Atrial fibrillation nomenclature, definitions, and mechanisms: Position paper from the international Working Group of the Signal Summit.

The international Working Group of the Signal Summit is a consortium of experts in the field of cardiac electrophysiology dedicated to advancing knowledge on understanding and clinical application of signal recording and processing techniques. In 2023, the working group met in Reykjavik, Iceland, and laid the foundation for this manuscript. Atrial fibrillation (AF) is the most common arrhythmia in adults, with a rapidly increasing prevalence worldwide.

Starting fresh: a mixed method study of follower job satisfaction, trust, and views of their leader's behavior.

Introduction: The leadership literature has been dominated by the study of broad styles rather than the identification of specific key behaviors. To address this deficiency, a mixed method approach was utilized to explore how follower behavioral descriptions of their leaders would relate to potential outcomes of trust in that leader and job satisfaction.

Methods: Data were collected from 273 hospital direct reports of 44 managers.

Are Biasing Factors Idiosyncratic to Measures? A Comparison of Interpersonal Conflict, Organizational Constraints, and Workload.

Widespread concern has been raised about the possibility of potential biasing factors influencing the measurement of organizational variables and distorting inferences and conclusions reached about them. Recent research calls for a measure-centric approach in which every measure is independently evaluated to assess what factor(s) may uniquely bias it. This paper examines three popular stressor measures from this perspective.

Post-vaccination infection rates and modification of COVID-19 symptoms in vaccinated UK school-aged children and adolescents: A prospective longitudinal cohort study.

Background: We aimed to explore the effectiveness of one-dose BNT162b2 vaccination upon SARS-CoV-2 infection, its effect on COVID-19 presentation, and post-vaccination symptoms in children and adolescents (CA) in the UK during periods of Delta and Omicron variant predominance.

Methods: In this prospective longitudinal cohort study, we analysed data from 115,775 CA aged 12-17 years, proxy-reported through the Covid Symptom Study (CSS) smartphone application. We calculated post-vaccination infection risk after one dose of BNT162b2, and described the illness profile of CA with post-vaccination SARS-CoV-2 infection, compared to unvaccinated CA, and post-vaccination side-effects.

Adding fuel to the fire: The exacerbating effects of calling intensity on the relationship between emotionally disturbing work and employee health.

The burgeoning occupational callings literature has shown that feeling called to a job is associated with an array of positive job-, career-, and health-related outcomes. However, recent studies have begun to indicate that there may also be a "negative side" of callings. The present study builds on this emerging perspective to examine whether feeling called to a job makes helping professionals more vulnerable to the negative effects of acute stressors.

How Can Organizational Leaders Help? Examining the Effectiveness of Leaders' Support During a Crisis.

Organizational leaders can make a large, positive impact on their employees during crises. However, existing research demonstrates that social support is not always effective in helping employees cope with stress, and existing research has not fully identified features of support attempts that determine their effectiveness. Using mixed methods, the authors investigate the efficacy of organizational leaders' support efforts during a crisis.

Competitive Drivers of Atrial Fibrillation: The Interplay Between Focal Drivers and Multiwavelet Reentry.

Background: There is debate whether human atrial fibrillation is driven by focal drivers or multiwavelet reentry. We propose that the changing activation sequences surrounding a focal driver can at times self-sustain in the absence of that driver. Further, the relationship between focal drivers and surrounding chaotic activation is bidirectional; focal drivers can generate chaotic activation, which may affect the dynamics of focal drivers.

Cycle length statistics during human atrial fibrillation reveal refractory properties of the underlying substrate: a combined in silico and clinical test of concept study.

Aims: The treatment of atrial fibrillation beyond pulmonary vein isolation has remained an unsolved challenge. Targeting regions identified by different substrate mapping approaches for ablation resulted in ambiguous outcomes. With the effective refractory period being a fundamental prerequisite for the maintenance of fibrillatory conduction, this study aims at estimating the effective refractory period with clinically available measurements.

Helping may be Harming: unintended negative consequences of providing social support.

While social support is generally considered a helpful resource for employees, it can also serve as a job stressor. Unhelpful workplace social support (UWSS) is any action taken by a supervisor and/or colleague that the recipient believes was intended to benefit him or her but is perceived as unhelpful or harmful. Two studies, one qualitative and one quantitative, identified types of UWSS and demonstrated that unhelpful support can operate as a job stressor in relating to strains.

Extracellular Vesicles of Alzheimer's Disease Patients as a Biomarker for Disease Progression.

Alzheimer's disease (AD) is a progressive neurodegenerative brain pathology and the most common form of dementia. Evidence suggests that extracellular vesicles (EVs) containing cytokines and microRNA are involved in inflammation regulation. The current study aimed to explore a potential impact of AD patients' EVs on disease progression.

Information security climate and the assessment of information security risk among healthcare employees.

Since 2009, over 176 million patients in the United States have been adversely impacted by data breaches affecting Health Insurance Portability and Accountability Act-covered institutions. While the popular press often attributes data breaches to external hackers, most breaches are the result of employee carelessness and/or failure to comply with information security policies and procedures. To change employee behavior, we borrow from the organizational climate literature and introduce the Information Security Climate Index, developed and validated using two pilot samples.

Activation Mapping With Integration of Vector and Velocity Information Improves the Ability to Identify the Mechanism and Location of Complex Scar-Related Atrial Tachycardias.

Background: Activation mapping of scar-related atrial tachycardias (ATs) can be difficult to interpret because of inaccurate time annotation of complex electrograms and passive diastolic activity. We examined whether integration of a vector map can help to describe patterns of propagation to better explain the mechanism and location of ATs.

Methods: The investigational mapping algorithm calculates vectors and applies physiological constraints of electrical excitation in human atrial tissue to determine the arrhythmia source and circuit.

Digging deeper into the shared variance among safety-related climates: the need for a general safety climate measure.

We combined three independent streams of workplace climate research, safety, violence prevention, and civility, to devise a general safety climate scale that explicitly addressed a variety of risks. A confirmatory factor analysis suggested that a higher-order factor may be responsible for the similarity in relationships across these safety-related climate measures with exposure to organizational hazards and resulting employee outcomes. As a result, a concise 10-item measure was developed and validated to assess a possible general safety climate factor.

Being Called to Safety: Occupational Callings and Safety Climate in the Emergency Medical Services.

Objective: The aim of this study was to investigate the importance of safety climate in the Emergency Medical Services (EMS) and to assess occupational callings as a boundary condition for the effect of safety climate on safety behaviors.

Methods: EMS professionals (n = 132) participated in a three-wave survey study. Hierarchical linear regressions were conducted to test the moderating effects of occupational callings.

Grin and Bear It?: Employees' Use of Surface Acting During Co-worker Conflict.

Using survey data from 459 employed individuals, the conditional indirect effects of three types of interpersonal conflict at work on strains and performance through surface acting were tested. Results indicated that task, relationship and non-task organizational conflict were positively related to depressive and physical symptoms and negatively related to performance. Task conflict had a significantly weaker association with employee outcomes than either relationship or non-task organizational conflict.

A test of safety, violence prevention, and civility climate domain-specific relationships with relevant workplace hazards.

Background: Safety climate, violence prevention climate, and civility climate were independently developed and linked to domain-specific workplace hazards, although all three were designed to promote the physical and psychological safety of workers.

Purpose: To test domain specificity between conceptually related workplace climates and relevant workplace hazards.

Methods: Data were collected from 368 persons employed in various industries and descriptive statistics were calculated for all study variables.

Prospective, Tissue-Specific Optimization of Ablation for Multiwavelet Reentry: Predicting the Required Amount, Location, and Configuration of Lesions.

Background: Treatment of multiwavelet reentry (MWR) remains difficult. We previously developed a metric, the fibrillogenicity index, to assess the propensity of homogeneous, 2-dimensional tissues to support MWR. In this study, we demonstrate a method by which fibrillogenicity index can be generalized to heterogeneous tissues and validate an algorithm for prospective, tissue-specific optimization of ablation to reduce MWR burden.

Political skill: A proactive inhibitor of workplace aggression exposure and an active buffer of the aggression-strain relationship.

In the current study we examined the role of 4 dimensions of political skill (social astuteness, interpersonal influence, networking ability, and apparent sincerity) in predicting subsequent workplace aggression exposure based on the proactive coping framework. Further, we investigated their buffering effects on the negative outcomes of experienced workplace aggression based on the transactional stress model. Data were collected from nurses at 3 time points: before graduation (Time 1, n = 346), approximately 6 months after graduation (Time 2, n = 214), and approximately 12 months after graduation (Time 3, n = 161).

Prospectively quantifying the propensity for atrial fibrillation: a mechanistic formulation.

The goal of this study was to determine quantitative relationships between electrophysiologic parameters and the propensity of cardiac tissue to undergo atrial fibrillation. We used a computational model to simulate episodes of fibrillation, which we then characterized in terms of both their duration and the population dynamics of the electrical waves which drove them. Monte Carlo sampling revealed that episode durations followed an exponential decay distribution and wave population sizes followed a normal distribution.

Structural defects lead to dynamic entrapment in cardiac electrophysiology.

Biological networks are typically comprised of many parts whose interactions are governed by nonlinear dynamics. This potentially imbues them with the ability to support multiple attractors, and therefore to exhibit correspondingly distinct patterns of behavior. In particular, multiple attractors have been demonstrated for the electrical activity of the diseased heart in situations where cardioversion is able to convert a reentrant arrhythmia to a stable normal rhythm.

Mapping multi-wavelet reentry without isochrones: an electrogram-guided approach to define substrate distribution.

Aims: A key mechanism responsible for atrial fibrillation is multi-wavelet reentry (MWR). We have previously demonstrated that ablation in regions of increased circuit density reduces the duration of, and decreases the inducibility of MWR. In this study, we demonstrate a method for identifying local circuit density using electrogram frequency and validated its effectiveness for map-guided ablation in a computer model of MWR.