Yuya Aoyama

Angiotensin II-mediated up-regulation of connective tissue growth factor promotes atrial tissue fibrosis in the canine atrial fibrillation model

Aims Remodelling of the extracellular matrix (ECM) plays an important role in the production of arrhythmogenic substrate for atrial fibrillation (AF), and is considered to be promoted by the connective tissue growth factor (CTGF). Our objective was to assess the relationship between CTGF and ECM synthesis, and the effect of olmesartan on these processes. Methods and results Fifteen canine AF models were produced by rapid atrial stimulation. They were divided into three groups: pacing control (n = 5): 6-week pacing, pacing + olmesartan (n = 5): pacing with olmesartan (2 mg/kg/day), and non-pacing group (n = 5). In the pacing control group, messenger ribonucleic acid expressions of CTGF and collagen types 1 and 3 were up-regulated in comparison with the non-pacing group (P < 0.05) while transforming growth factor-β (TGF-β) did not exhibit a significant difference. In the pacing + olmesartan group, these up-regulations were suppressed (P < 0.05). In fluorescent immunostaining, the expression of CTGF was localized in the cytoplasm. The protein level of collagen type 3 was increased in the pacing control and it was suppressed in the pacing + olmesartan group. Conclusions CTGF and associated genes were up-regulated in the atria with the appearance of fibrosis. Because this up-regulation was independent of TGF-β and suppressed by olmesartan, CTGF up-regulation was considered to be mediated by angiotensin II.

Evaluation of the impact of atrial fibrillation on rehospitalization events in heart failure patients in recent years

BACKGROUND Although we have previously reported that the presence of paroxysmal atrial fibrillation (AF) is an independent risk factor for rehospitalization in patients with congestive heart failure (CHF) in a population from 1996 to 2002, the impact of AF configuration as a risk factor in a more recent population remains to be clarified. METHODS AND RESULTS 319 patients with CHF admitted to our institute in 2006-2007 were retrospectively evaluated. The patients were divided into 3 groups in accordance with their basic cardiac rhythm, i.e. sinus rhythm (n=210), chronic AF (n=68), and paroxysmal AF (n=41). During the follow-up period of 19 ± 17 months, there was no significant difference in mortality or rehospitalization events among the 3 groups (p=0.542). In the multivariate analysis, no administration of β-blockers was the only independent risk factor for rehospitalization due to CHF exacerbation. CONCLUSIONS The clinical impact of AF configuration as a risk factor of rehospitalization due to CHF exacerbation was considered to be decreased in recent years.

Long-term efficacy of catheter ablation for paroxysmal atrial fibrillation in patients with Brugada syndrome and an implantable cardioverter-defibrillator to prevent inappropriate shock therapy

BACKGROUND In patients with an implantable cardioverter-defibrillator (ICD) and Brugada syndrome (BrS), the long-term efficacy of catheter ablation for preventing inappropriate shock therapy due to paroxysmal atrial fibrillation (PAF) has not been elucidated. OBJECTIVE To evaluate the efficacy of atrial fibrillation (AF) ablation for PAF for prevention of inappropriate ICD therapy over a longer follow-up period. METHODS We enrolled 76 men with BrS and an ICD, with a mean age of 46.2 ± 16.5 years. Twenty-one patients had AF (19 had PAF, 1 had persistent AF, and 1 had longstanding persistent AF). Fourteen patients with PAF underwent pulmonary vein isolation (PVI) and received follow-up electrophysiological study (EPS) 6 months after the first PVI. If necessary, ablation was performed. RESULTS Over a mean follow-up period of 3.3 ± 1.4 years after the repeat session, 13 of the 14 patients (92.9%) had no recurrence of AF. Six patients with PAF without inappropriate ICD therapy before PVI had no recurrence of AF and no inappropriate therapy during follow-up. Among the 8 patients who had inappropriate therapy because of PAF before PVI, 1 patient who had recurrent AF underwent another ablation session. After this final session, there were no recurrences of AF and no inappropriate therapy (mean follow-up period 3.1± 1.2 years). CONCLUSION Catheter ablation is effective in patients with BrS and an ICD, and prevents inappropriate ICD therapy owing to PAF; thus, catheter ablation is an appropriate first-line therapy for PAF among such patients.

Early repolarization pattern and its day-to-day dynamic change as markers for ventricular fibrillation in patients with vasospastic angina.

AIMS An early repolarization (ER) pattern is a risk factor for ventricular fibrillation (VF) in certain diseases. However, it is unclear whether this association holds for patients with vasospastic angina (VSA). Moreover, the reported long-term follow-up of implantable cardioverter defibrillator (ICD) therapy for VSA patients is limited to 3 years. This study aimed to clarify the relation between ER and VF in patients with VSA and to investigate the long-term outcomes of ICD therapy. METHODS AND RESULTS This retrospective, observational survey evaluated 265 consecutive VSA patients, including 21 with VF. Their electrocardiogram findings and clinical course were analysed over a mean follow-up of 5.5 ± 3.3 years. Early repolarization was observed in 64 patients (24.2%) and was more frequent in patients with VF history than those without (P = 0.001). Early repolarization was independently associated with VF history. During follow-up, four patients had VF recurrences. Ventricular fibrillation recurrence was higher in patients with ER (log-rank, P = 0.018) or VF history (log-rank, P < 0.001) than those without. Among patients with ER, day-to-day variations in ER (P = 0.003) and notching of ER pattern (P = 0.03) were associated with VF history. Cases with day-to-day variation showed a higher incidence of VF recurrence during follow-up (log-rank, P = 0.007). During long-term follow-up, 23.5% of patients with an ICD received appropriate shock therapy. CONCLUSION The presence of ER, especially with day-to-day variation, can help predict VF recurrence in VSA patients. Implantable cardioverter defibrillator implantation is a reasonable approach for the secondary prevention of VF in high-risk VSA patients.

Usefulness of epicardial impedance evaluation for epicardial mapping and determination of epicardial ablation site for ventricular tachycardia: A pilot study

During epicardial mapping, determination of appropriate ablation sites in low voltage areas (LVA) is challenging because of large epicardial areas covered by adipose tissue.

Sodium Bicarbonate-Ascorbic Acid Combination for Prevention of Contrast-Induced Nephropathy in Chronic Kidney Disease Patients Undergoing Catheterization

BACKGROUND Sodium bicarbonate and ascorbic acid have been proposed to prevent contrast-induced nephropathy (CIN). The present study evaluated the effect of their combined use on CIN incidence.Methods and Results:We prospectively enrolled 429 patients with chronic kidney disease (CKD: baseline estimated glomerular filtration rate <60 mL/min/1.73 m2) prior to elective coronary catheterization. CIN was defined as absolute (≥0.5 mg/dL) or relative (≥25%) increase in serum creatinine within 72 h. In the saline hydration (n=218) and combined sodium bicarbonate+ascorbic acid (n=211) groups, a total of 1,500-2,500 mL 0.9% saline was given before and after the procedure. In addition, the combination group received 20 mEq sodium bicarbonate and 3 g ascorbic acid i.v. before the procedure, followed by 2 g ascorbic acid after the procedure and a further 2 g after 12 h. There were no significant differences between the basic characteristics and contrast volume in the 2 groups. CIN occurred in 19 patients (8.7%) in the saline group, and in 6 patients (2.8%) in the combined treatment group (P=0.008). CONCLUSIONS Combined sodium bicarbonate and ascorbic acid could prevent CIN following catheterization in CKD patients.

Author's reply: To PMID 22429679.

I read with great interest the article by Murakami et al. entitled Evaluation of the impact of atrial fibrillation on rehospitalization vents in heart failure patients in recent years” [1]. The authors concluded that the clinical impact of atrial fibrilation as a risk factor for rehospitalization due to congestive heart ailure exacerbation was considered to have decreased in recent ears and mentioned that no administration of -blockers was the nly independent risk factor for rehospitalization in the Cox hazrd multivariate analysis. The study is interesting, but I believe that ome comments regarding the results of the multivariate analysis re warranted. They showed the results of univariate and multivariate analses of the risk factors for rehospitalization in Table 2. They sed the odds ratio as the statistical parameter, but in the Cox roportional hazard model, hazard ratio is usually used. (Odds atio is used in the logistic regression model analysis.) The conrmation of the method of regression model adopted is firstly arranted. Second, they also showed the 95% confidential interval (CI) of he odds ratio of the parameters. For example, odds ratio of age s 0.148 and its 95% CI is −0.062 to 0.0063 (Table 2). However oth odds ratio and hazard ratio are quite unlikely to be negaive values. I wonder 95% CI of what actually is shown. Third, they howed that non-administration of -blocker was the only indeendent risk factor for rehospitalization. However the odds ratio s 0.614, indicating that non-administration of -blocker inhibits he occurrence of the events. Finally, in the multivariate Cox proortion hazard model and multivariate logistic regression analysis, variable per 10 events or more is strongly recommended [2]. n the present study, 17 variables per 99 events, i.e. 1 variable er 5.8 events was assigned. Since it may cause overfitting of staistical analysis, the number of independent variables should be educed. Thus, I hope the authors would reconsider the present results f multivariate analysis and perform the multivariate statistical nalysis again.

Long-term observation of fibrillation cycle length in patients under angiotensin II receptor blocker therapy for chronic atrial fibrillation

The long‐term effect of angiotensin II receptor blockers (ARBs) on atrial fibrillation (AF) is unclear. In this study, we evaluated the change in the fibrillation cycle length (FCL) in patients under long‐term ARB therapy for chronic AF.

Usefulness of ST elevation score by using vector-projected virtual 187-channel ECG for risk stratification in patients with Brugada-type ECG pattern

Although powerful defibrillation devices are available in clinical practice, risk stratification is important in asymptomatic Brugada syndrome. In this study, vector‐projected 187‐channel electrocardiogram (VP‐ECG) was used to calculate the ST‐elevation score in Brugada‐type ECG and test its usefulness in risk stratification.

Preventive Effect of Amiodarone on VT/VF Events in ICD Patients with Structural Heart Diseases

Background: Although amiodarone (AMD) is applied for implantable cardioverterdefibrillator (ICD) patients to reduce VT/VF events, its actual benefit and long‐term efficacy are unclear. In the present study, we retrospectively evaluated the incidence of VT/VF events in ICD patients with and without AMD.