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Background: The mineralocorticoid receptor antagonist eplerenone improved clinical outcomes among patients with heart failure with reduced ejection faction (HFrEF) in the EMPHASIS-HF (Eplerenone in Mild Patients Hospitalization And SurvIval Study in Heart Failure) study. However, similar efficacy and safety have not been established in Japanese patients. We evaluated the efficacy and safety of eplerenone in patients with HFrEF in a multicenter, randomized, double-blind placebo-controlled outcome study (ClinicalTrials.gov Identifier: NCT01115855). The aim of the study was to evaluate efficacy predefined as consistency of the primary endpoint with that of EMPHASIS-HF at a point estimate of <1 for the hazard ratio.Methods and Results:HFrEF patients with NYHA functional class II-IV and an EF ≤35% received eplerenone (n=111) or placebo (n=110) on top of standard therapy for at least 12 months. The primary endpoint was a composite of death from cardiovascular causes or hospitalization for HF. The primary endpoint occurred in 29.7% of patients in the eplerenone group vs. 32.7% in the placebo group [hazard ratio=0.85 (95% CI: 0.53-1.36)]. Hospitalization for any cause and changes in plasma BNP and LVEF were favorable with eplerenone. A total of 17 patients (15.3%) in the eplerenone group and 10 patients (9.1%) in the placebo group died. Adverse events, including hyperkalemia, were similar between the groups., Conclusions: Eplerenone was well-tolerated in Japanese patients with HFrEF and showed results consistent with those reported in the EMPHASIS-HF study.

Bisoprolol fumarate (bisoprolol) is a β-blocker widely used to treat chronic heart failure (CHF). However, few studies have compared its efficacy and safety with those of the widely used β-blocker carvedilol in Japanese patients with CHF. We designed a confirmatory trial of bisoprolol using carvedilol as a control drug; however, the trial was discontinued after an off-label use of bisoprolol was approved during the study. Bisoprolol and carvedilol were administered for 32 weeks in 31 and 28 patients, respectively. The mean maintenance doses of bisoprolol and carvedilol were 3.3 and 13.6 mg/day, respectively, and the mean durations of treatment were 188.2 and 172.9 days, respectively. Heart-rate changes were similar in both groups. The mean changes from baseline to Week 32 in left ventricular (LV) ejection fraction (EF) (bisoprolol vs carvedilol groups; 11.7 % ± 8.6 % vs 10.1 % ± 10.5 %), LV end-diastolic volume (-37.5 ± 48.7 vs -24.7 ± 29.4 ml), and LV end-systolic volume (-41.9 ± 43.0 vs -29.3 ± 25.9 ml) revealed a decrease in LV volume and an increase in LVEF in both groups. The cumulative event-free rate for a composite of cardiovascular death or admissions to hospital for worsening of CHF was 92.4 % and 94.7 % in the bisoprolol and carvedilol groups, respectively. Overall, 90.3 % and 85.7 % of patients were titrated up to the maintenance doses of bisoprolol and carvedilol, respectively. Bisoprolol, at half the dose used in other countries, is well tolerated and is as effective as carvedilol for treating Japanese patients with mild to moderate CHF.

Objective: Recently, we reported that low-dose landiolol (1.5 µg·kg(-1)·min(-1)), an ultra-short-acting β-blocker, safely decreased the heart rate (HR) in patients with acute decompensated heart failure (ADHF) and sinus tachycardia, thereby improving cardiac function. We investigated whether low-dose landiolol effectively decreased the HR in ADHF patients with rapid atrial fibrillation (AF)., Methods: We enrolled 23 ADHF patients with rapid AF (HR ≥120 beats·min(-1) and New York Heart Association class III-IV) and systolic heart failure (SHF: n = 12) or diastolic heart failure (DHF: n = 11) who received conventional therapy with diuretics, vasodilators, and/or low-dose inotropes. They were administered continuous intravenous infusion of low-dose landiolol (1.0-2.0 µg·kg(-1)·min(-1)), and their electrocardiograms and blood pressures were monitored for 24 h thereafter., Results: Two hours after starting landiolol, the HR was reduced significantly (22%), without a reduction in blood pressure, and remained constant thereafter. The HR reduction 2 h after landiolol administration was significantly greater in the DHF group than in the SHF group. No incidence of hypotension was recorded., Conclusions: Digitalis or amiodarone is currently recommended for HR control in ADHF patients with rapid AF. Our results showed that continuous infusion of low-dose landiolol may also be useful as first-line therapy in these patients., (© 2013 S. Karger AG, Basel.)

Background: In chronic heart failure (CHF), it remains unclear whether the minimal dose of beta-blockade is related to survival benefits and which parameter predicts morbidity and mortality. We sought to determine the minimal dose related to survival benefits by comparing the efficacy and safety of three doses of carvedilol and the best predictive parameter for effective outcomes in Japanese patients with CHF., Methods: In this prospective, randomized, stratified trial, 364 patients with mild to moderate CHF were assigned to a daily carvedilol dose of 2.5, 5, or 20mg, plus optimal standard therapy., Findings: During the mean 3-year follow-up, resting heart rate (HR) and BNP were significantly reduced with dose-response relations in the early period but without dose-response relations in the late period. The LVEF and the LVDd were increased and decreased, respectively, without a dose-response relation. No significant difference was seen in the composite primary endpoint of all-cause mortality and hospitalization for cardiovascular diseases and heart failure. Multivariate analysis indicated early decreases in HR and BNP predicted long-term outcomes. However, adverse events increased dose-dependently. Among 237 polymorphisms in 87 heart failure-related genes, the osteopontin G-156 del genotype was associated with an event-free survival rate (Wilcoxon test, P=0.030)., Conclusions: A low carvedilol dose is effective if the HR and/or plasma BNP has been reduced. Carvedilol therapy should be guided by reductions in HR and/or BNP, especially by initial HR reduction, but not only by its dose. OPN might be a surrogate genetic marker for long-term event-free survival., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Background: Chronic heart failure (CHF) is an increasingly common cardiovascular disease despite recent advances in its diagnosis and management., Methods and Results: A multicenter, open-label study was designed to assess the efficacy and safety of 60-week treatment with candesartan in Japanese patients with mild to moderate CHF. Primary efficacy endpoints were changes from baseline in plasma brain natriuretic peptide (BNP), left ventricular ejection fraction (LVEF), end-diastolic dimension, and New York Heart Association (NYHA) functional class. Two hundred and eighty-nine eligible patients were divided into 2 groups based on the daily dose at the end of treatment: high-dose (HD, 8mg, N=170) and low-dose (LD, 2 or 4mg, N=119). Neither plasma BNP levels nor LVEF changed from the baseline to the end of treatment in the LD group, whereas BNP significantly improved from 61.6 to 50.1pg/mL (p=0.0005) and LVEF from 57.2 to 60.1% (p=0.0005) in the HD group. The changes in NYHA functional class were comparable between groups: 21.2% improved and 76.3% unchanged in the LD group and 20.6% improved and 79.4% unchanged in the HD group. No safety concerns were observed in either group., Conclusions: HD candesartan was more effective in improving plasma BNP levels and cardiac function than LD in Japanese CHF patients. Both LD and HD candesartan were well tolerated in CHF patients., (Copyright © 2013 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.)

Background: We have previously demonstrated that the prevalence of metabolic syndrome in chronic heart failure (CHF) is more than double compared with the general population in Japan. However, the impact of physical activity on cardiovascular events in CHF patients remains to be fully elucidated., Methods and Results: We performed a prospective, nationwide large-scale multicenter study of 9,178 patients with stage A/B/C/D CHF in Japan. We obtained the baseline physical activity data for 7,292 and yearly changes in physical activity data during a 3-year follow-up period for 4,353 patients. We divided the patients into high- and low-exercise groups by using the median value of physical activity in the stage A/B and C/D groups. In both groups, patients who exercised more were characterized by younger age and less advanced stage of CHF. Importantly, the baseline physical activity levels were significantly associated with all-cause death, heart failure (HF) hospitalization and other cardiovascular events (except acute myocardial infarction, stroke, HF hospitalization). Furthermore, the yearly change in physical activity level was also significantly associated with HF hospitalization and other cardiovascular events in both groups., Conclusions: The baseline level of physical activity and its yearly changes are significantly associated with all-cause death and major cardiovascular events in both stage A/B and C/D patients, suggesting that physical activity could be an important therapeutic target to improve the long-term prognosis of CHF patients.

Aims: The channel function of the cardiac ryanodine receptor (RyR2) is modulated by calmodulin (CaM). However, the involvement of CaM in aberrant Ca(2+) release in diseased hearts remains unclear. Here, we investigated the pathogenic role of defective CaM binding to the RyR2 in the channel dysfunction associated with heart failure., Methods and Results: The involvement of CaM in aberrant Ca(2+) release was assessed in normal and pacing-induced failing canine hearts. The apparent affinity of CaM for RyR2 was considerably lower in failing sarcoplasmic reticulum (SR) compared with normal SR. Thus, the amount of CaM bound to RyR2 was markedly decreased in failing myocytes. Expression of the CaM isoform Gly-Ser-His-CaM (GSH-CaM), which has much higher binding affinity than wild-type CaM for RyR1, restored normal CaM binding to RyR2 in both SR and myocytes of failing hearts. The Ca(2+) spark frequency (SpF) was markedly higher and the SR Ca(2+) content was lower in failing myocytes compared with normal myocytes. The incorporation of GSH-CaM into the failing myocytes corrected the aberrant SpF and SR Ca(2+) content to normal levels., Conclusion: Reduced CaM binding to RyR2 seems to play a critical role in the pathogenesis of aberrant Ca(2+) release in failing hearts. Correction of the reduced CaM binding to RyR2 stabilizes the RyR2 channel function and thereby restores normal Ca(2+) handling and contractile function to failing hearts.

Background: The purpose of this study was to determine whether a low-dose β-blocker, in combination with milrinone, improves cardiac function in acute decompensated heart failure (ADHF) with tachycardia., Methods and Results: Twenty ADHF patients (New York Heart Association classification III, n=1, and IV, n=19; heart rate [HR], 107±12 beats/min; left ventricular ejection fraction, 24±7%; cardiac index [CI], 2.2±0.6 L·min(-1)·m(-2); pulmonary capillary wedge pressure [PCWP], 26±8 mmHg) were enrolled in this study. The patients first underwent conventional therapy with milrinone, vasodilators and diuretics; landiolol (1.5-6.0 µg·kg(-1)·min(-1); i.v.), which is an ultra-short-acting β(1)-selective blocker, was then added to the treatment regimen to study its effect on hemodynamics. Low-dose landiolol (1.5 µg·kg(-1)·min(-1)) significantly reduced HR by 11% without changing blood pressure (BP) and CI, whereas higher doses (≥3.0 µg·kg(-1)·min(-1)) tended to decrease BP and CI while increasing PCWP and systemic vascular resistance. After treatment with landiolol (1.5 µg·kg(-1)·min(-1)), hemodynamic parameters such as PCWP, stroke volume index, SvO(2), rate pressure product, filling time/RR, E/e', and Tei index were significantly improved., Conclusions: A low-dose β-blocker in combination with milrinone improved cardiac function in ADHF patients with tachycardia; therefore, it may be considered as an adjunct therapy for use when standard therapy with milrinone is not effective at slowing HR.

Background: The targeting of Ca(2+) cycling has emerged as a potential therapy for the treatment of severe heart failure. These approaches include gene therapy directed at overexpressing sarcoplasmic reticulum (SR) Ca(2+) ATPase, or ablation of phospholamban (PLN) and associated protein phosphatase 1 (PP1) protein complexes. We previously reported that PP1β, one of the PP1 catalytic subunits, predominantly suppresses Ca(2+) uptake in the SR among the three PP1 isoforms, thereby contributing to Ca(2+) downregulation in failing hearts. In the present study, we investigated whether heart-failure-inducible PP1β-inhibition by adeno-associated viral-9 (AAV9) vector mediated gene therapy is beneficial for preventing disease progression in genetic cardiomyopathic mice., Methods: We created an adeno-associated virus 9 (AAV9) vector encoding PP1β short-hairpin RNA (shRNA) or negative control (NC) shRNA. A heart failure inducible gene expression system was employed using the B-type natriuretic protein (BNP) promoter conjugated to emerald-green fluorescence protein (EmGFP) and the shRNA sequence. AAV9 vectors (AAV9-BNP-EmGFP-PP1βshRNA and AAV9-BNP-EmGFP-NCshRNA) were injected into the tail vein (2×10(11) GC/mouse) of muscle LIM protein deficient mice (MLPKO), followed by serial analysis of echocardiography, hemodynamic measurement, biochemical and histological analysis at 3 months., Results: In the MLPKO mice, BNP promoter activity was shown to be increased by detecting both EmGFP expression and the induced reduction of PP1β by 25% in the myocardium. Inducible PP1βshRNA delivery preferentially ameliorated left ventricular diastolic function and mitigated adverse ventricular remodeling. PLN phosphorylation was significantly augmented in the AAV9-BNP-EmGFP-PP1βshRNA injected hearts compared with the AAV9-BNP-EmGFP-NCshRNA group. Furthermore, BNP production was reduced, and cardiac interstitial fibrosis was abrogated at 3 months., Conclusion: Heart failure-inducible molecular targeting of PP1β has potential as a novel therapeutic strategy for heart failure.

Aims: The intercalated disc (ID) contains two complexes, the adhesion junction (AJ) and the gap junction (GJ). We studied ID remodelling and its potential role in arrhythmogenesis and investigated the effects of olmesartan on ID remodelling during development of heart failure (HF) in UM-X7.1 cardiomyopathic hamsters., Methods and Results: The UM-X7.1 hamsters showed left ventricular (LV) hypertrophy by the age of 10-15 weeks and a moderate impairment in LV contractility at 20 weeks. At age 10-15 weeks, 10-20% of the hamsters died suddenly without HF, and ventricular tachycardia (VT)/ventricular fibrillation (VF) was induced in ∼30% of hamsters. Electron microscopy showed that density linking cell-to-cell adhesion was irregular and unclearly defined, and filamentous structures attached to electron-dense components were arranged in disorder. Western blotting showed that the total cellular expression level of β-catenin was decreased, and expression of nuclear β-catenin, which functions as a T-cell factor/lymphocyte enhancer binding factor transcriptional activator, was also remarkably decreased. At age 20 weeks, LV connexin43 expression showed a remarkable decrease, and the VT/VF induction rate was ∼90%. In UM-X7.1 hamsters, olmesartan improved abnormal ID ultrastructural changes, attenuated the decrease of total cellular and nuclear β-catenin expression, decreased VT/VF induction, and improved survival rate., Conclusion: These results suggest that changes in AJ protein precede connexin43 GJ alterations, and ID remodelling might contribute to arrhythmogenesis during the development of HF. Angiotensin receptor blockade might be a new therapy for lethal ventricular arrhythmia by modulating both AJ and GJ remodelling.

Background: Spironolactone was shown to reduce mortality in patients with heart failure (HF). However, the effect of spironolactone on the incidence of atrial fibrillation remains unknown. Therefore, we examined the effects of spironolactone on atrial conduction and remodeling in patients with HF., Methods and Results: A total of 21 patients with HF were divided into either spironolactone group (n=11) or control group (n=10). The patients were followed up for 12 months. Blood examination, echocardiogram, and signal-averaged electrocardiogram were performed at study enrollment and after 3 and 12 months of treatment. In the spironolactone group, atrial natriuretic peptide tended to reduce, left atrium dimension was significantly smaller, the ratio of E wave to A wave tended to improve, and P-duration was significantly shortened., Conclusions: Spironolactone improves atrial conduction and remodeling in patients with HF., (Copyright © 2011 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.)

Background: Metabolic syndrome (MetS) is a pathological condition with a clustering of metabolic components and is a well-known risk and prognostic factor for ischemic heart disease (IHD). However, the prevalence and clinical significance of MetS remain to be fully elucidated in chronic heart failure (CHF), an important clinical syndrome caused by various cardiac abnormalities., Methods and Results: The present nationwide, large-scale clinical study enrolled 3,603 patients with stage C/D CHF from 6 institutes in Japan. First, the prevalence of MetS in CHF patients was demonstrated to be 45% in males and 19% in females, which is more than double compared with the general population in Japan. The CHF patients with MetS were characterized by younger age, higher prevalence of current smoking and drinking, IHD, and hypertensive heart disease, whereas the prevalence of HF with preserved ejection fraction and MetS was higher in elderly female patients. Next, the contribution of the metabolic components (waist circumference, hypertension, glucose intolerance/diabetes mellitus and dyslipidemia) was found to be comparable between the ischemic and the non-ischemic CHF patients., Conclusions: The prevalence of MetS in CHF patients is more than double compared with the general population in Japan and suggest that the metabolic components may have a substantial effect on the development of both ischemic and non-ischemic CHF.

Background: The washout rate (WR) of (123)I-metaiodobenzylguanidine (MIBG) is now widely used for assessing the severity of heart failure. Although the WR of MIBG is usually measured at rest, the assessment of WR of MIBG during exercise might have a different clinical relevance. In this study, we measured the WR rate of MIBG during low-grade exercise and studied the clinical importance of this novel index., Methods: Twenty-four patients with dilated cardiomyopathy (DCM) were enrolled in this study. Planar images were obtained 20 minutes after MIBG injection (first image) and after 270 minutes (second image); the third image was obtained after 15 minutes of low-grade (10 W) bicycle ergometer exercise (300 minutes after MIBG injection). The decay of the specific counts was calculated from the first two images. The estimated third counts were calculated from the resting decay and were compared with the actual third counts., Results: In the receiver operating characteristic (ROC) curve analysis, we set a 10% decrease from the estimated counts as a cut-off value for severe heart failure (New York Heart Association [NYHA] Class IIm or worse). In 15 patients, the actual third count value was within 10% of the estimated count (N-group). In nine patients, the WR during exercise was high, and the actual third count values showed more than a 10% decrease from the estimated count value (H-group). In the H-group, 78% of the patients were in NYHA class IIm or III. In contrast, in the N-group, no patient had NYHA class III, and only 20% of the patients were in class IIm. The brain natriuretic peptide (BNP) level was significantly higher in the H-group than in the N-group (525 ± 263 pg/mL vs 176 ± 144 pg/mL; P < .01). No significant differences were observed in heart/mediastinal (H/M) activity ratio, the regular WR, and left ventricular ejection fraction values between the two groups., Conclusions: The WR of MIBG during exercise may be an independent prediction variable, with a clinical relevance different from that of the WR at rest. This measurement could be used as a new index for assessing the severity of heart failure.

Aims: Calmodulin (CaM) is well known to modulate the channel function of the cardiac ryanodine receptor (RyR2). However, the possible role of CaM on the aberrant Ca(2+) release in diseased hearts remains unclear. In this study, we investigated the state of RyR2-bound CaM and channel dysfunctions in pacing-induced failing hearts., Methods and Results: The characteristics of CaM binding to RyR2 and the role of CaM on the aberrant Ca(2+) release were assessed in normal and failing canine hearts. The affinity of CaM binding to RyR2 was lower in failing sarcoplasmic reticulum (SR) than in normal SR. Addition of FK506, which dissociates FKBP12.6 from RyR2, to normal SR reduced the CaM-binding affinity. Dantrolene restored a normal level of the CaM-binding affinity in either FK506-treated (normal) SR or failing SR, suggesting that the defective inter-domain interaction between the N-terminal domain and the central domain of RyR2 (the therapeutic target of dantrolene) is involved in the reduction of the CaM-binding affinity in failing hearts. In saponin-permeabilized cardiomyocytes, the frequency of spontaneous Ca(2+) sparks was much more increased in failing cardiomyocytes than in normal cardiomyocytes, whereas the addition of a high concentration of CaM attenuated the aberrant increase of Ca(2+) sparks., Conclusion: The defective inter-domain interaction between N-terminal and central domains within RyR2 reduces the binding affinity of CaM to RyR2, thereby causing the spontaneous Ca(2+) release events in failing hearts. Correction of the defective CaM binding may be a new strategy to protect against the aberrant Ca(2+) release in heart failure.

Background: Intermittent pneumatic compression (IPC) has been used to prevent deep venous thrombosis (DVT), but the effects of IPC on the hemodynamics of popliteal and soleal veins, especially in patients with congestive heart failure (CHF) have not been evaluated. The aim of this study was to evaluate the effects of IPC on the flow velocity of deep veins in the lower extremities and to compare the efficacy of two different types of IPC in deep venous flow enhancement in patients with CHF., Methods: Flow velocities of popliteal and soleal veins were recorded in 19 patients with CHF and in 19 control subjects using a high-resolution linear probe. Peak and mean flow velocities were measured (1) at rest, (2) with sequential foot and calf IPC (SFC-IPC) which consists of an electrically driven air compressor and four air chambers, and (3) with impulse foot IPC (IF-IPC) which consists of a pneumatic impulse generator operated at an applied pressure of 130 mmHg., Results: In the resting condition, popliteal venous flow velocity in the CHF group was attenuated (12.8+/-4.7 cm/s vs. 21.1+/-13.5 cm/s; p<0.05). Both SFC-IPC and IF-IPC increased venous velocity, but the increase with IF-IPC in CHF patients was lower than that in control subjects. In the soleal veins, after applying SFC-IPC, the peak and mean velocity in CHF increased to the same extent as in the control group. IF-IPC increased soleal venous velocity in control subjects, but there was no increase in CHF patients., Conclusion: Two-dimensional Doppler scanning revealed a significant increase in the mean and peak velocities in the soleal and popliteal veins with SFC-IPC but not with IF-IPC in patients with CHF. These results indicate that SFC-IPC could have favorable effects in preventing DVT in patients with CHF., (Copyright 2010 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.)

Background: Previously, we reported the benefit of 12 weeks of home oxygen therapy (HOT) in patients with central sleep apnea (CSA) and heart failure (HF). In the present study, we attempted to confirm the sustained efficacy of HOT in the long term treatment., Methods and Results: In the present study, 51 patients with CSA and HF (New York Heart Association (NYHA) functional classes II-III) were assigned to receive either nocturnal oxygen (HOT group n=26) or usual breathing (control group n=25) for 52 weeks. In the HOT group, greater reduction in apnea and hypopnea and greater increase in nocturnal oxygen saturation were observed. These changes were associated with greater improvement in the Specific Activity Scale (0.82 +/-1.17 vs -0.11 +/-0.73 Mets, P=0.009) in NYHA functional class (P=0.007) and in ejection fraction (5.45 +/-11.94 vs 1.28 +/-9.77%). There were no significant differences in the cardiac event rates; however, the later divergence favored the HOT group., Conclusions: The 52-week HOT was well tolerated and the benefit observed in the 12-week trial was sustained over a prolonged period of time. HOT was considered to be a valuable non-pharmacological therapeutic addition for HF patients with CSA.

Objectives: We sought to investigate the effect of dantrolene, a drug generally used to treat malignant hyperthermia, on the Ca2+ release and cardiomyocyte function in failing hearts., Background: The N-terminal (N: 1-600) and central (C: 2000-2500) domains of the ryanodine receptor (RyR) harbor many mutations associated with malignant hyperthermia in skeletal muscle RyR (RyR1) and polymorphic ventricular tachycardia in cardiac RyR (RyR2). There is strong evidence that interdomain interaction between these regions plays an important role in the mechanism of channel regulation., Methods: Sarcoplasmic reticulum vesicles and cardiomyocytes were isolated from the left ventricular muscles of dogs (normal or rapid ventricular pacing for 4 weeks), for Ca2+ leak, transient, and spark assays. To assess the zipped or unzipped state of the interacting domains, the RyR was labeled fluorescently with methylcoumarin acetate in a site-directed manner. We used a quartz-crystal microbalance technique to identify the dantrolene binding site within the RyR2., Results: Dantrolene specifically bound to domain 601-620 in RyR2. In the sarcoplasmic reticulum isolated from pacing-induced failing dog hearts, the defective interdomain interaction (domain unzipping) had already occurred, causing spontaneous Ca2+ leak. Dantrolene suppressed both domain unzipping and the Ca2+ leak, demonstrating identical drug concentration-dependence (IC50 = 0.3 micromol/l). In failing cardiomyocytes, both diastolic Ca2+ sparks and delayed afterdepolarization were observed frequently, but 1 micromol/l dantrolene inhibited both events., Conclusions: Dantrolene corrects defective interdomain interactions within RyR2 in failing hearts, inhibits spontaneous Ca2+ leak, and in turn improves cardiomyocyte function in failing hearts. Thus, dantrolene may have a potential to treat heart failure, specifically targeting the RyR2.

Aims: A domain peptide (DP) matching the Gly(2460)-Pro(2495) region of the cardiac type-2 ryanodine receptor (RyR2), DPc10, is known to mimic channel dysfunction associated with catecholaminergic polymorphic ventricular tachycardia (CPVT), owing to its interference in a normal interaction of the N-terminal (1-600) and central (2000-2500) domains (viz. domain unzipping). Using DPc10 and two other DPs harboring different mutation sites, we investigated the underlying mechanism of abnormal Ca(2+) cycling in failing hearts., Methods and Results: Sarcoplasmic reticulum (SR) vesicles and cardiomyocytes were isolated from dog left ventricular muscles for Ca(2+) leak and spark assays. The RyR2 moiety of the SR was fluorescently labelled with methylcoumarin acetate (MCA) using DPs corresponding to the 163-195 and 4090-4123 regions of RyR2 (DP163-195 and DP4090-4123, respectively) as site-directed carriers. Both DPs mediated a specific MCA fluorescence labelling of RyR2. Addition of either DP to the MCA-labelled SR induced domain unzipping, as evidenced by an increased accessibility of the bound MCA to a large-size fluorescence quencher. Both SR Ca(2+) leak and Ca(2+) spark frequency (SpF) were markedly increased in failing cardiomyocytes. Upon introduction of DP163-195 or DP4090-4123 into normal SR or cardiomyocytes, both Ca(2+) leak and SpF increased to the levels comparable with those of failing myocytes. K201 (JTV519) suppressed all of the effects induced by DP163-195 (domain unzipping and increased Ca(2+) leak and SpF) or those in failing cardiomyocytes, but did not suppress the effects induced by DP4090-4123., Conclusion: Defective inter-domain interaction between N-terminal and central domains induces diastolic Ca(2+) leak, leading to heart failure and lethal arrhythmia. Mutation at the C-terminal region seen in CPVT does not seem to communicate with the aforementioned N-terminal and central inter-domain interaction, although spontaneous Ca(2+) leak is similarly induced.

Abnormal Ca²(+) cycling is important in various cardiac diseases. Evidence has accumulated that dysregulation of Ca²(+) release from the ryanodine receptor (RyR2) plays a significant role in cardiac dysfunction. Spontaneous Ca²(+) release through RyR2 during diastole decreases sarcoplasmic reticulum (SR) Ca²(+) content, and also induces delayed after depolarization (DAD) as a substrate for lethal arrhythmia. Several disease-linked mutations in the RyR have been reported in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT) or arrythmogenic right ventricular cardiomyopathy type 2 (ARVC2). The unique distribution of these mutation sites has produced the concept that the interaction among the putative regulatory domains within the RyR may play a key role in regulating the channel opening, and that there seems to be a common abnormality in the channel disorder between heart failure and CPVT/ARVC2. We review here the considerable body of evidence regarding defective channel gating of RyR2 in the pathogenesis of heart failure and lethal arrhythmia.

Background: We conducted a prospective multicenter case-control study to confirm the clinical efficacy and safety of Waon therapy on chronic heart failure (CHF)., Methods: Patients (n=188) with CHF were treated with standard therapy for at least 1 week, and then were randomized to Waon therapy (n=112) or a control group (n=76). All patients continued conventional treatment for an additional 2 weeks. The Waon therapy group was treated daily with a far infrared-ray dry sauna at 60 degrees C for 15 min and then kept on bed rest with a blanket for 30 min for 2 weeks. Chest radiography, echocardiography, and plasma levels of brain natriuretic peptide (BNP) were measured before and 2 weeks after treatment., Results: NYHA functional class significantly decreased after 2 weeks of treatment in both groups. Chest radiography also showed a significant decrease of the cardiothoracic ratio in both groups (Waon therapy: 57.2+/-8.0% to 55.2+/-8.0%, p<0.0001; control: 57.0+/-7.7% to 56.0+/-7.1%, p<0.05). Echocardiography demonstrated that left ventricular diastolic dimension (LVDd), left atrial dimension (LAD), and ejection fraction (EF) significantly improved in the Waon therapy group (LVDd: 60.6+/-7.6 to 59.1+/-8.4 mm, p<0.0001; LAD: 45.4+/-9.3 mm to 44.1+/-9.4 mm, p<0.05; EF: 31.6+/-10.4% to 34.6+/-10.6%, p<0.0001), but not in the control group (LVDd: 58.4+/-10.3 mm to 57.9+/-10.4 mm; LAD: 46.3+/-9.7 mm to 46.2+/-10.1 mm; EF: 36.6+/-14.1% to 37.3+/-14.0%). The plasma concentration of BNP significantly decreased with Waon therapy, but not in the control group (Waon: 542+/-508 pg/ml to 394+/-410 pg/ml, p<0.001; control: 440+/-377 pg/ml to 358+/-382 pg/ml)., Conclusion: Waon therapy is safe, improves clinical symptoms and cardiac function, and decreases cardiac size in CHF patients. Waon therapy is an innovative and promising therapy for patients with CHF.

Heart failure is known to predispose to life-threatening ventricular tachyarrhythmias even before compromising the systemic circulation, but the underlying mechanism is not well understood. The aim of this study was to clarify the connexin43 (Cx43) gap junction remodeling and its potential role in the pathogenesis of arrhythmias during the development of heart failure. We investigated stage-dependent changes in Cx43 expression in UM-X7.1 cardiomyopathic hamster hearts and associated alterations in the electrophysiological properties using a high-resolution optical mapping system. UM-X7.1 hamsters developed left ventricular (LV) hypertrophy by ages 6 approximately 10 wk and showed a moderate reduction in LV contractility at age 20 wk. Appreciable interstitial fibrosis was recognized at these stages. LV mRNA and protein levels of Cx43 in UM-X7.1 were unaffected at age 10 wk but significantly reduced at 20 wk. The expression level of Ser255-phosphorylated Cx43 in UM-X7.1 at age 20 wk was significantly greater than that in control golden hamsters at the same age. In UM-X7.1 at age 10 wk, almost normal LV conduction was preserved, whereas the dispersion of action potential duration was significantly increased. UM-X7.1 at age 20 wk showed significant reduction of cardiac space constant, significant decrease in conduction velocity, marked distortion of activation fronts, and pronounced increase in action potential duration dispersion. Programmed stimulation resulted in sustained ventricular tachycardia or fibrillation in UM-X7.1. LV activation during polymorphic ventricular tachycardia was characterized by multiple phase singularities or wavebreaks. During the development of heart failure in the cardiomyopathic hamster, alterations of Cx43 expression and phosphorylation in concert with interstitial fibrosis may create serious arrhythmogenic substrate through an inhibition of cell-to-cell coupling.

Structural and functional alterations in the Ca(2+) regulatory proteins present in the sarcoplasmic reticulum (SR) have recently been shown to play a crucial role in the pathogenesis of heart failure (HF), and lethal arrhythmia as well. Chronic activation of the sympathetic nervous system induces abnormalities in both the function and structure of these proteins. For instance, the diastolic Ca(2+) leak through the SR Ca(2+) release channel (ryanodine receptor) reduces the SR Ca(2+) content, inducing contractile dysfunction. Moreover, the Ca(2+) leak provides a substrate for delayed after depolarization that leads to lethal arrhythmia. There is a considerable body of evidence regarding the role of Ca(2+) cycling abnormality in HF.

Objectives: We examined whether the inhibition of apoptosis signal-regulating kinase 1 (ASK1) would attenuate the progression of heart failure in TO-2 hamsters with hereditary dilated cardiomyopathy., Background: Heart failure remains the leading cause of mortality and requires novel therapies targeting the biologically relevant processes within cardiomyocytes that lead to cell death. Apoptosis signal-regulating kinase 1 is a key signaling molecule for cardiomyocyte death., Methods: We generated recombinant adeno-associated virus (rAAV) expressing an N-terminal truncated form of the dominant-negative mutant of ASK1 (ASKdeltaN(KR)). TO-2 hamsters were subjected to an in vivo rAAV transcoronary transfer., Results: ASKdeltaN(KR) retained its dominant-negative activity in vitro. The rAAV expressing ASKdeltaN(KR) treatment inhibited ASK1 activation in the hamster hearts and suppressed progression of ventricular remodeling such as chamber dilation, impairment of contractile and relaxation functions, and fibrosis. Inhibition of ASK1 reduced the number of apoptotic cells and selectively attenuated c-Jun NH2-terminal kinase activation. Although the deficiency of delta-sarcoglycan, a genetic defect in the hamster, leads to the degradation of dystrophin, the treatment significantly protected hearts from this degradation, probably by inhibiting calpain activation., Conclusions: Apoptosis signal-regulating kinase 1 is involved in the pathogenesis of heart failure progression, mediated through c-Jun NH2-terminal kinase-mediated apoptosis and calpain-dependent dystrophin cleavage, and may be a therapeutic target to treat patients with heart failure.

Although cell therapy shows great promise as a new therapeutic strategy for heart failure, its precise mechanisms remain unclear. Furthermore, the advantages of cell therapy over conventional cytokine therapy have yet to be clarified. This study was designed to compare the functional improvement achieved by cell therapy and cytokine therapy in both ischemic and nonischemic heart failure experimental models. Ischemic heart failure was induced by ligating the left anterior descending artery, and nonischemic heart failure was induced by an IP injection of doxorubicin, respectively, in mice. After establishing the heart failure models, mice were randomly given a single intramyocardial injection of 2 x 10(5) c-kit-positive bone marrow stem cells (cell therapy), hepatic growth factor (cytokine therapy), or PBS injection only (control). In the ischemic heart failure model, both cell therapy and cytokine therapy increased the vessel density significantly, inhibited apoptosis of myocytes, and decreased the fibrotic area in the ischemic myocardium, which resulted in a significant increase in the survival rate and enhancement of the cardiac function of these mice (p < 0.05 vs. control therapy). In the nonischemic heart failure model, significant increases in the survival rate and cardiac function were achieved by cell therapy (p < 0.05 vs. control therapy), but not by cytokine therapy, although cytokine therapy inhibited the fibrosis and apoptosis of the cardiomyocytes. Both cell therapy and cytokine therapy are alternative treatments for ischemic heart failure. However, cell therapy is more effective for the treatment of nonischemic heart failure than cytokine therapy achieved by the administration of a single growth factor.

Background: The Ca(2+) regulatory proteins in the sarcoplasmic reticulum (SR) play a key role in the pathogenesis of heart failure. In the present study the effect of chronic beta-receptor-stimulation on cardiac and SR functions was assessed, with or without angiotensin-II receptor antagonist treatment recently reported to have anti-beta-adrenergic activity., Methods and Results: Rats were treated with isoproterenol with (+) or without (-) candesartan (CAN) and then SR vesicles were isolated from the left ventricular muscle. Both Ca(2+)-uptake and the amount of SR Ca(2+)-ATPase were significantly lower in the CAN (-) group than in the shams, but those were almost normally restored in the CAN (+). Although the level of the protein kinase A (PKA)-phosphorylation of the SR Ca(2+) release channel, known as the ryanodine receptor (RyR2), was elevated in the CAN (-), no Ca(2+)-leak was detected. However, SIN-1 (O(2) (-) donor) induced Ca(2+)-leak in the CAN (-) at a 10-fold lower dose than in the sham and CAN (+). In cardiomyocytes, SIN-1 decreased cell shortening and the peak Ca(2+) transient and prolonged time from peak to 70% decline in CAN (-), again at 10-fold lower dose than in the sham and CAN (+)., Conclusion: Chronic beta-receptor-stimulation did not induce any Ca(2+)-leak from the SR, whereas Ca(2+)-leak was easily induced when oxidative stress was applied to the PKA-phosphorylated RyR2. Candesartan not only improved Ca(2+)-uptake, but also prevented PKA-phosphorylation, rendering the SR less susceptible to Ca(2+)-leak.

Abnormal regulation of intracellular Ca(2+) by sarcoplasmic reticulum plays a part in the mechanism underlying contractile and relaxation dysfunction in heart failure (HF). The protein-kinase-A-mediated hyperphosphorylation of ryanodine receptors in the sarcoplasmic reticulum has been shown to cause the dissociation of FKBP12.6 (also known as calstabin-2) from ryanodine receptors in HF. In addition, several disease-linked mutations in the ryanodine receptors have been reported in patients with catecholaminergic polymorphic ventricular tachycardia or arrhythmogenic right ventricular cardiomyopathy type 2. The unique distribution of these mutation sites has led to the concept that the interaction among the putative regulatory domains within the ryanodine receptors has a key role in regulating channel opening. The knowledge gained from various studies of ryanodine receptors under pathologic conditions might lead to the development of new pharmacological or genetic strategies for the treatment of HF or cardiac arrhythmia. In this review, we focus on the role of the Ca(2+)-release channel, the ryanodine receptor, in the pathogenesis of HF and fatal arrhythmia, and the possibility of developing new therapeutic strategies for targeting this receptor.

Background: Defective interdomain interaction within the ryanodine receptor (RyR2) seems to play a key role in the pathogenesis of heart failure, as shown in recent studies. In the present study we investigated the effect of oxidative stress on the interdomain interaction, its outcome in the cardiac function in heart failure, and the possibility of preventing the problem with antioxidants., Methods and Results: Sarcoplasmic reticulum (SR) vesicles were isolated from dog left ventricular (LV) muscle (normal or rapid ventricular pacing for 4 weeks with or without the antioxidant edaravone). In the edaravone-treated paced dogs (EV+), but not in the untreated paced dogs (EV-), normal cardiac function was restored almost completely. In the SR vesicles isolated from the EV-, oxidative stress of the RyR2 (reduction in the number of free thiols) was severe, but it was negligible in EV+. The oxidative stress of the RyR2 destabilized interdomain interactions within the RyR2 (EV-), but its effect was reversed in EV+. Abnormal Ca2+ leak through the RyR2 was found in EV- but not in EV+. The amount of the RyR2-bound FKBP12.6 was less in EV- than in normal dogs, whereas it was restored almost to a normal amount in EV+. The NO donor 3-morpholinosydnonimine (SIN-1) reproduced, in normal SR, several abnormal features seen in failing SR, such as defective interdomain interaction and abnormal Ca2+ leak. Both cell shortening and Ca2+ transients were impaired by SIN-1 in isolated normal myocytes, mimicking the pathophysiological conditions in failing myocytes. Incubation of failing myocytes with edaravone restored the normal properties., Conclusions: During the development of heart failure, edaravone ameliorated the defective interdomain interaction of the RyR2. This prevented Ca2+ leak and LV remodeling, leading to an improvement of cardiac function and an attenuation of LV remodeling.

The abnormally regulated release of Ca2+ from an intracellular Ca2+ store, the sarcoplasmic reticulum (SR), is the mechanism underlying contractile and relaxation dysfunctions in heart failure (HF). According to recent reports, protein kinase A (PKA)-mediated hyperphosphorylation of ryanodine receptor (RyR) in the SR has been shown to cause the dissociation of FK506 binding protein (FKBP) 12.6 from the RyR in heart failure. This causes an abnormal Ca2+ leak through the Ca2+ channel located in the RyR, leading to an increase in the cytosolic Ca2+ during diastole, prolongation of the Ca2+ transient, and delayed/slowed diastolic Ca2+ re-uptake. More recently, a considerable number of disease-linked mutations in the RyR have been reported in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT) or arrhythmogenic right ventricular dysplasia type 2. An analysis of the disposition of these mutation sites within well-defined domains of the RyR polypeptide chain has led to the new concept that interdomain interactions among these domains play a critical role in channel regulation, and an altered domain interaction causes channel dysfunction in the failing heart. The knowledge gained from the recent literature concerning the critical proteins and the changes in their properties under pathological conditions has brought us to a better position to develop new pharmacological or genetic strategies for the treatment of heart failure or cardiac arrhythmia. A considerable body of evidence reviewed here indicates that abnormal RyR function plays an important role in the pathogenesis of heart failure. This review also covers some controversial issues in the literature concerning the involvement of phosphorylation and FKBP12.6.

Background: Heart failure consists of two phenotypes: systolic heart failure and diastolic heart failure (DHF). A growing body of evidence demonstrated benefits of beta-blocker, angiotensin-converting enzyme inhibitor, and angiotensin II receptor blocker in systolic heart failure; however, evidence leading to therapeutic strategy of DHF is lacking., Methods and Results: The Japanese Diastolic Heart Failure Study (J-DHF) is a multicenter, prospective, randomized trial designed to assess effects of beta-blocker in patients with DHF. A total of 800 patients (400 patients in each group) will be enrolled. The primary outcome is a composite of cardiovascular death and unplanned admission to hospital for congestive heart failure. Other outcomes include all-cause mortality, worsening of the symptoms of heart failure, or a need for modification of the treatment for heart failure. Serial assessment of echocardiographic and neurohumoral parameters and cost analysis of the treatment regimen will be conducted. The follow-up period is a minimum of 2 years., Conclusion: This study will provide important evidences for the treatment of DHF.

Background: According to our hypothesis, 2 domains within the ryanodine receptor (RyR) of sarcoplasmic reticulum (SR) (N-terminal [0 to 600] and central [2000 to 2500] domains), where many mutations have been found in patients with polymorphic ventricular tachycardia, interact with each other as a regulatory switch for channel gating. Here, we investigated whether the defective FKBP12.6-mediated stabilization of RyR in heart failure is produced by an abnormal interdomain interaction., Methods and Results: SR vesicles were isolated from dog left ventricular muscles, and then the RyR moiety of the SR was fluorescently labeled with methylcoumarin acetate (MCA) using DPc10, a synthetic peptide corresponding to Gly2460-Pro2495 of RyR (one of the mutable domains in polymorphic ventricular tachycardia), as a site-directing carrier; the carrier was removed from the RyR after MCA labeling. Addition of DPc10 induced an unzipped state of the interacting N-terminal and central domains, as evidenced by an increase in the accessibility of the RyR-bound MCA fluorescence to a large fluorescence quencher. Domain unzipping resulted in Ca2+ leak through the RyR and facilitated cAMP-dependent hyperphosphorylation of RyR and FKBP12.6 dissociation from RyR. When DPc10 was introduced into the isolated myocytes, the magnitude of intracellular Ca2+ transient decreased, and its decay time was prolonged. In the SR isolated from pacing-induced dog failing hearts, the domain unzipping has already occurred, together with FKBP12.6 dissociation and Ca2+ leak., Conclusions: The specific domain interaction within the RyR regulates the channel gating property, and the defectiveness in the mode of the interdomain interaction seems to be the initial critical step of the pathogenesis of heart failure.

Sorcin is a 21.6-kDa Ca(2+) binding protein of the penta-EF hand family. Several studies have shown that sorcin modulates multiple proteins involved in excitation-contraction (E-C) coupling in the heart, such as the cardiac ryanodine receptor (RyR2), L-type Ca(2+) channel, and Na(+)-Ca(2+) exchanger, while it has also been shown to be phosphorylated by cAMP-dependent protein kinase (PKA). To elucidate the effects of sorcin and its PKA-dependent regulation on E-C coupling in the heart, we identified the PKA-phosphorylation site of sorcin, and found that serine178 was preferentially phosphorylated by PKA and dephosphorylated by protein phosphatase-1. Isoproterenol allowed sorcin to translocate to the sarcoplasmic reticulum (SR). In addition, adenovirus-mediated overexpression of sorcin in adult rat cardiomyocytes significantly increased both the rate of decay of the Ca(2+) transient and the SR Ca(2+) load. An assay of oxalate-facilitated Ca(2+) uptake showed that recombinant sorcin increased Ca(2+) uptake in a dose-dependent manner. These data suggest that sorcin activates the Ca(2+)-uptake function in the SR. In UM-X7. 1 cardiomyopathic hamster hearts, the relative amount of sorcin was significantly increased in the SR fraction, whereas it was significantly decreased in whole-heart homogenates. In failing hearts, PKA-phosphorylated sorcin was markedly increased, as assessed using a back-phosphorylation assay with immunoprecipitated sorcin. Our results suggest that sorcin activates Ca(2+)-ATPase-mediated Ca(2+) uptake and restores SR Ca(2+) content, and may play critical roles in compensatory mechanisms in both Ca(2+) homeostasis and cardiac dysfunction in failing hearts.

Background: Left ventricular end-diastolic pressure (LVEDP) is difficult to measure continuously; therefore, pulmonary capillary wedge pressure (PCWP) is frequently used instead for hemodynamic monitoring in patients with heart failure. However, a discrepancy between LVEDP and mean PCWP is sometimes observed., Methods and Results: To assess the feasibility of evaluating this discrepancy using echo-Doppler indexes, 140 consecutive patients with heart disease were studied. Transthoracic Doppler echocardiography (TTDE) was performed immediately before bilateral-sided cardiac catheterization. We measured peak velocities of early (E: cm/s) and late (A: cm/s) diastolic transmitral flow, and duration of A wave (MAd: ms). We also measured the duration of atrial reversal of pulmonary venous flow (PAd: ms). The difference between PAd and MAd (Deltad = PAd-MAd: ms) was calculated. The ratio of E to tissue Doppler-derived peak early diastolic velocity of mitral annulus (Ea: cm/s) was also calculated (E/Ea). There was a good positive correlation between LVEDP and Deltad (r = 0.77, p < 0.001). There was a modest correlation between mean PCWP and E/Ea (r = 0.56, p < 0.001). When patients were classified by Deltad > or = 10 ms and E/Ea < or = 14, elevated LVEDP (> or = 17 mmHg) and normal mean PCWP (< or = 12 mmHg) were predicted with 100% sensitivity and 85% specificity., Conclusions: Evaluation of the discrepancy between LVEDP and mean PCWP in patients with heart failure was feasible by separately estimating LVEDP by Deltad and mean PCWP by E/Ea using noninvasive TTDE. Early detection of patients with elevated LVEDP and normal mean PCWP may be useful for preventing acute exacerbation of chronic heart failure.

Background: Cardiac natriuretic peptides and echo-Doppler indexes are important as prognostic indicators of congestive heart failure (CHF). However, differences between etiologies have not been fully investigated. This study aimed to assess the prognostic value of transmitral flow (TMF) and B-type natriuretic peptide (BNP) on admission or predischarge in patients with acutely decompensated CHF of ischemic and nonischemic etiologies., Methods and Results: We studied 52 patients with chronic CHF, 31 with old myocardial infarction (OMI), and 21 with idiopathic dilated cardiomyopathy (DCM), admitted for emergency acute decompensation. Patients underwent echo-Doppler study and measurement of plasma BNP on admission and predischarge. The combined index of BNP with echo-Doppler indexes were calculated. Pulmonary capillary wedge pressure (PCWP) and cardiac index were measured on admission. All were followed for 1 year, and those rehospitalized (R group) were compared with those with a stable clinical course (S group). TMF and BNP on admission were similar between DCM and OMI groups. During follow up, 9 with OMI and 10 with DCM were rehospitalized. There were no statistical differences in TMF or BNP levels on admission between the R and S groups. However, the predischarge BNP level was significantly higher in the R group than in the S. Kaplan-Meier curves revealed the influence of predischarge BNP on prognosis., Conclusion: Predischarge BNP, not BNP on admission, levels are considered predictive of rehospitalization for decompensation within a year. There were no differences between BNP and echo-Doppler indexes with regard to the CHF etiology.

Background: Although angiotensin II receptor blockade is considered to be useful for the treatment of human heart failure, little beneficial hemodynamic effect has been shown in some experimental failing hearts. In this study, we assessed the effect of an angiotensin II receptor blocker, valsartan, on sarcoplasmic reticulum (SR) function, defectiveness of which is a major pathogenic mechanism in heart failure., Methods and Results: SR vesicles were isolated from dog left ventricular muscle (normal or exposed to 4-week rapid ventricular pacing with or without valsartan). In the untreated and valsartan-treated paced dogs, cardiac function showed similar deterioration (compared with before pacing). However, both the density of beta-receptors and the contractile response to dobutamine were greater in the valsartan-treated paced dogs than in the untreated paced dogs. In untreated paced hearts, the ryanodine receptor was protein kinase A-hyperphosphorylated, showed an abnormal Ca2+ leak, and had a decreased amount of ryanodine receptor-bound FKBP12.6. No such phenomena were seen in the valsartan-treated paced hearts. Both the SR Ca2+ uptake function and the amount of Ca2+-ATPase were decreased in the untreated failing SR, but both were restored in the valsartan-treated SR., Conclusions: During the development of pacing-induced heart failure, valsartan preserved the density of beta-receptors and concurrently restored SR function without improving resting cardiac function.

Background: The efficacy and optimum dose of beta-blockers have not been established in Japanese patients with chronic heart failure (CHF). The efficacy and safety of two doses of carvedilol, a beta-blocker with vasodilator and antioxidant actions, were investigated in Japanese patients with CHF., Methods: After screening and a carvedilol challenge phase, 174 patients with mild to moderate CHF were randomly assigned (double-blinded) to placebo, 2.5 mg of carvedilol twice daily, or 10 mg of carvedilol twice daily. After a 2- to 4-week uptitration phase, maintenance treatment was continued for 24 to 48 weeks. The primary end point was improvement of the global assessment of CHF by the attending physician. Secondary end points were death or hospitalization for cardiovascular disease, cardiovascular hospitalization, hospitalization for heart failure, change of left ventricular ejection fraction, and change in New York Heart Association class., Results: Carvedilol therapy achieved dose-dependent improvement of all end points (P for linear trend, range.002 to <.001). Both carvedilol groups showed marked risk reduction (71% to 91%) for cardiovascular and CHF hospitalization and for death or cardiovascular hospitalization (P range,.024 to <.001 for pairwise comparisons with placebo). No significant differences were observed for noncardiovascular hospitalization or adverse events., Conclusions: In Japanese patients with mild or moderate CHF, carvedilol achieved dose-related improvement of CHF and left ventricular ejection fraction; cardiovascular hospitalization was markedly reduced. At 5 mg/d, carvedilol conferred an important patient benefit, less than at 20 mg/d.

The CHARM programme, which recruited 7,601 patients, compared the angiotensin-receptor blocker, candesartan, with a placebo in three different populations with class II-VI heart failure. Candesartan reduced cardiovascular mortality and/or hospitalization for heart failure in patients with heart failure and ejection fractions of greater than 40% or less, and total mortality was reduced in these patients as well. Similar benefits were seen whether or not background therapy with ACE inhibitors, beta blockers', or spironolactone was used. Pooled analysis of the three studies showed that candesartan provided a significant reduction in cardiovascular death and also demonstrated a positive trend in the overall reduction in all cause mortality. The major adverse effects were hyperkalemia, increase in creatinine concentration and hypotension.

The Japanese Circulation Society have long been involved in the development of practice guidelines designed to assist physicians in the management of chronic heart failure. Importantly, as our population ages, the incidence of chronic heart failure and its mortality rate will continue to increase. Furthermore, recent advances in our understanding of the pathophysiology of chronic heart failure and new developments in the therapy of this disorder have greatly expanded the information base which to make decisions. The guidelines for the evaluation and management of chronic heart failure were developed by cardiovascular specialists and were based primarily on a comprehensive review of published reports. Furthermore, these guidelines are based on the assumption that the resources necessary to provide this care readily available.

Defective interaction between FKBP12.6 and ryanodine receptors (RyR) is a possible cause of cardiac dysfunction in heart failure (HF). Here, we assess whether the new cardioprotective agent JTV519 can correct it in tachycardia-induced HF. HF was induced in dogs by 4-wk rapid ventricular pacing, and sarcoplasmic reticulum (SR) was isolated from left ventricular muscles. In failing SR, JTV519 increased the rate of Ca(2+) release and [(3)H]ryanodine binding. RyR were then labeled in a site-directed fashion with the fluorescent conformational probe methylcoumarin acetamide. In failing SR, the polylysine induced a rapid change in methylcoumarin acetamide fluorescence, presumably because the channel opening preceding the Ca(2+) release was smaller than in normal SR (consistent with a decreased rate of Ca(2+) release in failing SR), and JTV519 increased it. In conclusion, JTV519, a new 1,4-benzothiazepine derivative, corrected the defective channel gating in RyR (increase in both the rapid conformational change and the subsequent Ca(2+) release rate) in HF.

Background: The development of heart failure is tightly correlated with a decrease in the stoichiometric ratio for FKBP12.6 binding to the ryanodine receptor (RyR) in the sarcoplasmic reticulum (SR). We report that a new drug, the 1,4-benzothiazepine derivative JTV519, reverses this pathogenic process. JTV519 is known to have a protective effect against Ca2+ overload-induced myocardial injury., Methods and Results: Heart failure was produced by 4 weeks of rapid right ventricular pacing, with or without JTV519; SR were then isolated from dog left ventricular (LV) muscles. First, in JTV519-treated dogs, no signs of heart failure were observed after 4 weeks of chronic right ventricular pacing, LV systolic and diastolic functions were largely preserved, and LV remodeling was prevented. Second, JTV519 acutely inhibited both the FK506-induced Ca2+ leak from RyR in normal SR and the spontaneous Ca2+ leak in failing SR. Third, there was no abnormal Ca2+ leak in SR vesicles isolated from JTV519-treated hearts. Fourth, in JTV519-treated hearts, both the stoichiometry of FKBP12.6 binding to RyR and the amount of RyR-bound FKBP12.6 were restored toward the values seen in normal SR. Fifth, in JTV519-untreated hearts, RyR was PKA-hyperphosphorylated, whereas it was reversed in JTV519-treated hearts, returning the channel phosphorylation toward the levels seen in normal hearts., Conclusions: During the development of experimental heart failure, JTV519 prevented the amount of RyR-bound FKBP12.6 from decreasing. This in turn reduced the abnormal Ca2+ leak through the RyR, prevented LV remodeling, and led to less severe heart failure.

Angiotensin receptor blocker(ARB) is expected to be a substitute of ACE inhibitor for ACE inhibitor(ACEi) incompetent patient or an additive drug for the treatment of severe heart failure. Two large mega-trials(ELITE II & Val-HEFT) have been reported so far and one large trial(CHARM) is ongoing. In ELITE II study, there was no additional beneficial effects of ARB compared to ACEi(captopril). On the other hand, additive ARB may be beneficial for most of patients with heart failure, according to the Val-Heft trial. However, some adverse effects of ARB by the combinatory use with ACEi and beta-blocker should be taken into careful consideration. Ongoing CHARM trial may answer if ARB is ultimately useful for the treatment of heart failure.

Background: In heart failure, protein kinase A-mediated hyperphosphorylation of ryanodine receptors (RyRs) in sarcoplasmic reticulum (SR) causes dissociation of FKBP12.6 from RyRs. This results in an abnormal Ca2+ leak through RyRs, possibly leading to cardiac dysfunction. In the present study, we assess whether beta-blockers can correct this defect in RyR in tachycardia-induced heart failure and thereby improve cardiac function., Methods and Results: SRs were isolated from dog left ventricular muscles (normal group, 4 weeks of rapid right ventricular pacing with or without propranolol [P(+) or P(-)]). End-diastolic and end-systolic diameters both increased less in P(+) than P(-), associated with a smaller decrease in fractional shortening in P(+). In SR from P(-), a prominent Ca2+ leak was observed, and FK506 (which dissociates FKBP12.6 from RyR) did not induce an additional Ca2+ leak. However, there was no appreciable Ca2+ leak in SR from P(+), although FK506 induced a Ca2+ leak as in normal SRs. In SR from P(+), an FK506-induced conformational change in RyR, which was virtually absent in SR from P(-), was observed as in normal SRs. Both the stoichiometry of FKBP12.6 versus RyR, assessed by [3H]FK506 and [3H]ryanodine binding assays, and the protein expression of FKBP12.6, assessed by Western blot analysis, were restored by propranolol toward the levels seen in normal SRs., Conclusions: Low-dose propranolol corrects the defective interaction of FKBP12.6 with RyR (restoration of RyR conformational change and prevention of Ca2+ leak from RyR), apparently resulting in an attenuation of intracellular Ca2+ overload and hence preventing the development of left ventricular remodeling in heart failure.