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Background Although epicardial structures around the atrium such as adipose tissue possess arrhythmogenicity, little is known about atrial tachycardias (ATs) originating from epicardial sites (Epi‐ATs). This study aimed to elucidate the prevalence, characteristics, and outcome after radiofrequency catheter ablation (RFCA) of Epi‐ATs and to reveal the association between Epi‐ATs and the epicardial structures. Methods The electrocardiographic, electrophysiologic, and anatomical properties and results of RFCA were analyzed in 42 patients with a total of 49 ectopic ATs. Results Six Epi‐ATs (12%) were observed in six patients (14%). Four of six were respiratory cycle‐dependent ATs and one was a swallowing‐induced AT. The Epi‐AT origins were adjacent to a pulmonary vein (five cases) and vein of Marshall (one case). A Valsalva maneuver or atropine infusion to define the arrhythmia mechanism affected the appearance of the Epi‐ATs. The congruity rate between epicardial adipose tissue and the AT origin was significantly higher (100% vs. 44%, p = .045), and the epicardial adipose tissue volume of the atrium was significantly larger (104.1 vs. 64.6 ml, p = .04) in the Epi‐AT group. Endocardial RFCA targeting the AT foci resulted in acute success in five of five cases. However, electrical isolation including of the AT foci resulted in acute failures (two of three cases) or a recurrence (one of one case). Conclusions Six Epi‐ATs were associated with thoracic veins and epicardial arrhythmogenic structures. The main cause provoking the Epi‐ATs was associated with autonomic nerve activity.

Evaluations of His bundle pacing (HBP) lead location at autopsy examination have been rarely reported. We report an autopsy case of a 98-year-old man who underwent HBP implantation due to atrioventricular block and heart failure. Although selective HBP was achieved with an acceptable threshold, the stimulus-to-QRS interval was relatively longer without correction of the right bundle-branch block. A macroscopic examination revealed that the HBP lead was inserted on the ventricular side passing through the anteroseptal commissure of the tricuspid valve. Transthyretin cardiac amyloidosis may affect the distal conduction system resulting in a long stimulus-to-QRS interval during selective HBP.

Key Clinical Message An EIM (ethanol infusion into the vein of Marshall [VOM]) provoked a fatal complication in a chronic hemodialysis patient. Autopsy revealed a lacerated VOM covered with thrombi as the only potential cause. The EIM caused vascular damage and clots resulting in myocardial necrosis and interstitial bleeding around the lacerated VOM.

The aortic root is a structure consisting of the lower part of the ascending aorta, sinotubular junction (STJ), annulus, cusps, aortic sinus of Valsalva, and coronary artery ostia. When considering the structure of the aortic root and its surroundings, confirming the structure of (1) the junction of the root of the pulmonary trunk (PT) with the right ventricular outflow tract (RVOT) as a basic concept makes it simpler to understand the precise structure of (2) the junction of the aortic root with the left ventricular outflow tract (LVOT).

Background— The existence of an atypical fast-slow (F/S) atrioventricular nodal reentrant tachycardia (AVNRT) including a superior (sup) pathway with slow conductive properties and an atrial exit near the His bundle has not been confirmed. Methods and Results— We studied 6 women and 2 men (age, 74±7 years) with sup-F/S-AVNRT who underwent successful radiofrequency ablation near the His bundle. Programmed ventricular stimulation induced retrograde conduction over a superior SP with an earliest atrial activation near the His bundle, a mean shortest spike-atrial interval of 378±119 milliseconds, and decremental properties in all patients. sup-F/S-AVNRT was characterized by a long-RP interval; a retrograde atrial activation sequence during tachycardia identical to that over a sup-SP during ventricular pacing; ventriculoatrial dissociation during ventricular overdrive pacing of the tachycardia in 5 patients or atrioventricular block occurring during tachycardia in 3 patients, excluding atrioventricular reentrant tachycardia; termination of the tachycardia by ATP; and a V-A-V activation sequence immediately after ventricular induction or entrainment of the tachycardia, including dual atrial responses in 2 patients. Elimination or modification of retrograde conduction over the sup-SP by ablation near the right perinodal region or from the noncoronary cusp of Valsalva eliminated and confirmed the diagnosis of AVNRT in 4 patients each. Conclusions— sup-F/S-AVNRT is a distinct supraventricular tachycardia, incorporating an SP located above the Koch triangle as the retrograde limb, that can be eliminated by radiofrequency ablation.

Left ventricular noncompaction (LVNC) is characterized by abnormally prominent trabeculations and deep intertrabecular recesses in the left ventricle.1 LVNC can range from asymptomatic to end-stage heart failure and lethal arrhythmias, which lead to sudden cardiac death. Mutations associated with sarcomere proteins, ion channels, and developmental transcription factors have been identified in patients with LVNC.1 The proband was diagnosed with incomplete right bundle branch block at 5 years old. At 16 years old, he was diagnosed with complete right bundle branch block and frequent premature ventricular contraction. At 25 years old, he was diagnosed with complete atrioventricular block and left ventricular dysfunction, and a permanent pacemaker was implanted. His echocardiogram exhibited prominent trabeculations and deep intertrabecular recesses in the apical to midventricular lateral wall. The noncompacted zone/compacted zone ratio was 2.3 (Figure A). Subsequently, symptoms of left ventricular dysfunction became progressively more severe despite medication and cardiac resynchronization therapy, and he eventually died of heart failure. The autopsy findings showed dilated ventricular lumen, whitish and filamentous prominent trabeculations in the ventricle, and thin compacted myocardium (Figure B). Microscopic findings showed displacement of the atrioventricular node by a fatty tissue (Figure C) and loss of the Purkinje fibers. Thickened endocardium and subendocardial fibrosis were seen, and fibrosis of trabeculae and interventricular septum were more prominent than previously reported cases.2 Mild anastomosing broad trabeculae and staghorn-like endocardial lined spaces were seen (Figure D). A fibrous band was not apparent. These findings were consistent with LVNC …

Recently, direct-acting oral anticoagulants (DOACs) have been introduced, with increasing use in patients with non-valvular atrial fibrillation (NVAF). However, warfarin continues to be widely used and the benefits and risks of warfarin in NVAF patients warrant closer inspection.Thromboembolism, major hemorrhage, and total and cardiovascular mortalities were analyzed in 7,406 NVAF patients in the J-RHYTHM Registry from January to July 2009, prior to DOAC introduction. Propensity score matching analysis was performed to reduce the differences in clinical characteristics between non-anticoagulant (n=1002) and warfarin (n=6404) cohorts to reassess warfarin outcomes over 2years.The incidence of thromboembolism was significantly greater in the non-anticoagulant cohort (3.0%) than in the warfarin cohort (1.5%, P0.001) with less frequent major hemorrhage in the non-anticoagulant cohort (0.8%) than in the warfarin cohort (2.1%, P=0.009). Using propensity score matching, new subsets (n=896 each) were obtained, with matching of the clinical characteristics between warfarin and non-anticoagulant subsets. The warfarin subset had lower risk factors compared with the total warfarin cohort. The incidence of thromboembolism was higher in the non-anticoagulant subset (2.9%) than in the warfarin subset (0.7%, P0.001). However, major hemorrhage was not significantly different between the two subsets.Although warfarin was associated with a significantly higher incidence of hemorrhage in the unmatched cohorts, propensity score matching revealed that warfarin reduced thromboembolism without a significant increase in hemorrhage in the matched subsets with lower risks. Propensity score matching reduced selection bias and provided rational comparisons although it had indwelling limitations.

A 58-year-old woman visited the emergency room for faintness on exertion 1 month after treatment of an atrial septal defect (ASD) by transcatheter closure (Amplatzer septal occluder [ASO], St. Jude Medical, St. Paul, Minnesota). An electrocardiogram showed advanced atrioventricular (AV) block ([

With the development of technology for electrophysiological procedures, the importance of understanding the cardiac anatomy has increased not only for interpreting the information obtained from electroanatomical mapping of the heart but also for analyzing the mechanisms of arrhythmias [1, 2]. It goes without saying that a great deal of anatomical knowledge concerning the cardiac anatomy has already been accumulated in various kinds of textbooks. These textbooks have naturally provided us with very important information regarding imaging the cardiac structures [3]. However, this anatomical knowledge does not seem sufficient for cardiologists, particularly, electrophysiologists, as it fails to provide a complete image of the cardiac structures. Electrophysiologists require not the name of these anatomical structures but practical images of the structures for use in various clinical situations.

Treatment guidelines for atrial fibrillation (AF) used in Western countries describe female gender as a risk factor for thromboembolic events in patients with nonvalvular AF (NVAF). The present study aimed to determine the impact of gender on prognosis of Japanese patients with NVAF. A subanalysis of 7,406 patients with NVAF (mean age 70 years) who were followed-up prospectively for 2 years was performed using data from the J-RHYTHM registry. The primary end points were thromboembolic events, major hemorrhaging, total mortality, and cardiovascular mortality. Compared with male subjects (n = 5,241), female subjects (n = 2,165) were older and displayed greater prevalences of paroxysmal AF, heart failure, and hypertension but less prevalences of diabetes, previous cerebral infarction, and coronary artery disease. Male and female patients had mean CHADS2 (Congestive heart failure, Hypertension, Age of 75 years or more, Diabetes mellitus and prior Stroke or transient ischemic attack) scores of 1.6 and 1.8, respectively (p0.001). Warfarin was given to 87% of male patients and 86% of female patients (p = 0.760), and the 2 genders displayed similar mean international normalized ratio of prothrombin time values at baseline (1.91 vs 1.90, respectively, p = 0.756). Multivariate logistic regression analysis indicated that male gender was an independent risk factor for major hemorrhaging (odds ratio 1.59, 95% confidence interval 1.05 to 2.40, p = 0.027) and all-cause mortality (odds ratio 1.78, 95% confidence interval 1.25 to 2.55, p0.002) but not for thromboembolic events (odds ratio 1.24, 95% confidence interval 0.83 to 1.86, p = 0.297) or cardiovascular mortality (odds ratio 0.96, 95% confidence interval 0.56 to 1.66, p = 0.893). In conclusion, female gender is not a risk factor for thromboembolic events among Japanese patients with NVAF who were treated mostly with warfarin. However, male gender is a risk factor for major hemorrhaging and all-cause mortality.

We describe a 38-year-old male who experienced several episodes of syncope after having ventricular fibrillation. The electrocardiographic monitoring after his hospitalization revealed repetitive polymorphic ventricular tachycardias. All polymorphic ventricular tachycardias were consistently initiated by a short-coupled monomorphic ventricular premature contraction (VPC). This VPC was suggested to originate from the inferoposterior region of the right ventricle (RV). Radiofrequency catheter ablation targeting the VPC was successfully performed, and the CARTO merge system (Biosense Webster Inc., Diamond Bar, CA, USA) revealed that the culprit region was the root of the posterior papillary muscle of the RV. A subsequent follow-up of 15 months has been uneventful.

Background: Currently, β -blockers are used most frequently for the purpose of heart rate (HR) control in patients with atrial fibrillation (AF) in worldwide. Carvedilol is one of common β -blockers and known to be effective for hypertension and heart failure. However, little can be found the information about the HR-lowering effect of carvedilol in patients with AF without heart failure. Therefore, we conducted this study to investigate the effect of carvedilol on HR in 3-minute electrocardiogram (ECG) and total heart beats (THBs) in 24-hour Holter ECG monitoring in patients with persistent or permanent AF. Methods: A total of 13 hypertensive patients (73 ± 12 years, 7 males) with AF and HR 90 bpm or more were enrolled. All patients received carvedilol from 5 mg/day. The dose of drug was titrated every 4 weeks and raised to 10 or 20 mg/day if HR was 80 bpm or more. Results: Mean HR was decreased from 101.9 ± 13.9 to 85.2 ± 15.2 bpm (P < 0.05) after treatment with carvedilol. THBs were also significantly decreased from 128 to 115 × 1,000/day (P < 0.001). Percent reduction in HR and THBs were 13.9% and 10.7%, respectively. The scores of Atrial Fibrillation Quality of Life Questionnaire (AFQLQ) did not change. Only one patient was required to discontinue carvedilol due to congestive heart failure. Conclusions: We observed that carvedilol certainly reduced HR in patients with chronic AF. We believe that the effect of carvedilol on the reduction in HR can contribute to the management of AF patients treated with rate-control strategy. doi: http://dx.doi.org/10.4021/jocmr1581w

Ridge-Related Reentry Introduction The ridge between the left pulmonary veins (PV) and the left atrial appendage composes part of the lateral mitral isthmus (LMI). Following circumferential PV isolation and LMI linear ablation for the treatment of atrial fibrillation (AF), a critical pathway might develop over the ridge leading to a ridge-related reentry (RRR). Methods and Results Out of 61 patients who underwent circumferential PV isolation appended by LMI ablation, 5 patients developed RRR. The diagnosis of RRR was based on (1) macro-reentrant atrial tachycardia involving the septum, anterior and inferior wall of the left atrium; (2) slow conduction along the ridge; (3) wide-split double potentials in the ventricular aspect of the LMI were identified with the coronary sinus (CS) electrodes. RRR was investigated with electroanatomical mapping and entrainment mapping and catheter ablation was carried out in all patients. The mean cycle length (CL) of RRR was 312 ± 82 milliseconds and the PPIs at the left atrial septum, inferior and anterior wall during RRR were 10 ± 6, 12 ± 8, 9 ± 5 milliseconds longer than the RRR CL. The interval of the double potentials recorded in the CS electrodes crossing the LMI was 164 ± 38 milliseconds during RRR and the PPI on the LMI near the mitral annulus was 57 ± 10 milliseconds longer than the RRR CL. Catheter ablation was performed anatomically by targeting the ridge and successfully terminated RRR. Conclusion After circumferential PV isolation and ablation for LMI in patients with AF, RRR can develop by utilizing the surviving myocardial tissue of the ridge as a critical pathway.

Background: Target anticoagulation levels for warfarin in Japanese patients with non-valvular atrial fibrillation (NVAF) are unclear. Methods and Results: Of 7,527 patients with NVAF, 1,002 did not receive warfarin (non-warfarin group), and the remaining patients receiving warfarin were divided into 5 groups based on their baseline international normalized ratio (INR) of prothrombin time (≤1.59, 1.6–1.99, 2.0–2.59, 2.6–2.99, and ≥3.0). Patients were followed-up prospectively for 2 years. Primary endpoints were thromboembolic events (cerebral infarction, transient ischemic attack, and systemic embolism), and major hemorrhage requiring hospital admission. During the follow-up period, thromboembolic events occurred in 3.0% of non-warfarin group, but at lower frequencies in the warfarin groups (2.0, 1.3, 1.5, 0.6, and 1.8%/2 years for INR values of ≤1.59, 1.6–1.99, 2.0–2.59, 2.6–2.99, and ≥3.0, respectively; P=0.0059). Major hemorrhage occurred more frequently in warfarin groups (1.5, 1.8, 2.4, 3.3, and 4.1% for INR values ≤1.59, 1.6–1.99, 2.0–2.59, 2.6–2.99, and ≥3.0, respectively; P=0.0041) than in non-warfarin group (0.8%/2 years). These trends were maintained when the analyses were confined to patients aged ≥70 years. Conclusions: An INR of 1.6–2.6 is safe and effective at preventing thromboembolic events in patients with NVAF, particularly patients aged ≥70 years. An INR of 2.6–2.99 is also effective, but associated with a slightly increased risk in major hemorrhage. (UMIN Clinical Trials Registry UMIN000001569) (Circ J 2013; 77: 2264–2270)

BACKGROUND The proportion of patients with atrial fibrillation (AF) treated with anticoagulation varies from country to country. In Japan, little is known about regional differences in frequency of warfarin use or prognosis among patients with non-valvular AF (NVAF). METHODS AND RESULTS In J-RHYTHM Registry, the number of patients recruited from each of 10 geographic regions of Japan was based on region population density. A total of 7,406 NVAF patients were followed up prospectively for 2 years. At baseline, significant differences in various clinical characteristics including age, sex, type of AF, comorbidity, and CHADS2score, were detected among the regions. The highest mean CHADS2score was recorded in Shikoku. Frequency of warfarin use differed between the regions (P

A 68-year-old man died a few days after catheter ablation of drug-resistant, monomorphic ventricular tachycardia (VT) complicated with cardiac sarcoidosis. The diagnosis of mitral isthmus VT was made from electrophysiological observations, including electro-anatomical activation and voltage map, pace-mapping, entrainment mapping and ablation outcome. On autopsy of the heart, sarcoidic lesion with scattered fibrous tissue in the mitral isthmus was non-transmural, and the surviving myocardium serving as the reentry circuit in the endomyocardium was isolated from the adjacent viable epimyocardium, enabling the sustenance of macroreentry across the mitral isthmus. Non-transmural lesions produced by RF delivery created a barrier sufficient to interrupt the myocardial bundles located in the mitral isthmus, eliminating the mitral isthmus VT.

A combination therapy of a low-dose antihypertensive diuretic with an angiotensin II receptor blocker (ARB) may have unfavorable effects on serum urate levels.Forty-two hypertensive patients without hyperuricemia (18 men and 24 women, mean age 65 years) were randomly divided into three groups. Each of the group was allocated to a combination therapy with losartan (LOS; CAS 124750-99-8; 50 mg/day)/hydrochlorothiazide (HCTZ; CAS 58-93-5; 12.5 mg/day) (LOS/HCTZ group), telmisartan (TEL; CAS 144701-48-4; 40 mg/day)/HCTZ (12.5 mg/day) (TEL/HCTZ group), or candesartan (CND; CAS 145040-37-5; 8 mg/day)/HCTZ (12.5 mg/day) (CND/HCTZ group), respectively. Before and after the treatment, blood pressure and biochemical parameters of blood and urine were evaluated.Both systolic and diastolic blood pressures significantly decreased in all groups (p0.01) without any statistical differences. The LOS/HCTZ group showed no changes in serum urate levels (5.8 +/- 1.0 mg/dl to 5.8 +/- 1.4 mg/dl) and in % fractional excretion of urate (FEUA). In the TEL/HCTZ group, the serum urate level was significantly increased, from 5.5 +/- 0.9 mg/dl to 6.5 +/- 1.2 mg/dl (p0.01), whereas FEUA significantly decreased (p0.01). Similarly, the CND/HCTZ group showed a significant increase in the serum urate level from 5.4 +/- 0.9 mg/dl to 6.0 +/- 1.2 mg/dl (p0.01) and a significant decrease in FEUA (p0.01). No significant differences were found in fasting plasma glucose and electrolytes levels in any of the groups.A combination therapy with a low-dose HCTZ and ARBs resulted in reduced urate excretion and elevated serum urate levels. A combination therapy with the ARB losartan was not accompanied with these effects, likely because of its inhibitory action on urate transporter 1. The study limitations deserve mention in consideration of ethic restrictions, small size, short term examination and uncontrolled design.

We investigated the effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the stability of Kv1.5 channel protein. The expression and function of Kv1.5 (Kv1.5-FLAG) in transfected African green monkey kidney fibroblast cells as well as rat atrium were estimated by immunoblotting, immunoprecipitation, immunofluorescence and patch-clamp techniques. Both EPA and DHA immediately blocked Kv1.5 channel current in a dose-dependent manner, accompanied by reduction of their phosphorylation. Chronic treatment (for 12 h) with EPA at lower concentrations (0.3-10 muM) increased the level of Kv1.5-FLAG protein as well as Kv1.5 channel current without changes in its gating kinetics, prolonging its half-life; in contrast, both EPA and DHA at higher concentrations (30-100 muM) decreased the expression of Kv1.5-FLAG. EPA at the higher concentrations also decreased mRNA of Kv1.5 and synapse-associated protein 97 expression. EPA at the lower concentrations increased Kv1.5 expression in the endoplasmic reticulum, Golgi apparatus and cell membrane. EPA-induced increase of Kv1.5 channel expression and current was abolished by pretreatment with the protein transport inhibitor brefeldin A or colchicines, and by the Kv1.5 channel blocker 4-aminopyridine. Oral administration of EPA (30 mg/kg) increased the level of endogenous Kv1.5 in rat atria. These results indicate that chronic treatment with EPA at lower concentrations stabilizes Kv1.5 channel protein in the endoplasmic reticulum and Golgi apparatus thereby enhancing the Kv1.5 channel current on the cell membrane.

Context: Pendrin is an apical protein of thyroid follicular cells, responsible for the efflux of iodide into the follicular lumen via an iodide-chloride transport mechanism. It is unknown whether pendrin is recognized by autoantibodies. Objective: Our objective was to examine the prevalence of pendrin antibodies in autoimmune thyroid diseases and compare with that of thyroglobulin, thyroperoxidase, TSH receptor, and sodium iodide symporter antibodies. Design: In a prevalent case-control study, we analyzed the sera of 140 autoimmune thyroid disease cases (100 with Graves’ disease and 40 with Hashimoto’s thyroiditis) and 80 controls (50 healthy subjects, 10 patients with papillary thyroid cancer, 10 with systemic lupus erythematosus, and 10 with rheumatoid arthritis). Pendrin antibodies were measured by immunoblotting using extract of COS-7 cells transfected with pendrin and a rabbit polyclonal pendrin antibody. Results: Pendrin antibodies were found in 81% of the cases and 9% of controls (odds ratio = 44; P < 0.0001). Among cases, pendrin antibodies were more frequent and of higher titers in Hashimoto’s thyroiditis than in Graves’ disease. Pendrin antibodies correlated significantly with thyroglobulin, thyroperoxidase, and sodium iodide symporter antibodies but not with TSH receptor antibodies. Pendrin antibodies were equally effective as thyroglobulin and thyroperoxidase antibodies in diagnosis of autoimmune thyroid diseases, especially Hashimoto’s thyroiditis. Conclusions: The study identifies pendrin as a novel autoantigen recognized by patients with autoimmune thyroid diseases and proposes the use of pendrin antibodies as an accurate diagnostic tool.

Background: Risk stratification for elderly patients with acute decompensated heart failure (ADHF) may help clinicians to select the appropriate therapy and raise the quality of care. Methods and Results: The present study enrolled 349 patients aged over 65 years who were hospitalized with ADHF from January 2004 to October 2008. Five independent prognostic factors were identified by multivariate logistic regression analysis, and each factor was assigned a number of points proportional to its regression coefficient: prior heart failure hospitalization (2points), sodium ≤138 mmol/L (2points), BUN ≥35 mg/dl (2points), albumin ≤3.2 g/dl (3points), and BNP ≥980 pg/ml (2points); in particular, hypoalbuminemia was identified as the strongest prognostic factor. The patients were stratified into 3 groups: low risk (0-4points), moderate risk (5-7points), and high risk (8-11points). The respective in-hospital mortality rates were 1.6%, 15.8%, and 42.1% (P

The ubiquitin-proteasome system is responsible for the disappearance of truncated cardiac myosin-binding protein C, and the suppression of its activity contributes to cardiac dysfunction. This study investigated whether missense cardiac myosin-binding protein C gene (MYBPC3) mutation in hypertrophic cardiomyopathy (HCM) leads to destabilization of its protein, causes UPS impairment, and is associated with cardiac dysfunction. Mutations were identified in Japanese HCM patients using denaturing HPLC and sequencing. Heterologous expression was investigated in COS-7 cells as well as neonatal rat cardiac myocytes to examine protein stability and proteasome activity. The cardiac function was measured using echocardiography. Five novel MYBPC3 mutations -- E344K, DeltaK814, Delta2864-2865GC, Q998E, and T1046M -- were identified in this study. Compared with the wild type and other mutations, the E334K protein level was significantly lower, it was degraded faster, it had a higher level of polyubiquination, and increased in cells pretreated with the proteasome inhibitor MG132 (50 microM, 6 h). The electrical charge of its amino acid at position 334 influenced its stability, but E334K did not affect its phosphorylation. The E334K protein reduced cellular 20 S proteasome activity, increased the proapoptotic/antiapoptotic protein ratio, and enhanced apoptosis in transfected Cos-7 cells and neonatal rat cardiac myocytes. Patients carrying the E334K mutation presented significant left ventricular dysfunction and dilation. The conclusion is the missense MYBPC3 mutation E334K destabilizes its protein through UPS and may contribute to cardiac dysfunction in HCM through impairment of the ubiquitin-proteasome system.

Background The angiotensin receptor blocker losartan inhibited urate transporter 1 (URAT1) according to in vitro experiments. However, it is still unknown whether the inhibitory effect of losartan on URAT1 contributes to its uricosuric action in humans. Methods Thirty-two patients with hypertension and nine patients with idiopathic renal hypouricemia (five with and four without hypertension) were enrolled for this study. Hypertensive patients were prescribed oral losartan (50 mg/day, n = 16) or candesartan (8 mg/day, n = 16). Before and after 1-month treatment, the serum concentration of urate (Sur) and creatinine (Scr), and the clearance value of urate (Cur) and creatinine (Ccr) were determined. Clearance studies using the URAT1 inhibitor benzbromarone (100 mg/day) or losartan (50 mg/day) loading test were also performed in these patients. Results Blood pressure (BP) significantly decreased in the patients treated with either losartan or candesartan. Losartan significantly reduced Sur, which was associated with a concomitant increase in the Cur/Ccr ratio, whereas candesartan did not alter these parameters. In hypertensive patients with loss-of-function mutation of URAT1, losartan did not alter either Sur or Cur/Ccr, nor did benzbromarone. The lack of effect of URAT1 inhibitors on renal excretion of urate was independent of the renal function of hypouricemic patients. On the other hand, both losartan and benzbromarone increased Cur/Ccr ratio in hypertensive patients harboring the wild URAT1 gene, regardless of the presence of hypouricemia. Conclusions These findings suggested that losartan inhibited URAT1 and thereby it lowered Sur levels in hypertensive patients.

The aim of this study was to elucidate the mechanisms for regulations of cardiac Kv1.5 channel expression. We particularly focused on the role of heat shock proteins (Hsps). We tested the effects of Hsps on the stability of Kv1.5 channels using biochemical and electrophysiological techniques: co-expression of Kv1.5 and Hsp family proteins in mammalian cell lines, followed by Western blotting, immunoprecipitation, pulse-chase analysis, immunofluorescence and whole-cell patch clamp. Hsp70 and heat shock factor 1 increased the expression of Kv1.5 protein in HeLa and COS7 cells, whereas either Hsp40, 27 or 90 did not. Hsp70 prolonged the half-life of Kv1.5 protein. Hsp70 was co-immunoprecipitated and co-localized with Kv1.5-FLAG. Hsp70 significantly increased the immunoreactivity of Kv1.5 in the endoplasmic reticulum, Golgi apparatus and on the cell membrane. Hsp70 enhanced Kv1.5 current of transfected cells, which was abolished by pretreatment with brefeldin A or colchicine. Thus, Hsp70, but not other Hsps, stabilizes functional Kv1.5 protein.

Aims To compare the risk of atrioventricular (AV) conduction disturbance between patients with sinus node dysfunction on AAI pacing who had a low or high Wenckebach block rate (WBR). Methods and results Patients with sinus node dysfunction and normal AV conduction those underwent an electrophysiological study were studied. The patients were classified into two groups: Group L was with the patients with a WBR of 100 to 129 per minute and Group H was with the patients with a WBR ≥ 130 per minute. All patients followed up every 3–6 months after an AAI pacemaker implantation. A total of 102 patients, including 35 Group L and 67 Group H, were followed for 90 ± 44 months. Six patients died from non-cardiac cause and five patients required a new atrial lead implantation due to lead failure during follow-up. Symptomatic bradycardia requiring a new ventricular lead implantation developed in four patients (annual incidence 0.5%). In Group L, two patients developed AV block (annual incidence 0.7%). In Group H, two patients developed bradycardic atrial fibrillation (annual incidence 0.4%). Kaplan–Meier analysis revealed no significant difference between the two groups ( P = 0.2983). Conclusion These results suggest that a long-term risk of developing AV conduction disturbance is low even in patients with a WBR of 100 to 129 per minute.

左房前壁の構造的特徴を剖検心35例で検討した.全例において, 左房前壁右縁近傍に卵円窩とほぼ同じレベルで, ほぼ同じ面積の楕円形で照射光を透過するほどに壁の薄いtranslucent area (TA) を認めた.従来報告のなかったこの構造物周囲を太い筋肉束transverse myocardial bundle (TMB) が取り囲んでいた.このTMBは前壁左縁では左心耳一上肺静脈間を走行する稜と連絡し, 前壁右縁ではBachmann束と連絡していた.さらにTMB内あるいは近傍に沿って左から右に冠動脈左房枝が走行していた.左房前壁に対するカテーテルアブレーション治療の報告がみられるようになっているが, 今回, われわれが確認した構造物の存在を理解することは左房前壁に対するカテーテルアブレーションに伴う合併症を回避する意味でも, 同部位における電気生理学的特性を検討するうえでも重要と考えられた.

We report a novel action of intracellular adenosine monophosphate (AMP) to inhibit β-adrenergic signaling in isolated rat ventricular myocytes. Extracellular application of adenosine or AMP suppressed isoproterenol (Iso)-induced prolongation of action potential duration (APD). This effect was completely abolished by an A 1 -receptor antagonist, DPCPX. Intracellular application of AMP, but not adenosine, attenuated Iso-induced APD prolongation. Iso-induced increases in the L-type Ca 2+ current (I Ca,L ) were also inhibited by intracellular AMP. These inhibitory effects were not affected by either DPCPX or glibenclamide. In vitro, AMP directly inhibited PKA activity via binding to its regulatory subunit. These results suggest that intracellular AMP attenuates β-adrenergic signaling by directly inhibiting PKA activity, independently of A 1 -purinergic receptor.

Although ischemia-induced neovascularization is reportedly impaired with aging, the effect of aged-bone marrow mononuclear cells (BM-MNCs) on neovascularization has not been investigated. The neovascularization capacity of BM-MNCs obtained from 8-week-old mice (young) was compared to those obtained from 18-month-old mice (old), both in vivo and in vitro. Neovascularization in ischemic limbs was significantly impaired in old mice. Whereas transplantation of young BM-MNCs significantly improved blood perfusion, tissue capillary density, and vascular endothelial growth factor (VEGF) production in transplanted ischemic limbs, no such effects were observed with old BM-MNCs. Old BM-MNCs also showed a significant impairment of in vitro VEGF production and migratory capacity in response to VEGF. The number of Dil/lectin-positive cells was significantly lower in old mice, but there was no difference in the number of AC133(+)/CD34(+) and CD34(+)/VEGF-R2(+) positive cells between young and old BM-MNCs. Transplantation of young BM-MNCs improved neovascularization and VEGF production in the ischemic limbs of old recipients, with results that were similar to those obtained in young recipients. These results indicate that the neovascularization capacity of transplanted BM-MNCs is impaired with aging. However, aging does not hamper the revitalization of neovascularization in the murine host in response to transplantation of young BM-MNCs.

Background Remote reperfusion lung injury occurs in patients with vascular occlusion and surgical procedures. Inosine monophosphate (IMP) produced by adenosine monophosphate deaminase (AMPD) 3 is involved in the remote reperfusion injury. The purpose of the present study was to identify whether IMP administration attenuated the remote reperfusion lung injury in a skeletal muscle ischemia-reperfusion model. Methods and Results A remote reperfusion lung injury was created using reperfusion after the bilateral ligation of the hind-limb. AMPD activity, myeloperoxidase (MPO) activity, IMP, AMPD3 mRNA and tumor necrosis factor (TNF)-α in the lungs before and after reperfusion were analyzed. Furthermore, the effects of IMP on these parameters were examined. AMPD3 mRNA, AMPD activity and IMP production in the lungs significantly increased after ischemia-reperfusion with increases in MPO activity, TNF-α level and decreased oxygen saturation (SpO2). Histological examination of the lungs demonstrated significant neutrophil infiltration and accumulation. IMP administration significantly reduced MPO activity, TNF-α and neutrophil infiltration, with ameliorated SpO2. Conclusions Along with the activation of AMPD3, ischemia-reperfusion-induced lung inflammation is associated with increased MPO activity and TNF-α level. IMP significantly decreased the lung injury, MPO activity, TNF-α and increased SpO2. These findings may lead to the development of a new therapeutic strategy for remote reperfusion lung injury. (Circ J 2007; 71: 591 - 596)

Hyperuricemia in hypertensive subjects has been considered one of risk factors of cardiovascular diseases. We investigated the status of uric acid management in 799 hypertensive subjects (432 females and 367 males; mean age 70.9 years) managed by 43 doctors (19 cardiologists and 24 noncardiologists; 25 private practice doctors and 18 hospital doctors). The serum uric acid level was available in 85.7% of the patients. This availability was equivalent regardless of facility size, and more cardiologists than noncardiologists monitored this information. The prevalence of hyperuricemia was 17.5% and was higher in men and in patients with high triglyceridemia, left ventricular hypertrophy, renal dysfunction, proteinuria, and smokers, but was not higher in subjects with chronic heart failure, diabetes mellitus, and those with prescriptions for diuretics and beta-blockers. The average serum uric acid level was higher in men and patients with chronic heart failure, renal dysfunction, high triglyceridemia, low high-density cholesterolemia, smokers, and subjects prescribed beta-blockers. Fifty percent of hyperuricemic patients were medicated, and 48.6% of them cleared the uric acid target level (6 mg/dL). No differences were observed in the treatment rate or the achievement rate of the target between genders, concurrent diseases, and physician specialties. Although doctors, especially cardiologists, have a high concern for the serum uric acid level, they do not intervene intensively, and specific treatment for individual patterns is not routinely given. Thus, more attention to uric acid management is necessary in hypertensive subjects to prevent cardiovascular diseases.

Background The inferior vena cava (IVC) is obliquely connected to the right atrium (RA), and often a low-voltage area is observed in the posteroinferior RA. Objectives The purpose of this study was investigate the size of the IVC extension into RA and its anatomic background. Methods We investigated 30 human hearts [11 men and 19 women; mean age 79 ± 10 years; 7 cardiac deaths (group A) and 23 noncardiac deaths (group B)]. After obtaining macroscopic measurements around the RA–IVC junction, serial sections were cut and examined histologically. We defined a horizontal baseline at the level of the cavotricuspid isthmus and measured (1) the length of IVC extension, which was defined as the distance from the baseline to the top of the RA–IVC junction, and (2) the width of the RA–IVC junction at the baseline level. Results The top of the RA–IVC junction was always located in the posteroinferior RA. The mean length of the IVC extension was 17.6 ± 6.6 mm, and the mean width was 29.6 ± 7.5 mm. The IVC extension was wider in group A than in group B (35.8 ± 9.0 mm vs 27.5 ± 5.9 mm; P = .0277). The right and left borders of the RA–IVC junction corresponded to the reflection of the pericardium. Histologic examination showed no myocardium in the IVC extension. Conclusion The IVC extension into the posteroinferior RA always exists and varies in size. Because this area lacks myocardium, it is important to consider when analyzing catheter mapping from this area.

Background Adenosine 5′-triphosphate is catabolized to adenosine 5′-monophosphate (AMP), which is further degraded by 2 pathways: deamination to inosine 5′-monophosphate and ammonia by AMP deaminase, or dephosphorylation to adenosine and inorganic phosphate by 5′-nucleotidase. Because adenosine is believed to be cardioprotective and we have reported that ammonia production decreased after exercise in patients with chronic heart failure (CHF), we determined if plasma adenosine levels after exercise increases in patients with CHF. Methods and Results Maximal ergometer exercise tests with expired gas analysis were performed in 51 patients with CHF (age = 61 ± 2 years, New York Heart Association [NYHA] class I/II/III = 19/18/14) and 20 age-matched normal controls. Serial changes in both plasma ammonia and adenosine levels were determined. The ratio for Δammonia to peak work rate became smaller (control, NYHA I/II/III: 0.59 ± 0.13/0.41 ± 0.06/0.37 ± 0.10/0.22 ± 0.11 μg/dL·watts, respectively) and the ratio for Δadenosine to peak work rate was significantly higher in class III CHF (control, NYHA I/II/III: 0.93 ± 0.21/0.86 ± 0.14/1.11 ± 0.27/2.92 ± 0.67 nmol/L·watts, respectively). Conclusion In patients with CHF after exercise, the plasma levels of adenosine increased along with the decrease in the plasma levels of ammonia. Considering the physiologic cardioprotective actions of adenosine, the enhanced adenosine production after exercise may be an important adaptive response in patients with CHF.

We report the case of a 74-year-old man with Fontaine stage IV chronic arteriosclerosis obliterans who had been suffering from inveterate giant skin ulcers on the dorsum and heel of the right foot. As conventional medical treatments had not improved these ulcers and surgical treatment was considered unfeasible, amputation of the right lower limb below the knee appeared to represent the only option. The patient was admitted to Tottori University Hospital to attempt a new angiogenic therapy using auto-mononuclear cell transplantation to avoid amputation. On admission, neither right ankle blood pressure nor transcutaneous partial pressure of oxygen at the right toe were detectable. The patient had a history of multiple cerebral infarctions, and collection of mononuclear cells from bone marrow was considered too difficult, so collection of peripheral blood mononuclear cells was selected. Transcutaneous partial pressure of oxygen and skin temperature in the treated limb started to improve from 2 weeks after implantation. Ulcer size was recognizably reduced by 1 month after treatment. Partial auto-skin implantation on the right heel was performed 2 months after treatment, and the giant skin ulcer was finally completely covered. No adverse effects were noted during follow-up lasting 1 year. These results suggest that peripheral blood mononuclear cell implantation may offer a suitable alternative rescue therapy for patients with critical limb ischemia whose general condition is not good.

We report the case of a 67-year-old woman with severe hypertension caused by an extra-adrenal pheochromocytoma. The tumor was detected by 131I metaiodobenzylguanidine scintigraphy and it was found to be small (2 cm ø) by enhanced CT. After the extirpation of the tumor, the blood pressure of the patient immediately normalized. It should be taken into account that a small extra-adrenal pheochromocytoma can be one of the causes of secondary hypertension in elderly patients. Since small extra-adrenal pheochromocytomas are difficult to detect, it is also important to perform suitable examinations to establish the diagnosis. Furthermore, we emphasize the importance of an accurate diagnosis in elderly patients with pheochromocytoma, for they often have less symptomatology and more severe cardiovascular complications due to refractory hypertension than younger patients.

Uric acid and oxidative stress promote cardiovascular diseases, including atherosclerosis and hypertension. Xanthine oxidase, through which uric acid is generated, is a free-radical generating enzyme. The aim of the current study was to investigate whether allopurinol, an inhibitor of xanthine oxidase activity, affects vascular remodeling and vascular smooth muscle cell (VSMC) proliferation. In the carotid artery ligation model using spontaneously hypertensive rats (SHR), treatment with allopurinol induced a reduction in the neointima/media ratio by 27% (38.5+/-34.3% in the control group and 28.1 20.8% in the allopurinol-treated group, respectively, p

Background The voltage-gated potassium channel Kv1.5 plays a critical role in the maintenance of the membrane potential. While protein degradation is one of the major mechanisms for the regulation of channel functions, little is known on the degradation mechanism of Kv1.5. Methods and results Kv1.5 was expressed in COS cells and its degradation, intracellular localization, and channel activities were assessed by pulse-chase analysis, immunofluorescence, and patch clamp techniques, respectively. Expressed Kv1.5 had a half-life time of ∼6.7 h, which was prolonged by the proteasome inhibitors of MG132, ALLN, proteasomal inhibitor 1, or lactacystine, but not by a lysosomal inhibitor chloroquine. MG132 increased the protein level of Kv1.5, as well as the level of its ubiquitinated form in a dose-dependent manner. Similar effects of MG132 on endogenous Kv1.5 were seen in cultured rat atrial cells. Within a cell, Kv1.5 was mainly localized in both the endoplasmic reticulum and Golgi apparatus. MG132 increased the immunoreactivity of Kv1.5 in these compartments and also increased Ikur currents through the cell-surface Kv1.5. Pretreatment with either brefeldin A or colchicine abolished MG132-induced increase in Ikur currents. Conclusion Kv1.5 is degraded by the proteasome. The inhibition of the proteasome increased Ikur currents secondary to stabilization of the channel protein in the endoplasmic reticulum/Golgi apparatus.

ATP-sensitive K+ channels (KATP:SUR2A+Kir6.2) play a pivotal role in cardiac protection against ischemia and reperfusion injury. When expressed in COS cells, Kir6.2 was short-lived with a half-life time of 1.9 h. The half-life time of Kir6.2 was prolonged by proteasome inhibitors MG132, ALLN, proteasome inhibitor 1, and lactacystine, but not at all by a lysosomal inhibitor chloroquine. MG132 also increased the level of ubiquitinated Kir6.2 without affecting its localization in the endoplasmic reticulum and Golgi apparatus. In electrophysiological recordings, MG132 augmented nicorandil-activated KATP currents in COS cells expressing SUR2A and Kir6.2 as well as the same currents in neonatal rat cardiomyocytes. Like MG132, a Na+ channel blocker aprindine prolonged the half-life time of Kir6.2 and augmented KATP. Finally, both aprindine and MG132 inhibited the 20S proteasome activity in vitro. These results suggest a novel activity of aprindine to enhance KATP currents by inhibiting proteasomal degradation of Kir 6.2 channels, which may be beneficial in the setting of cardiac ischemia.

Angiotensin II (Ang II) has been reported to indirectly influence atrial electrical activity and to play a critical role in atrial arrhythmias in hypertensive patients. However, it is unclear whether Ang II has direct effects on the electrophysiological activity of the atrium affected by hypertension. We examined the effects of Ang II on the action potentials of atrial myocytes enzymatically isolated from spontaneous hypertensive rats (SHRs). The action potentials were recorded by the perforated patch-clamp technique and the atrial expression of the receptors AT1a and AT2 was measured by radioimmunoassay. Ang II significantly shortened the action potential durations (APDs) of SHRs without changes in the resting membrane potentials (RMPs). Pretreatment with selective AT1a blockers abolished the Ang II-induced reduction of atrial APDs of SHRs; however, a selective AT2 blocker did not, which was consistent with the results of the receptor assay. Pretreatment with phosphatidylinositol 3 (PI3)-kinase inhibitor, phospholipase C inhibitor, or protein kinase C (PKC) inhibitor abolished the Ang II-induced shortening of atrial APDs, but pertussis toxin and protein kinase A (PKA) inhibitor did not. To study the effects of chronic AT1a inhibition on Ang II-induced shortening of atrial APD, SHRs were treated with AT1a blocker for 4 weeks. AT1a blocker abolished the Ang II-induced reduction of atrial APDs of SHRs and also significantly lowered their blood pressure. In conclusion, Ang II shortened atrial APDs of SHRs via AT1a coupled with the Gq-mediated inositol triphosphate (IP3)-PKC pathway. Our findings indicated that Ang II caused atrial arrhythmias in hypertensive patients by shortening the effective refractory period of the atrium.