Publications by authors named "Miki Yokokawa"
Background: Arrhythmias originating from papillary muscles (PAPs) can be challenging when targeted with catheter ablation. The prevalence and impact of structural abnormalities on PAPs in patients with focal PAP arrhythmias is unknown.
Objectives: The purpose of this study was to analyze, in a consecutive patient series with focal PAP arrhythmias, the impact of structural abnormalities detected by multimodality imaging.
Article Synopsis
- - Dofetilide, a class III antiarrhythmic, is used to treat atrial fibrillation and flutter, and has been applied off-label for ventricular arrhythmias like PVCs and VTs.
- - In a study involving 81 patients, dofetilide initiation showed a significant decrease in PVC burden, but was discontinued in some cases due to QT prolongation and lack of efficacy.
- - Overall, 72% of patients had to stop dofetilide due to inefficacy or intolerance, and there was no significant difference in event-free survival between those treated with dofetilide and those who weren't.
Background: Patients may develop atrial tachycardia (AT) after left atrial (LA) ablation of persistent atrial fibrillation (AF).
Methods: The population consisted of 101 consecutive patients (age = 64.3 ± 8.
Background: Patients with arrhythmias originating from papillary muscles (PAPs) often have pleomorphic ventricular arrhythmias (PVAs) that can result in failed ablations. The mechanism of PVAs is unknown.
Objective: The purpose of this study was to assess the prevalence and mechanisms of PVAs and the impact on outcomes in patients with focal left ventricular PAP ventricular arrhythmias (VAs).
Article Synopsis
- - The study focused on how the anatomy of papillary muscles (PAPs) relates to the mapping and successful ablation of ventricular arrhythmias (VAs) in patients.
- - Among 43 patients with frequent PAP arrhythmias, 40% had VAs originating from connections between PAPs and the surrounding myocardium, showing distinct electrocardiographic patterns.
- - Results indicated that patients with a higher number of PAP-myocardial connections (PAP-MYCs) had higher failure rates during ablation procedures, highlighting the importance of detailed anatomical imaging in treatment success.
Article Synopsis
- The study investigates the unintended isolation of the left atrial appendage (LAA) during radiofrequency ablation for persistent atrial fibrillation (AF) and its impact on long-term thromboembolic risk.
- It involved analyzing 41 patients with incidental LAA isolation and comparing thromboembolic occurrences to a matched group of 82 patients without such isolation over an average follow-up of 4.2 years.
- Results showed that patients with LAA isolation had a significantly higher rate of thromboembolism (17%) compared to those without (4%), highlighting the need to consider the risks of LAA isolation in treatment plans.
Article Synopsis
- Monitored anesthesia care (MAC) and general anesthesia (GA) are two methods used during catheter ablation for atrial fibrillation (AF), each with its own pros and cons.
- A study involving 810 patients found no significant differences in complications or long-term outcomes between MAC and GA, although GA resulted in longer anesthesia times and slightly higher costs.
- Ultimately, both methods showed similar effectiveness and safety in achieving sinus rhythm post-ablation when proper anesthesiology protocols were followed.
Introduction: Ventricular tachycardia (VT) in structurally normal hearts or nonischemic cardiomyopathy can originate from the aortic sinuses of Valsalva (SoV). It is unknown whether VT can originate from the SoVs in patients with prior myocardial infarction (MI).
Objective: To evaluate the prevalence, arrhythmogenic substrate, and ablation outcomes of postinfarction VT originating from the SoVs.
Article Synopsis
- * Out of 113 patients treated, 45% had their AF successfully terminated, with some also showing improvements in areas like the right atrium (RA).
- * On average, 78% of patients remained free from AF after 24 months without needing antiarrhythmic medications, suggesting the method's effectiveness.
Aims: Catheter ablation is an effective treatment for post-infarction ventricular tachycardia (VT). However, some patients may experience a worsened arrhythmia phenotype after ablation. We aimed to determine the prevalence and prognostic impact of arrhythmia exacerbation (AE) after post-infarction VT ablation.
View Article and Find Full Text PDFBackground: Frequent premature ventricular complexes (PVCs) can result in PVC-induced cardiomyopathy (PICM). Scarring has been described in patients with frequent PVCs in the absence of apparent heart disease and in patients with known cardiomyopathy.
Objective: The purpose of this study was to determine the impact of focal myocardial scarring as detected by cardiac magnetic resonance imaging (CMR) on PICM, procedural outcomes, and recovery of left ventricular function in patients with frequent PVCs.
Objectives: The goal of this study was to assess the value of a stepwise, image-guided ablation approach in patients with cardiomyopathy and predominantly intramural scar.
Background: Few reports have focused on catheter-based ventricular tachycardia (VT) ablation strategies in patients with predominantly intramural scar.
Methods: The study included patients with predominantly intramural scar undergoing VT ablation.
Article Synopsis
- Patients with nonischemic cardiomyopathy (NICM) often have heart issues that need treatment, but accessing the right area can be tricky.
- This study looked at a method using the coronary venous system (CVS) to help treat these patients instead of going through more complicated areas.
- Results showed that in some patients, treatment within the CVS helped fix the heart issue without needing extra procedures, especially if the damaged area was close to the CVS.
Background: Fibro-inflammatory processes in the extracellular matrix are closely associated with progressive structural remodeling in atrial fibrillation (AF). Serum concentrations of tenascin-C (TNC), an extracellular matrix glycoprotein, and of high-sensitivity C-reactive protein (CRP) might serve as a marker of remodeling and progressive inflammation of the aorta and in myocardial diseases. This study aimed to clarify relationships between TNC and CRP in patients with AF.
View Article and Find Full Text PDFArticle Synopsis
- A study looked at a treatment called ablation for patients who had heart issues after a heart attack, specifically focusing on a fast heart rhythm called ventricular tachycardia (VT).
- 66 patients were treated, with some having their non-inducible VTs targeted using special heart monitoring devices, while others had only inducible VTs treated.
- The results showed that those who had the non-inducible VTs treated had a lower chance of having VT come back compared to the other group, showing this method could be helpful.
Article Synopsis
- The study explored whether antiarrhythmic drug (AAD) therapy impacts mortality rates after catheter ablation (CA) in patients with atrial fibrillation (AF), involving 3,624 patients over a mean follow-up of 6.7 years.
- Results showed that fewer deaths occurred in the AAD group (2.2%) compared to the no-AAD group (4.5%), suggesting a potential benefit from AAD use.
- While no significant difference in mortality was confirmed, there was a trend indicating that AAD therapy might be safe and not increase mortality risk after CA of AF.
Background: Postinfarction ventricular tachycardia (VT) generally involves myocardial fibers surrounded by scar. Calcification of scar tissue has been described, but the relationship between calcifications within endocardial scar and VTs is unclear. The purpose of this study was to assess the prevalence of myocardial calcifications as detected by cardiac computed tomography (CT) and the benefit for mapping and ablation focusing on nontolerated VTs.
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- This study explored the use of protamine to reverse the anticoagulation effects of heparin in patients undergoing catheter ablation for atrial fibrillation, filling a gap in existing research as no randomized controlled trials had been conducted previously.
- Researchers found that patients treated with protamine experienced significantly faster hemostasis (about 137 minutes quicker) and ambulation (around 164 minutes quicker) compared to the control group.
- Importantly, there were no significant differences in the rates of complications like major or minor vascular issues or thromboembolic events between the protamine and control groups, indicating a safer approach.
Introduction: Atrial Fibrillation (AF) is the most common cardiac arrhythmia, presenting a significant independent risk factor for stroke and thromboembolism. With the emergence of m-Health devices, the importance of automatic detection of AF in an off-clinic setting is growing. This study demonstrates the performance of a bimodal classifier for distinguishing AF from sinus rhythm (SR) that could be used for automated detection of AF episodes.
View Article and Find Full Text PDFBackground: The role of cryoballoon ablation (CBA) for antral pulmonary vein isolation (APVI) has not been well established in persistent atrial fibrillation (PerAF). Isolation of the left atrial posterior wall (BOX) after APVI has been suggested to improve the efficacy of radiofrequency catheter ablation (RFA) in PerAF.
Objective: The purpose of this study was to compare characteristics and clinical outcomes of APVI by CBA vs APVI + BOX by contact force-guided RFA (CF-RFA) in patients with PerAF.
Article Synopsis
- ATP-induced ventricular tachycardias (VTs) were found to be common in patients with implantable cardioverter-defibrillators (ICDs) who had previously experienced myocardial infarctions and were undergoing VT ablation procedures.
- In a study involving 162 patients, ATP-induced VTs were typically faster and less likely to be induced with invasive testing compared to spontaneous VTs, and they had fewer identifiable target sites.
- The study concluded that while ATP-induced VTs are prevalent and correlate with increased recurrence rates of VTs after ablation, they do not appear to directly cause recurrence.
Article Synopsis
- The study aims to assess how the timing between the P wave and local atrial electrograms can indicate complete conduction block during radiofrequency catheter ablation (RFA) for treating atrial flutter caused by cavo-tricuspid isthmus (CTI).
- It involved 125 patients, with measurements taken before and after achieving complete block, revealing distinct timing differences that can predict CTI block with high sensitivity and specificity.
- The findings suggest that monitoring these timing intervals is an effective and straightforward method for confirming complete block during the procedure.
Introduction: Although noninferiority of cryoballoon ablation (CBA) and radiofrequency catheter ablation for antral pulmonary vein isolation (APVI) has been reported in patients with paroxysmal atrial fibrillation (PAF), it is not clear whether contact force sensing (CF-RFA) and CBA with the second-generation catheter have similar procedural costs and long-term outcomes. The objective of this study is to compare the long-term efficacy and cost implications of CBA and CF-RFA in patients with PAF.
Methods And Results: A first APVI was performed in 146 consecutive patients (age: 63 ± 10 years, men: 95 [65%], left atrial diameter: 42 ± 6 mm) with PAF using CBA (71) or CF-RFA (75).
Background: Frequent premature ventricular complexes (PVCs) have been associated with increased mortality. However, the optimal approach to the risk stratification of these patients is unclear.
Objective: The purpose of this study was to prospectively assess the use of cardiac magnetic resonance imaging (MRI) and programmed ventricular stimulation to identify patients with PVCs undergoing radiofrequency ablation at risk for adverse long-term outcomes.
Article Synopsis
- Patients with a history of myocardial infarction who experience ventricular tachycardia (VT) recurrence after catheter ablation are at greater risk for death or heart transplantation, with risk varying based on the timing of the recurrence.* -
- In a study of 1412 patients, 42.8% had VT recurrence, usually within a few months after the procedure, and those who recurred within 30 days had a higher mortality risk compared to later recurrences.* -
- The risk of death or heart transplantation decreases over time post-ablation, with the greatest risk occurring soon after the recurrence and gradually lessening as time goes on.*