed in the heart and kidney obtained from both TG and high salt-fed mice. The decrease in lamin A/C, emerin, and heterochromatin protein 1α without changes in barrier-to-autointegration factor and high-mobility group box 1 was confirmed in TG and high salt-fed mice. Suppression of nuclear histone deacetylase 3-emerin system is attributable to epigenetic regression of Atg7 and H4K5 acetylation. These findings will shed light on novel aging and impaired autophagy mechanism, and provide implications in a target for antiaging therapy.

Background— We reported that phospholipase C (PLC)-δ1 activity was enhanced 3-fold in patients with coronary spastic angina. We detected variant PLC-δ1 with replacement of arginine 257 by histidine (R257H) showing increased enzymatic activity. We tested the hypothesis that increased PLC-δ1 activity causes enhanced coronary vasomotility. Methods and Results— We generated transgenic (TG) mice with human R257H variant PLC-δ1 in vascular smooth muscle cells. PLC enzymatic activity in the coronary artery was increased by 2.57 and 1.89 times, respectively, in homozygous and heterozygous TG compared with wild-type (WT) mice. ST elevation after ergometrine occurred in 17 of 18 homozygous TG, 6 of 20 heterozygous TG, and 3 of 22 WT mice ( P P P =NS, heterozygous TG versus WT). ST elevation was associated with bradyarrhythmias in homozygous TG mice. Focal coronary artery narrowing was documented with the microvascular filling technique in 3 of 5 homozygous TG mice after ergometrine but not in any of 7 WT mice ( P P 2α was similar among homozygous TG, heterozygous TG, and WT mice. Cultured rat aortic smooth muscle cells transfected with variant PLC-δ1 showed a higher PLC activity than those with WT PLC-δ1 ( P 2+ response to acetylcholine in variant than in WT PLC-δ1 ( P Conclusions— Increased PLC-δ1 activity enhances coronary vasomotility such as that seen in patients with coronary spastic angina.

Matrix metalloproteinase (MMP)-9 plays an important role in cardiovascular events. However, the mechanisms underlying in vivo activation of MMP-9 are largely unknown. We investigated the secretion and activation of MMP-9 under a cell-to-cell interaction, and the effects of hypoxia and cytokine. Human umbilical vein endothelial cell (HUVEC) and THP-1 (human monocyte cell line) were cultured individually, or cocultured under normoxic and hypoxic conditions. In a coculture of HUVEC and THP-1, proMMP-9 secretion was increased twofold compared with individual culture of HUVEC and THP-1, whereas MMP-2 secretion was unchanged. The increase in proMMP-9 secretion was suppressed by antiadhesion molecule antibodies and mitogen-activated protein kinase inhibitors, PD98059 (MAPK/ERK kinase1 inhibitor) and SP600125 (Jun N-terminal kinase inhibitor). ProMMP-9 secretion was increased by tumor necrosis factor (TNF)-α at 50 ng/ml (P < 0.05) but was not activated under normoxic (20%) conditions. ProMMP-9 in coculture was activated under hypoxic (

Background Wearable cardioverter-defibrillators (WCD) have been available in Japan since April 2014, but their application is still limited. METHODS AND RESULTS: We report 9 patients with a WCD applied between April and September 2014. All patients were at high risk of life-threatening ventricular arrhythmias. During WCD use, 1 patient had sustained ventricular tachycardia and successful shock delivery; 6 (67%) subsequently underwent implantable cardioverter-defibrillator (ICD) therapy, while 2 had no requirement because of reduced risk, and 1 died of heart failure during WCD use. Conclusions WCD is useful during acute-phase care of high-risk patients, and may help to avoid unnecessary ICD implantation.

Objective Reactive oxygen species are involved in the pathogenesis of congestive heart failure. We recently showed that coupling factor 6, a component of adenosine trisphosphate (ATP) synthase, induces hypertension by intracellular acidosis, which is related to reactive oxygen species generation. We investigated the effect of high-salt diet on the cardiac performance and reactive oxygen species generation in coupling factor 6-overexpressing transgenic mice. Methods and results Baseline echocardiographic findings, reactive oxygen species generation, protein expression of sarcoplasmic/endoplasmic reticulum of Ca 2+ -ATPase 2 and phospholamban, and ATP content in the heart were similar between 7-week-old transgenic and wild-type mice. When the mice were fed with 8% salt diet for 20-24 weeks, fractional shortening of the left ventricle was decreased in transgenic mice compared with wild-type mice and was recovered by intraperitoneal administration of anticoupling factor 6 antibody. Nicotinamide adenine dinucleotide phosphate oxidase activity in the heart was increased in transgenic mice after the high-salt diet concomitantly with c-Src activation. The level of 8-iso-prostaglandin F 2α was increased in transgenic heart compared with wild-type heart. The protein expression of sarcoplasmic/endoplasmic reticulum of Ca 2+ -ATPase 2 was decreased and that of phospholamban was increased in transgenic heart. In cDNA microarray analysis, the genes related to ATP synthesis and glycolysis were decreased in transgenic heart, concomitantly with the decrease in ATP content and the increase in β-myosin heavy chain. Conclusion These suggest that coupling factor 6 induces the development of systolic dysfunction and upregulation of nicotinamide adenine dinucleotide phosphate oxidase in the heart under the high-salt diet.

Background: Although unmarried has been associated with an increased risk of acute coronary syndrome, little is known about the relationship between marital status and long-term mortality after acute myocardial infarction (AMI). Methods and Results: To elucidate the clinical characteristics and outcomes of AMI patients who have never married, the consecutive 364 male AMI patients (mean age; 63±13 years) admitted to our hospital were studied. Mean follow-up period was 1.7 years. The patients were divided into 2 groups by their marital status: those who had married at least one time (Married Group (MG), n=328) and those who had never married (Unmarried Group (UG), n=36 (9.9%)). UG patients were younger (54±11 vs 65±12 years, p50 years (272 patients in MG and 19 in UG), all-cause mortality tended to be higher in UG than in MG (38% vs 15%, p=0.098 by Log-rank test). After adjustment for age, Killip IV and LVEF at the acute phase, unmarried status was independently associated with all-cause long-term mortality after AMI (hazard ratio (HR); 3.84, 95% confidence interval (CI); 1.22-10.2, p=0.024). Conclusions: Unmarried status is independently associated with significantly increased all-cause long-term mortality in the male AMI patients with the ages >50 years.

BACKGROUND Regular exercise improves systolic cardiac dysfunction through Akt cascade-mediated physiological hypertrophy in congestive heart failure. Tissue acidosis impairs Akt cascade, and coupling factor 6 induces tissue acidosis via activation of ecto-F(1)F(o) complex. We tested the hypothesis that coupling factor 6 attenuates physiological cardiac hypertrophy induced by exercise and its benefit in mice. METHODS AND RESULTS Adult wild-type mice (n = 20) and coupling factor 6-overexpressing transgenic mice (n = 20) were divided into two groups with or without 4-week exercise consisting of 90-min swimming twice daily. Left ventricular posterior wall and interventricular septum thicknesses were increased by 0.12 ± 0.1 and 0.16 ± 0.1 mm, respectively, after 4-week swimming in wild-type mice (both P

In male coupling factor 6 (CF6)-overexpressing transgenic (TG) mice, a high-salt diet induces hypertension and cardiac systolic dysfunction with excessive reactive oxygen species generation. However, the role of gender in CF6-mediated pathophysiology is unknown. We investigated the effects of ovariectomy and estrogen replacement on hypertension, cardiac dysfunction and Rac1 activity, which activates radical generation and the mineralocorticoid receptor, in female TG mice. Fifteen-week-old male and female TG and wild-type (WT) mice were fed a normal- or high-salt diet for 60 weeks. Systolic and diastolic blood pressures were higher in the TG mice fed a high-salt diet than in those fed a normal-salt diet at 20-60 weeks in males but only at 60 weeks in females. The blood pressure elevation under high-salt diet conditions was concomitant with a decrease in left ventricular fractional shortening. In the WT mice, neither blood pressure nor cardiac systolic function was influenced by a high-salt diet. In the female TG mice, bilateral ovariectomy induced hypertension with cardiac systolic dysfunction 8 weeks after the initiation of a high-salt diet. The ratios of Rac1 bound to guanosine triphosphate (Rac1-GTP) to total Rac1 in the heart and kidneys were increased in the ovariectomized TG mice, and estrogen replacement abolished the CF6-mediated pathophysiology induced under the high-salt diet conditions. The overexpression of CF6 induced salt-sensitive hypertension, complicated by systolic cardiac dysfunction, but its onset was delayed in females. Estrogen has an important role in the regulation of CF6-mediated pathophysiology, presumably via the downregulation of Rac1.