Clinical characteristics of responders to treatment with tolvaptan in patients with acute decompensated heart failure: Importance of preserved kidney size.

Background: Recent clinical trials have demonstrated the efficacy of short-term treatment with tolvaptan, an oral vasopressin V2 receptor antagonist, in patients with heart failure. However, the response to tolvaptan varies among patients. The aim of this study was to determine factors associated with response to tolvaptan in patients with acute decompensated heart failure (ADHF).

Influence of stochastic perturbation of both action updating and strategy updating in mixed-strategy 2×2 games on evolution of cooperation.

In a mixed-strategy game framework, each agent's strategy is defined by a real number; on the other hand, in a discrete strategy game framework, only binary strategies, either cooperation or defection, are allowed. In a spatial mixed-strategy game, with respect to the process for updating action (offer), either a synchronous or an asynchronous strategy update should be presumed. This study elucidates how stochastic perturbation that results from a synchronous or an asynchronous process for updating action significantly affects the enhancement of cooperation in an evolutionary process.

Direct reciprocity in spatial populations enhances R-reciprocity as well as ST-reciprocity.

As is well-known, spatial reciprocity plays an important role in facilitating the emergence of cooperative traits, and the effect of direct reciprocity is also obvious for explaining the cooperation dynamics. However, how the combination of these two scenarios influences cooperation is still unclear. In the present work, we study the evolution of cooperation in 2 × 2 games via considering both spatial structured populations and direct reciprocity driven by the strategy with 1-memory length.

SCN5A mutation is associated with early and frequent recurrence of ventricular fibrillation in patients with Brugada syndrome.

Background: Mutations in SCN5A are reportedly linked to Brugada syndrome (BS), but recent observations suggest that they are not necessarily associated with ventricular fibrillation (VF) in BS patients. Therefore, the clinical importance of SCN5A mutations in BS patients was examined in the present study.

Methods And Results:  The 108 BS patients were examined for SCN5A mutations and various parameters were compared between patients with and without mutations.

Abnormal restitution property of action potential duration and conduction delay in Brugada syndrome: both repolarization and depolarization abnormalities.

Aims: This study sought to examine the action potential duration restitution (APDR) property and conduction delay in Brugada syndrome (BrS) patients. A steeply sloped APDR curve and conduction delay are known to be important determinants for the occurrence of ventricular fibrillation (VF).

Methods And Results: Endocardial monophasic action potential was obtained from 39 BrS patients and 9 control subjects using the contact electrode method.

Atrial fibrillation in patients with Brugada syndrome relationships of gene mutation, electrophysiology, and clinical backgrounds.

Objectives: The goal of our work was to examine the relationships of atrial fibrillation (AF) with genetic, clinical, and electrophysiological backgrounds in Brugada syndrome (BrS).

Background: Atrial fibrillation is often observed in patients with BrS and indicates that electrical abnormality might exist in the atrium as well as in the ventricle. SCN5A, a gene encoding the cardiac sodium channel, has been reported to be causally related to BrS.

Idiopathic ventricular arrhythmias arising from the pulmonary artery: prevalence, characteristics, and topography of the arrhythmia origin.

Background: The characteristics of idiopathic ventricular tachycardias (VTs) or idiopathic premature ventricular contractions (PVCs) arising from the pulmonary artery (PA) have not been sufficiently clarified.

Objective: The purpose of this study was to clarify the prevalence, characteristics, and preferential sites of idiopathic VT/PVCs arising from the PA (PA-VT/PVCs).

Methods: Data obtained from 276 patients with idiopathic VT/PVCs who underwent radiofrequency (RF) catheter ablation were analyzed.

Usefulness of a long-straight sheath for atrial lead insertion at the right atrial septum.

Background: Pacing at the right atrial septum (RAS) appears to be superior to that performed at the right atrial appendage for preventing paroxysmal atrial fibrillation and for reducing complications. However, atrial lead insertion at the RAS is difficult and time-consuming. Although a few useful devices have been reported, handling of the atrial lead around the RAS is sometimes difficult even with those devices.

Efficacy and safety of the additional bepridil treatment in patients with atrial fibrillation refractory to class I antiarrhythmic drugs.

Background: Bepridil has multiple ion-channel blocking effects and is expected to be useful for managing atrial fibrillation (AF). The purpose of this study was to clarify the efficacy and safety of additional treatment with bepridil in patients with AF who had been treated with class I antiarrhythmic drugs (AADs).

Methods And Results: Bepridil (50-200 mg/day) was given to 76 patients with either paroxysmal (n=49) or persistent AF (n=27).

Plasma natriuretic peptide concentrations as a predictor for successful catheter ablation in patients with drug-refractory atrial fibrillation.

Background: The concentrations of atrial and brain natriuretic peptides (ANP and BNP) are elevated in patients with atrial fibrillation (AF), but the usefulness of their measurement before and after AF ablation has not been reported.

Methods And Results: The concentrations of the natriuretic peptides were evaluated in 54 patients undergoing catheter ablation for drug-resistant paroxysmal and persistent AF without heart failure. Based on the outcome, the patients were divided into 2 groups: successful (n=42) or failure (n=12).

Left atrial catheter ablation promotes vasoconstriction of the right coronary artery.

Background: Multiple cardiac ganglia are present in the left atrial (LA) region, and marked changes in autonomic nervous activity can occur after left atrial catheter ablation (CA) for atrial fibrillation (AF). Vasospastic angina involving the inferior wall of the left ventricle has been reported as a complication shortly after LACA.

Methods: We studied 20 patients with drug-refractory AF who underwent LACA, performed to encircle the left- and right-sided pulmonary veins, 1 to 2 cm from their ostia under fluoroscopic guidance.

Prevalence and characteristics of left atrial tachycardia following left atrial catheter ablation.

Background: Left atrial tachycardia (AT) is a complication of left atrial catheter ablation (LACA) of atrial fibrillation (AF). However, its prevalence and characteristics have not been sufficiently clarified.

Methods: We divided 121 patients who underwent LACA into 2 groups based on the results of AT occurrence after LACA (follow-up period; 12 +/- 7 months): an AT+ group and AT- group.

Ablation of idiopathic ventricular tachycardia in two separate regions of the outflow tract: prevalence and electrocardiographic characteristics.

Few studies have clarified the prevalence and characteristics of idiopathic outflow tachycardia (OT-VT) with an altered QRS morphology after radiofrequency catheter ablation (RFCA), requiring additional RFCA applications at a different portion of the outflow tract (OT) to abolish the OT-VT. Among 344 patients (97 VTs and 247 premature ventricular contractions), 12 (3.5%; VTs-7, PVCs-5; 6 women) had dynamic QRS morphology changes following the RFCA, requiring additional RFCA applications at a different portion to abolish the OT-VT.

Maximum ventricular dyssynchrony predicts clinical improvement and reverse remodeling during cardiac resynchronization therapy.

Background: Tissue synchronization imaging (TSI) and tissue tracking imaging (TTI) might facilitate the evaluation of ventricular dyssynchrony.

Methods: In 22 patients, TSI and TTI were performed before and < 1 month after onset of cardiac resynchronization therapy (CRT). With TSI guidance, maximum left ventricular (LV) intraventricular conduction delay (IVCDmax) was the greatest difference in time-to-peak velocity between septum and lateral wall.

Significance and utility of plasma brain natriuretic peptide concentrations in patients with idiopathic ventricular arrhythmias.

Background: Secretion of B-type natriuretic peptide (BNP) appears to be regulated mainly by wall tension, and an increase in the plasma BNP concentration is considered to reflect ventricular structural and functional abnormalities. The aim of this study was to clarify the significance and utility of the measurement of the plasma BNP in the setting of idiopathic ventricular arrhythmias (I-VT/PVCs).

Methods: This study included 135 patients with symptomatic, monomorphic I-VT/PVCs (73 women; 53 +/- 17 years; 50 ventricular tachycardias [VTs], 85 premature ventricular contractions) who underwent radiofrequency catheter ablation.

Idiopathic ventricular arrhythmias originating from the tricuspid annulus: Prevalence, electrocardiographic characteristics, and results of radiofrequency catheter ablation.

Background: Idiopathic ventricular tachycardias (VTs) and premature ventricular contractions (PVCs) arising from the tricuspid annulus have been reported.

Objective: The purpose of this study was to clarify the prevalence and characteristics of VT/PVCs originating from the tricuspid annulus.

Methods: The ECG characteristics and results of radiofrequency (RF) catheter ablation were analyzed in 454 patients with idiopathic VT/PVCs.

Percutaneous transvenous mitral commissurotomy and radiofrequency catheter ablation in patients with mitral stenosis.

Background: The purpose of this study was to evaluate the short- and long-term results of radiofrequency catheter ablation (RFCA) for the treatment of atrial fibrillation (AF) in patients with mitral stenosis (MS) following percutaneous transvenous mitral commissurotomy (PTMC).

Methods And Results: Four patients (2 males, age 59+/-6 years) underwent simultaneous PTMC and pulmonary vein (PV) ablation. All patient had AF and MS (2 had persistent AF >1 month, 2 had paroxysmal AF), and the mean duration of AF was 3.

Left atrial and pulmonary vein ostial ablation as a new treatment for curing persistent atrial fibrillation.

Background: Segmental pulmonary vein (PV) isolation has been performed to eliminate paroxysmal atrial fibrillation (AF). However, this technique is not effective in most patients with persistent AF.

Methods And Results: Left atrial catheter ablation (LACA) was performed by encircling the left- and right-sided PV 1-2 cm from the ostia, guided by an electroanatomical mapping system in 16 patients with persistent AF (>1 month).

Idiopathic premature ventricular contractions arising from the pulmonary artery: importance of mapping in the pulmonary artery in left bundle branch block-shaped ventricular arrhythmias.

A patient underwent radiofrequency (RF) catheter ablation of symptomatic idiopathic ventricular contractions (PVCs). RF energy applications at 2 sites in the right ventricular outflow tract (RVOT), where both the earliest ventricular activation and near-perfect pace mapping were obtained, did not abolish the PVC but resulted in changes in the QRS morphology of the PVC. Complete elimination of the PVC was achieved with RF energy application at a site within the pulmonary artery 13 mm above the pulmonary valve, which was greater than 20 mm away from the failed ablation sites within the RVOT.

Idiopathic ventricular arrhythmia arising from the mitral annulus: a distinct subgroup of idiopathic ventricular arrhythmias.

Objectives: We sought to clarify the prevalence and characteristics of idiopathic ventricular tachycardia or premature ventricular contraction originating from the mitral annulus (MAVT/PVC).

Background: Recent case reports have presented patients with MAVT/PVC.

Methods: Electrocardiographic (ECG) characteristics and the results of electrophysiologic investigation and radiofrequency catheter ablation (RFCA) were analyzed in 352 patients with symptomatic idiopathic ventricular tachycardia (IVT)/premature ventricular contraction (PVC).

Tissue tracking imaging as a new modality for identifying the origin of idiopathic ventricular arrhythmias.

Tissue tracking imaging was performed in 33 patients with idiopathic ventricular arrhythmias before radiofrequency catheter ablation. The site of the arrhythmia origin, defined as the site where the earliest color-coded signal appeared on the myocardium at the onset of the arrhythmia, corresponded to the site of origin as determined on fluoroscopy during activation mapping in all patients. Catheter ablation at that site abolished the arrhythmia in 29 patients (88%).

Tissue Doppler imaging and strain Doppler imaging as modalities for predicting clinical improvement in patients receiving biventricular pacing.

Background: The purpose of this study was to determine the utility and efficacy of tissue Doppler imaging (TDI) and strain Doppler imaging (SDI) for evaluating ventricular synchrony and function, and for predicting the long-term clinical improvement in patients undergoing biventricular pacing (BVP).

Methods And Results: TDI and SDI were performed before and <1 month after initiating BVP in 17 patients with advanced heart failure. An intraventricular conduction delay between the left ventricular (LV) septal and lateral walls was measured by TDI.

Sinus node function in patients with Brugada-type ECG.

Background: Some studies have shown that patients with Brugada syndrome (BS) have atrioventricular conduction disturbance, but their sinus node function has not been evaluated.

Methods And Results: The patients group consisted of 59 male patients and 1 female patient with BS. Supraventricular and ventricular programmed electrical stimulation (PES) was performed.