Publications by authors named "Ryo Nishinarita"

Article Synopsis
  • Researchers conducted cavotricuspid isthmus (CTI) linear ablation to treat atrial flutter but saw no change in the tachycardia cycle length afterward.
  • In these situations, additional ablation techniques are typically employed to address the issue.
  • The team utilized high-density three-dimensional mapping post-ablation, uncovering a complex tachycardia circuit involving both the epicardial and endocardial layers.
View Article and Find Full Text PDF

Background: Atrial fibrillation (AF) is associated with an increased risk of heart failure (HF), stroke, and death. Although fibrillation cycle length (FCL) is used as a surrogate for atrial refractoriness, its impact on outcomes remains unclear. This study aimed to identify predictors of cardiovascular events, including FCL, in patients with long-standing persistent AF.

View Article and Find Full Text PDF

The recurrence of atrial fibrillation (AF) after catheter ablation (CA) is still an unsolved issue. Although structural remodeling is relatively well defined, the method to assess electrical remodeling of the atrium is not well established. In this study, we evaluated the relationship between atrial conduction properties and recurrence after CA for AF.

View Article and Find Full Text PDF
Article Synopsis
  • - New research shows that patients with cardiac implantable electronic devices (CIEDs) experience a higher rate of new atrial high-rate episodes (AHRE) compared to the general population, suggesting these patients may be at increased risk.
  • - The study analyzed 101 patients and found that those with AHRE had a greater presence of sick sinus syndrome and significantly longer P-wave dispersion (PWD) compared to those without AHRE.
  • - P-wave dispersion emerged as a strong, independent predictor of new-onset AHRE, providing useful metrics for clinicians to identify at-risk patients based on PWD measurements from electrocardiograms.
View Article and Find Full Text PDF
Article Synopsis
  • - The study aimed to evaluate the effectiveness of a new measure called optimized lesion size index (o-LSI) in achieving successful first-pass pulmonary vein isolation (PVI) in atrial fibrillation patients, as traditional measures sometimes fail.
  • - An analysis of data from 35 patients revealed that insufficient ablation sites (IAS) were significantly linked to higher bipolar voltage but not to the standard lesion size index (LSI), with the o-LSI showing promise in predicting IAS.
  • - A threshold o-LSI value of 2.04 was identified as having good potential for predicting IAS, suggesting that using o-LSI could enhance the success rate of PVI procedures.
View Article and Find Full Text PDF

The wearable cardioverter defibrillator (WCD) has been available since 2014 in Japan, and its benefit in the in-hospital acute phase at high risk of ventricular tachyarrhythmia (VTA) has been established, but its clinical use in the outpatient setting remains unclear, especially in Japan. The subjects consisted of 43 consecutive patients with WCD use in the outpatient setting from April 2014 to October 2019 at the present institute. Event alerts and wearing compliance were checked via the remote monitoring system, and a dedicated WCD training team contacted the patients if necessary.

View Article and Find Full Text PDF

Background: Right ventricular (RV) pacing causes left ventricular (LV) dyssynchrony sometimes resulting in pacing-induced cardiomyopathy. However, RV pacing for hypertrophic obstructive cardiomyopathy is one of the treatment options. LV flow energy loss (EL) using vector flow mapping (VFM) is a novel hemodynamic index for assessing cardiac function.

View Article and Find Full Text PDF

Background Recent clinical trials have demonstrated the possible pleiotropic effects of SGLT2 (sodium-glucose cotransporter 2) inhibitors in clinical cardiovascular diseases. Atrial electrical and structural remodeling is important as an atrial fibrillation (AF) substrate. Methods and Results The present study assessed the effect of canagliflozin (CAN), an SGLT2 inhibitor, on atrial remodeling in a canine AF model.

View Article and Find Full Text PDF

Background: Gastric hypomotility (GH) is a possible complication of catheter ablation (CA) for atrial fibrillation (AF). However, it is unclear which factors are associated with GH. We sought to elucidate the relationship between the CA procedure and GH.

View Article and Find Full Text PDF

Purpose: Ablation index (AI) is a useful tool of the CARTO® system to make effective lesions during pulmonary vein isolation (PVI) for atrial fibrillation (AF). However, the optimal distance between neighboring ablation points (interlesion distance (ILD)) is still unclear. Here, we evaluated the optimal ILDs in the AI-guided PVI.

View Article and Find Full Text PDF

We prospectively collected device and heart rate data through remote monitoring (RM) of patients with an implantable cardioverter defibrillator (ICD). The objective was to identify the predictors of lethal arrhythmic events (VT/VF).Thirty-three patients (mean age: 50 years) with ICDs [with functionality of heart rate variability (HRV) analysis] were divided into two groups [VT/VF (+), VT/VF (-) ].

View Article and Find Full Text PDF

Complex atrial tachycardias (ATs) after catheter ablation or a MAZE procedure is sometimes difficult to determine the circuits of the tachycardia. A high-density, grid-shapes mapping catheter has been launched, which can be useful for detecting the detail circuits of tachycardias on three-dimensional mapping systems. The signal quality is also important for performing electrophysiological studies (EPSs), such as entrainment mapping, to identify the circuit.

View Article and Find Full Text PDF

A 61-year-old male was referred to our hospital to receive catheter ablation of paroxysmal atrial fibrillation. Since no anatomical abnormalities were detected by preoperative computed tomography of left atrium and pulmonary veins (PVs), he underwent a cryoballoon ablation for a PV isolation. We performed single, 3-min freeze applications to all four PVs while monitoring the esophageal temperature.

View Article and Find Full Text PDF

Optimal antithrombotic strategy for atrial fibrillation (AF) patients with a history of percutaneous coronary intervention (PCI) has been under debate. The actual prescription trend of antithrombotic therapy for these patients remains unclear, especially in chronic phase.Patients with AF having at least a 1-year history of PCI were retrospectively evaluated in 2010, 2012, 2014, and 2016.

View Article and Find Full Text PDF

A 57-year-old man was admitted to our hospital due to syncopal attack. He was diagnosed with Brugada syndrome due to which a subcutaneous implantable cardiac defibrillator (S-ICD) was inserted using the standard technique. Two hours after the implantation, he experienced inappropriate shock while conscious.

View Article and Find Full Text PDF

Esophageal injury is a major concern during catheter ablation of atrial fibrillation. Operators avoid radiofrequency applications on the esophagus by changing ablation line; however, it is unavoidable in patients with a dilated esophagus, such as esophageal achalasia. Steerable esophageal thermometer is useful for evaluating precise temperatures to prevent esophageal injury.

View Article and Find Full Text PDF

Ventricular capture management is an automatic pacing threshold adjustment algorithm that automatically measures pacing threshold through detection of the evoked response after a pacing stimulus. Although it is principally designed to save device battery under the maintenance of the patient׳s safety, we experienced a rare case with serious pacing failure due to a weakness of this algorithm. This pacing failure might be explained by a large variation in the ventricular pacing threshold depending on the atrioventricular interval and daily variation of pacing threshold and concomitant steroid use in this patient.

View Article and Find Full Text PDF

Background: Dabigatran etexilate (DE), an effective direct oral anticoagulant for patients with atrial fibrillation (AF), should be carefully used in patients with renal insufficiency. Data on the safety of DE in Japanese "real world" patients with mildly impaired renal function are limited. We hypothesized that low-dose DE (110mg, twice daily) could be safely used in Japanese AF patients with mildly impaired renal function compared to those with preserved renal function.

View Article and Find Full Text PDF