A gray zone: Role of transesophageal echocardiography before atrial tachycardia catheter ablation.

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.

Telltale termination of an A-on-V tachycardia with two blocked atrial activations: What is the mechanism?

The termination of tachycardia may provide important clues toward the mechanism of the tachycardia and that close vigilance may clinch the diagnosis before proceeding to other pacing maneuvers.

Unusual response to His-refractory atrial premature complex: What is the mechanism?

A 32-year-old woman underwent radiofrequency catheter ablation of narrow QRS tachycardia that was terminated with intravenous adenosine.

The other side of the medallion in heart failure: Reverse metabolic syndrome.

BACKGROUND AND AIMS: Lower levels of cardiovascular risk factors are associated with an increase in mortality in H.F. To explain this paradox, the term reverse metabolic syndrome (RMetS) has recently been proposed. We suggest defining these patients with lower levels of three risk factors can be combined under the heading "RMetS." We aimed to investigate the effect of MetS and RMetS on hemodynamic parameters and prognosis in patients with H.F. and reduced ejection fraction (HFrEF). METHODS AND RESULTS: We included 304 patients who were performed right heart catheterization and followed up for a median of 16 (0-48) months. We first grouped patients according to the presence of MetS or not, then we added the RMetS category and stratified patients into three groups as MetS, RMetS, and metabolic healthy. Compared with not MetS group, Pulmonary arterial pressures and VO2 were higher in MetS group. In the second step, LVEF, CI, VO2I, O2 delivery, and LVSWI were lowest in RMetS, pulmonary artery pressures were higher in MetS group. In multivariate Cox regression analysis, being in RMetS group was associated with 2.4 times and 1.8 times increased risk for composite end point (CEP) and all-cause mortality, respectively. In Kaplan Meier analysis, RMetS had the highest all-cause mortality and CEP. CONCLUSIONS: We determined that RMetS patients had the worst prognosis with unfavorable hemodynamic profile. Hence, a better understanding of the pathophysiology of RMetS may help refine the treatment targets of CV risk factors, may yield new interventions targeting catabolic syndrome.

His bundle pacing using a simple stylet and a standard active fixation electrode.

Conventionally, His bundle pacing (HBP) is achieved using specially designed pacing leads and delivery sheaths. This paper describes the feasibility of permanent HBP with a pre-shaped simple stylet and a standard active-fixation electrode, through axillary vein access, without using dedicated delivery tools. This method may be a feasible and safe alternative to the only commercially available system.

Free Epoxide Content Mediates Encapsulated Cell Viability and Activity through Protein Interactions in a Thermoresponsive, In Situ Forming Hydrogel.

The development of synthetic and well-defined extracellular matrices that are free of xenogeneic components and are capable of inducing desired cellular responses holds great potential for use in vitro as 3D cell culture environments and in vivo as scaffolds for tissue regeneration. In this study, the impact of free and partially occupied epoxide groups on the viability, activity, and behavior of rat fibroblasts encapsulated in thermoresponsive hydrogels based on poly(N-isopropylacrylamide) (pNiPAAm) was investigated. While fibroblasts encapsulated in neat pNiPAAm remained rounded and showed significant toxicity by 5 days, those encapsulated in the epoxide-modified thermogels demonstrated not only high viability but also an ability to proliferate, attach, produce extracellular matrix (ECM) components, and cluster. The results demonstrated that the presence of free epoxide groups led to the local conjugation of available proteins to produce a modified structure in situ, which supported cell viability, activity, and cluster formation within the hydrogel.

The short-term impact of the catheter ablation on noninvasive autonomic nervous system parameters in patients with paroxysmal atrial fibrillation.

BACKGROUND: The autonomic nervous system (ANS) is a potentially potent modulator of the initiation and perpetuation of atrial fibrillation (AF), whereas the presence of AF can activate and alter the ANS. The catheter ablation of AF (AFCA) may cause the cardiac ANS dysfunction, whereas restoration of sinus rhythm or sympathovagal imbalance by AFCA can reverse this process. Our principal goal was to investigate the short-term effect of AFCA on ANS functions evaluated by noninvasive chronotropic (CI), resting heart rate (RHR), and heart rate recovery (HRR) indices. METHOD: A total of 45 patients were enrolled with symptomatic, drug refractory paroxysmal AF undergoing first cryoballoon (CB) pulmonary vein antrum isolation (PVAI) with one 28-mm CB using single 3-minute freeze techniques without bonus applications. All patients underwent symptom-limited exercise treadmill testing to evaluate noninvasive parameters of ANS before PVAI. For those patients who remained in sinus rhythm, an additional exercise test was repeated after 1 and 3 months after discharge. RESULTS: The autonomic CI and RHR/HRR indices were impaired after PVAI and persisted post-PVAI 3 months. However, these parameters were not different in patients with and without recurrence. CONCLUSION: This study demonstrated that the successful AFCA might concurrently impair the ANS parameters. The autonomic imbalance between the sympathetic and parasympathetic activity after AFCA could either become antiarrhythmic and/or proarrhythmic based on which of the two components was going to prevail after successful AFCA. The impaired ANS balance after PVAI might also be another hypothetical mechanism for AF recurrence particularly in the absence of PV reconnection.

Predictors of Impaired Reperfusion after Percutaneous Coronary Intervention in Patients with In-Hospital Acute Stent Thrombosis: A Retrospective Analyses of 5 Years of Data.

BACKGROUND: Acute stent thrombosis (STh) is a rare complication of percutaneous coronary intervention (PCI) and is associated with a high-risk of reperfusion failure. However, data focusing on risk factors of reperfusion failure in patients undergoing repeat PCI for treatment of STh remains inadequate. METHODS: A total of 8815 patients who underwent PCI with stent implantation from January 2009 to December 2013 were retrospectively reviewed. Among those cases, patients that presented with acute STh and underwent a repeat PCI for acute STh were identified. RESULTS: There were 108 patients who underwent repeat PCI for the treatment of in-hospital acute STh that were retrospectively analyzed. Of these study subjects, 21 (25%) had thrombolysis in myocardial infarction (TIMI) flow < 3 after repeat PCI. The median value of pain-to-balloon time was 40 minutes in the TIMI < 3 group, 35 minutes in the TIMI = 3 group (p < 0.001), and the first PCI-to-stent thrombosis time was also longer in the TIMI < 3 group (10 hours vs. 2.5 hours, p = 0.001). When patients were evaluated according to PCI time, the percentage of patients with TIMI < 3 was significantly higher in the night period compared to the daytime period (46.4% vs. 17.5 %, p = 0.002). In the multivariable logistic regression analysis, stent length [odds ratio (OR) = 1.18, 95% confidence interval (CI) 1.008-1.38] and pain-to- balloon time (OR = 1.28, 95% CI, 1.06-1.54) were the only independent predictors of failed reperfusion. CONCLUSIONS: Baseline stent length and pain-to-balloon time were associated with reperfusion failure in PCI for STh. Moreover, TIMI flow grade showed a circadian variation.