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Introduction: There is a lack of studies in the literature directly investigating the relationship between atrial tachycardia (AT) and left atrial (LA)/left atrial appendage (LAA) thrombus, and current guidelines do not provide strong recommendations regarding the use of transesophageal echocardiography (TEE) before AT catheter ablation. This study aims to elucidate the relationship between AT and the presence of LA/LAA thrombus and contribute to the literature on the use of TEE before AT catheter ablation., Methods: This single-center retrospective observational study screened patients who underwent TEE between February 10, 2019, and February 10, 2023. Patients were assigned to the AT patient and control groups. TEE was conducted to exclude thrombus in the AT ablation group. The control group included patients who underwent TEE for interatrial septum evaluation and had LA imaging during TEE but did not have atrial arrhythmia. To mitigate bias between the AT patient group and the control group, they were randomized 1:1 using propensity-score matching (PSM). Following randomization, each group consisted of 49 patients., Results: All analyses were conducted after PSM. There were no statistically significant differences between the AT patient and control groups in terms of baseline clinical characteristics and echocardiographic features. Additionally, no significant differences were found between the blood viscosities calculated at low and high shear rates in both groups. The study revealed a significant difference between the two groups in the presence of LA spontaneous echo contrast (SEC) (24.5% in AT group vs 0% in Control group, p = .001), but not in the presence of thrombi (8.2% in AT group vs 0% in Control group, p = .117)., Conclusion: Compared to the control group, the presence of SEC was significantly higher in the AT patient group. The increased frequency of SEC in AT patients suggests the hypothesis that AT may contribute to LA stasis. The routine use of TEE before AT catheter ablation remains controversial, despite the presence of LA thrombus and SEC in the AT patient group. The clinical assessment of thrombus presence before the procedure must be conducted on a patient-specific basis., (© 2024 Wiley Periodicals LLC.)

Background: Stereotactic body radioablation therapy (SBRT) has recently been introduced with the ability to provide ablative energy noninvasively to arrhythmogenic substrate while reducing damage to normal cardiac tissue nearby and minimizing patients' procedural risk. There is still debate regarding whether SBRT has a predominant effect in the early or late period after the procedure. We sought to assess the time course of SBRT's efficacy as well as the value of using a blanking period following a SBRT session., Methods: Eight patients (mean age 58 ± 14 years) underwent eight SBRT sessions for refractory ventricular tachycardia (VT). SBRT was given using a linear accelerator device with a total dose of 25 Gy to the targeted area., Results: During a median follow-up of 8 months, all patients demonstrated VT recurrences; however, implantable cardioverter-defibrillator (ICD) and anti-tachycardia pacing therapies were significantly reduced with SBRT (8.46 to 0.83/per month, p = 0.047; 18.50 to 3.29/per month, p = 0.036, respectively). While analyzing the temporal SBRT outcomes, the 2 weeks to 3 months period demonstrated the most favorable outcomes. After 6 months, one patient was ICD therapy-free and the remaining patients demonstrated VT episodes., Conclusions: Our findings showed that the SBRT was associated with a marked reduction in the burden of VT and ICD interventions especially during first 3 months. Although SBRT does not seem to succeed complete termination of VT in long-term period, our findings support the strategy that SBRT can be utilized for immediate antiarrhythmic palliation in critically ill patients with otherwise untreatable refractory VT and electrical storm., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: We aimed to investigate the predictive role of systemic immune inflammation index (SII) on atrial fibrillation (AF) recurrence following cryoballoon-based AF ablation. Materials & methods: A total of 370 consecutive patients with symptomatic AF who underwent cryoablation were enrolled. The patients were divided into two groups according to recurrence development. Results: During the follow-up period of 25.0 ± 6.7 months, recurrence was observed in 77 patients (20.8%). Receiver operating characteristic analysis demonstrated that using a cutoff level of 532, SII had a sensitivity of 71% and specificity of 68%. In the multivariate Cox model, high SII was a significant predictor of the recurrence. Conclusion: This study showed that higher SII level is an independent predictor of AF recurrence.

Catheter ablation of the slow pathway is the recommended treatment for atrioventricular nodal reentrant tachycardia (AVNRT) in children. Both radiofrequency ablation (RF) and cryoablation (CA) have been used for this purpose. In this report, we describe our experience during the transition period from RF to CA for the treatment of pediatric AVNRT. Between January 2012 and August 2021, a retrospective evaluation was conducted of the clinical features, procedural outcomes, and follow-ups of pediatric AVNRT patients who underwent catheter ablation at a pediatric electrophysiology center. The catheter ablation outcomes of 89 pediatric AVNRT patients were evaluated: 29 patients were ablated using RF (RF group) and 60 patients were ablated using CA (CA group). No significant difference was found between the groups in terms of gender, age, weight, and success and recurrence rates. The procedure duration and total lesion numbers were statistically significantly lower in the RF group compared with the CA group (86.67 ± 45.8 and 156.1 ± 37.7 min; p = 0.01, 4 [3-6] and p < 0.01, 8 [7-9] lesions, respectively). Catheter ablation was successful in all patients. There were no permanent complete atrioventricular blocks in both groups. A total of six patients (6.8%) developed recurrences. The cryoablation of pediatric AVNRT is a safe and effective procedure with comparable acute and mid-term follow-up success rates compared with RF, even during a period of transition from RF to CA., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Catheter ablation is a popular therapy of atrial fibrillation (AF). Gamma-glutamyl transferase (GGT) is known as a marker of oxidative stress. The objective of this study was to ascertain the relationship between levels of GGT and recurrence of AF after catheter ablation., Methods: A total of 102 paroxysmal AF patients who underwent cryoballoon catheter ablation were enrolled. Serum samples were obtained to evaluate GGT levels before catheter ablation. Cox regression analysis was used to estimate the predictors of AF recurrence., Results: Mean age of the cohort was 49.9 ± 11.7 and 63% of the patients were male. After a mean follow-up of 20 months, 19 (23%) patients had AF recurrences. The baseline GGT levels were significantly higher in patients who had AF recurrence [27 U/L (17-36) vs 18 U/L (13-22), P = 0.002]. The optimal cut-off value of GGT to predict AF recurrence was 23.5 U/L according to receiver operating characteristic curve analysis (area under the curve 0.72, P = 0.002). In the multivariable Cox regression analysis, baseline GGT > 23.5 was the only independent predictor of AF recurrence (hazard ratio (HR) 4.47, 95% confidence interval [1.66-12.09], P = 0.003)., Conclusions: Our results indicate that elevated GGT is associated with AF recurrence. A simple measurement of GGT may help us to identify high-risk patients undergoing catheter ablation for AF.

Purpose: The intrinsic atrial vulnerability is proposed as one of the mechanisms of paroxysmal atrial fibrillation (PAF) in Wolff-Parkinson-White (WPW) syndrome. In this study, we examined the early changes in atrial refractoriness and intra- and inter-atrial conduction times after radiofrequency (RF) catheter ablation of accessory pathway (AP)., Methods: Twenty-four consecutive patients with WPW syndrome and documented AV reciprocating tachycardia but without history of PAF (fourteen male, mean age 39 +/- 9.5 years) and 27 control subjects (six female, mean age 51.4 +/- 10.1 years) with AV nodal reentrant tachycardia (AVNRT) who underwent ablation of the slow AV nodal pathways were enrolled into the study. Regional atrial effective refractory periods (AERPs), AERP dispersion, and intra- and inter-atrial conduction times were obtained before and 30 min after ablation and were compared between two groups. In the study group, patients with and without inducible AF were also compared regarding these parameters., Results: In the study group, AERPs in higher right atrium and right posterolateral atrium were significantly increased, and AERP dispersion, intra-atrial, and inter-atrial conduction times were significantly decreased after ablation; AERP in distal coronary sinus was unchanged. In control group, no significant difference was observed in these parameters. Inducibility of AF was significantly reduced following ablation of AP in the study group (from seven to zero of 24 patients, p = 0.016). Comparison between patients with (n = 7) and without (n = 17) AF revealed that left atrium diameter was larger, AERPs in the right posterolateral atrium before and after ablation, and ERP of AP were shorter in AF group., Conclusion: In WPW syndrome patients, RF catheter ablation of AP results in an 'immediate' decrease in atrial vulnerability. Since inducibility of AF becomes more difficult in this less vulnerable atrium, the AP itself may play an important role in the development of AF.