Recurrence after successful catheter ablation for ventricular arrhythmia from the aortic root.

OBJECTIVE: The mechanism underlying recurrence after successful ablation of ventricular arrhythmias (VAs) was unclear. Spectrum analysis can help to identify near-field activation. The purpose of this study was to quantify the changes of near-field activation in response to ablation at the VAs origin in the aortic root (AR-VAs) and to assess its relationship with late ablation outcome. METHODS AND RESULTS: Patients who underwent acutely successful ablation for AR-VAs were analysed. Ventricular electrograms acquired before and after ablation at VAs origin were subjected to spectrum analysis. The area under the curve of the high frequency component (HFC, 50-200 Hz) and the low frequency component (LFC, 0-50 Hz) was measured. The proportion of HFC to the frequency spectrum of 0-200 Hz was defined as the HFC ratio (HFCR). The reduction of HFC and HFCR in response to ablation was defined as HFC pre-post and HFCR pre-post, respectively. Documentation of VAs with the same morphology after an acute successful procedure was defined as recurrence. Fifty-six patients were analysed, and VAs recurred in 17 patients. HFCR pre-post, HFC pre-post, and HFC pre-ablation were significantly higher in patients without recurrence. And HFCR pre-post has the highest predictive value (area under the receiver-operating characteristic curve: 0.975). A HFCR pre-post of 1.0% differentiated two groups (sensitivity = 84.6%, specificity = 100%). Higher HFCR pre-post was correlated with shorter VAs termination time (correlation coefficient = -0.399, p = .009). CONCLUSIONS: HFCR pre-post can quantify the near-field activation change during ablation. Incomplete destruction to the VAs foci could underlie recurrence after successful ablation.

Pouched mitral isthmus is associated with incomplete linear block in atrial fibrillation patients with mechanical mitral valve replacement.

BACKGROUND: Previous studies have described the impact of mitral isthmus (MI) anatomy on the likelihood of achieving MI linear block in patients with native mitral valves (NMV) who underwent atrial fibrillation (AF) ablation. However, none have investigated that issue in AF patients with mechanical mitral valve replacements (MMVR). METHODS AND RESULTS: Twenty-nine consecutive patients who developed symptomatic persistent AF post-MMVR and referred for ablation were enrolled. Twenty-nine patients with NMV who underwent ablation of persistent AF during the same period were matched. With preprocedural cardiac computed tomographic imaging, MI anatomical features of all the participants were analyzed. Pouched MI was observed in 19 (65.5%) MMVR patients versus to 6 (20.7%) controls (P = 0.001). Bidirectional linear block across MI was achieved in 21 (72.4%) MMVR patients and 22 (75.9%) in the controls (P = 0.764). In the multivariable analysis, pouched MI was an independent predictor of incomplete MI block. CONCLUSIONS: Pouched MI accounts for the majority of AF patients with MMVR and may be associated with incomplete bidirectional linear block of MI.

Plasma galectin-3 predicts clinical outcomes after catheter ablation in persistent atrial fibrillation patients without structural heart disease.

AIMS: This study sought to explore the relationship between plasma galectin-3 (Gal-3) and persistent atrial fibrillation (PsAF), and investigate whether Gal-3 predicts clinical outcomes in patients with PsAF undergoing catheter ablation. METHODS: Fifty consecutive PsAF patients without coexisting structural heart disease undergoing first-time catheter ablation and 46 healthy controls were included. Blood samples were collected on admission for analysis of plasma Gal-3. Pre-ablation clinical and laboratory data were also recorded. Persistent atrial fibrillations patients were followed after ablation and AF recurrence was defined as episodes of AF or atrial tachycardia lasting >30 s after the blanking period. RESULTS: Plasma Gal-3 concentrations were higher in PsAF patients than in healthy controls (P < 0.001). In PsAF group, those with AF recurrence had higher plasma Gal-3 than did those without recurrence (P = 0.007). Both Gal-3 (hazard ratio 1.28, P = 0.006) and left atrial diameter (LAD) (hazard ratio 1.1, P = 0.025) were independent predictors of AF recurrence after ablation. Moreover, adding Gal-3 to LAD had an incremental predictive value for ablation outcomes (global χ(2) of LAD alone: 8.2; LAD and Gal-3 concentrations: 15.7; P = 0.006). CONCLUSION: Plasma Gal-3 concentrations are elevated in PsAF patients without structural heart disease and independently predict AF recurrence after ablation. Plasma Gal-3 concentration may be helpful in identifying appropriate candidates for AF ablation.

Adaptive Safety Coding in the Prefrontal Cortex.

Pivotal to self-preservation is the ability to identify when we are safe and when we are in danger. Previous studies have focused on safety estimations based on the features of external threats and do not consider how the brain integrates other key factors, including estimates about our ability to protect ourselves. Here we examine the neural systems underlying the online dynamic encoding of safety. The current preregistered study used two novel tasks to test four facets of safety estimation: Safety Prediction, Meta-representation, Recognition, and Value Updating. We experimentally manipulated safety estimation changing both levels of external threats and self-protection. Data were collected in two independent samples (behavioral N=100; fMRI N=30). We found consistent evidence of subjective changes in the sensitivity to safety conferred through protection. Neural responses in the ventromedial prefrontal cortex (vmPFC) tracked increases in safety during all safety estimation facets, with specific tuning to protection. Further, informational connectivity analyses revealed distinct hubs of safety coding in the posterior and anterior vmPFC for external threats and protection, respectively. These findings reveal a central role of the vmPFC for coding safety.

Latent motives guide structure learning during adaptive social choice.

Predicting the behaviour of others is an essential part of social cognition. Despite its ubiquity, social prediction poses a poorly understood generalization problem: we cannot assume that others will repeat past behaviour in new settings or that their future actions are entirely unrelated to the past. We demonstrate that humans solve this challenge using a structure learning mechanism that uncovers other people's latent, unobservable motives, such as greed and risk aversion. In four studies, participants (N = 501) predicted other players' decisions across four economic games, each with different social tensions (for example, Prisoner's Dilemma and Stag Hunt). Participants achieved accurate social prediction by learning the stable motivational structure underlying a player's changing actions across games. This motive-based abstraction enabled participants to attend to information diagnostic of the player's next move and disregard irrelevant contextual cues. Participants who successfully learned another's motives were more strategic in a subsequent competitive interaction with that player in entirely new contexts, reflecting that social structure learning supports adaptive social behaviour.

HATCH score in the prediction of new-onset atrial fibrillation after catheter ablation of typical atrial flutter.

BACKGROUND: New-onset atrial fibrillation (AF) is not uncommon after ablation of typical atrial flutter (AFL); however, limited data are available for a risk prediction model for the future occurrence of AF in patients with typical AFL undergoing successful catheter ablation. OBJECTIVE: This study aimed to determine whether the HATCH score (which is based on hypertension, age ≥75 years, transient ischemic attack or stroke, chronic obstructive pulmonary disease, and heart failure) is useful for risk prediction of subsequent AF after ablation of typical AFL. METHODS: A total of 216 consecutive patients presenting with typical AFL and no history of AF who underwent successful catheter ablation were enrolled in the study. The clinical endpoint was occurrence of new-onset AF during follow-up after ablation. RESULTS: During a follow-up period of 29.1 ± 18.3 months, 85 patients (39%) experienced at least 1 episode of AF. Multivariate Cox regression analysis demonstrated that the HATCH score (hazard ratio 1.784; 95% confidence interval 1.352-2.324; P < .001) and left atrial diameter (hazard ratio 1.270; 95% confidence interval 1.115-1.426; P < .001) were independently associated with new-onset AF after typical AFL ablation. The area under the receiver operator characteristic curve based on the HATCH score for prediction of new-onset AF was 0.743. The HATCH score could be used to stratify the patients into 2 groups with different incidences of new-onset AF (69% vs 27%, P < .001) at a cutoff value of 2. CONCLUSIONS: The HATCH score is a useful predictor of new-onset AF after typical AFL ablation.