Background: The incidence of ventricular fibrillation (VF) out-of-hospital cardiac arrest (OHCA) treated by first responders has declined over the past decade. Since VF OHCA occurs primarily in the setting of severe coronary artery disease, primary and secondary prevention strategies may in part account for the decline. However, such strategies may not have a similar impact on non-ischemic arrest. Methods: All Rochester Minnesota residents who presented with a VF OHCA from 1991 to 2004, treated by emergency medical services (EMS), were included in the study. Incidence rates were calculated based on the population for Rochester during the time period. Changes over time were tested using Poisson regression models. The significance of the trends was estimated according to the Mantel-Haenszel test for association, and two-tailed p-values reported. Results: The overall incidence of EMS-treated VF OHCA in Rochester during the study period was 10.6 per 100,000 (95% CI 9.1-11.8). The incidence decreased significantly (p < 0.001) over the study period [1991-1994: 18.2/100,000 (95% CI 13.4-21.9); 1995-1999: 11.8/100,000 (95% CI 10.4-17.9); 2000-2004: 8.7/100,000 (95% CI 6.0-13.0)]. The incidence of VF OHCA with ischemic heart disease also declined [1991-1994: 13.4/100,000 (95% CI 8.9-16.9); 1995-1999: 11.1/100,000 (95% CI 8.2-15.9); 2000-2004: 5.5/100,000 (95% CI 3.8-8.2), p < 0.001]. In contrast, the incidence VF OHCA with non-ischemic heart disease increased [1991-1994: 2.1/100,000 (95% CI 1.13-3.1); 1995-1999: 2.3/100,000 (95% CI 1.9-3.7); 2000-2004: 2.9/100,000 (95% CI 2.0-3.4), p < 0.001]. Conclusion: The incidence of VF OHCA is declining. The decline is attributable to the reduction of VF cardiac arrest with ischemic heart disease; suggesting an impact of treatment strategies targeted at coronary artery disease. The relative increasing incidence of non-ischemic VF OHCA suggests that more efforts are required to minimize mortality in this cohort population.

La fibrillation auriculaire (FA) est la plus fréquente des arythmies cardiaques. La FA est associée à un risque accru d’accident vasculaire cérébral, d’insuffisance cardiaque et de mortalité, constituant un problème de santé publique majeur. L’avènement de nouvelles technologies permettant une surveillance électrocardiographique a démontré une haute prévalence de FA subclinique ou silencieuse chez les patients âgés à haut risque. Récemment, plusieurs efforts et essais thérapeutiques ont été dirigés vers une identification et un traitement plus précoces de la FA chez ces patients. L’anticoagulation orale a bien prouvé son efficacité dans la prévention thromboembolique chez les patients qui présentent un haut risque thromboembolique, mais au prix d’une augmentation significative des événements hémorragiques, un risque qui s’élève régulièrement chez les patients âgés et avec une comorbidité importante. Au cours des dernières années, des nouvelles alternatives non-pharmacologiques dans la prévention thromboembolique ont été développées. La fermeture percutanée de l’auricule gauche, site de formation de la majorité (~90%) des thrombus, est progressivement devenue une alternative valable à l’anticoagulation chez des patients avec FA non valvulaire à haute risque hémorragique. L’expérience des opérateurs et les innovations technologiques ont permis une amélioration remarquable des résultats en ce qui concerne la sécurité et l’efficacité. Cependant, quelques questions restent sans réponse. Les préoccupations les plus débattues suite à la fermeture de l’auricule gauche sont la prise en charge de l’anticoagulation postprocédure et la prévention/gestion de la thrombose de dispositif. Les objectifs de ce travail de recherche sont : (i) évaluer la charge arythmique silencieuse chez des patients à haut risque à l’aide de l’utilisation de nouveaux systèmes d’enregistrement électrocardiographique prolongé, et (ii) analyser l'impact hémodynamique et thrombogénique de la fermeture percutanée de l'auricule gauche avec les dispositifs actuels et émergents. / Atrial fibrillation (AF) is the most common cardiac arrhythmia. AF is associated with an increased risk of stroke, heart failure and mortality, posing a major public health problem. The advent of new technologies for continuous electrocardiographic monitoring has demonstrated a high incidence of subclinical or silent AF in elderly high-risk patients. Recently, several therapeutic efforts and studies have been directed towards earlier identification and treatment of AF in these patients. Oral anticoagulation has proven to be effective in preventing thromboembolism in patients at high thromboembolic risk, albeit at the expense of a significant increase in hemorrhagic events; a risk that increases steadily in elderly patients with high comorbidity burden. In recent years, novel non-pharmacological alternatives have been developed for thromboembolic prevention. Percutaneous left atrial appendage (LAA) closure, site of origin of the vast majority (~ 90%) of thrombi, has progressively become a valid alternative to anticoagulation in patients with non-valvular AF at high bleeding risk. Increasing operators' experience and technological innovations have led to remarkable improvements in the safety and efficacy of the procedure. However, some issues remain unanswered or controversial. Two of the most debated concerns are post-procedural antithrombotic management and device-related thrombosis (DRT) following LAA closure. The aims of the present research study are: (i) to evaluate the silent arrhythmic burden in high-risk patients using novel prolonged continuous electrocardiographic monitoring systems, and (ii) to assess the hemodynamic and thrombogenic impact of percutaneous LAA closure using current and emerging devices.

No description available.

There are in excess of one million people across the UK people living with atrial fibrillation (AF), a long term condition that can lead to stroke and other complications, costing the NHS over £2,200 million per year. However little is known about the experience of living with AF and what patients' perceptions are of the support they receive from health professionals. In order to ensure that patients have the best possible experience of care, healthcare professionals need to have an understanding of how patients view their condition and the type of support they would like to receive from the professionals involved in their care. Although there has been a significant amount of work investigating social support for people with health conditions, there has been little work exploring support provided by healthcare professionals, defined in this study as professional support. This study aimed to investigate and assess the professional support needs of people with AF to develop knowledge and understanding in this field. A theoretical framework for professional support was developed based on the tri-dimensional model of social support and was used to direct the research. Using an exploratory sequential design, a two phase mixed methods study was undertaken. Initially, qualitative interviews were undertaken with patients recruited from outpatient arrhythmia clinics at one National Health Service (NHS) hospital and identified from the perspective of the patient how, when and where healthcare professionals did/did not provide support. Key components of emotional, informational and tangible professional support were identified from thematic analysis of the interview data and used to inform the development of a quantitative questionnaire. Physical activity, exercise and the impact of AF on activity levels were identified by participants as important and so were also included. The quantitative online questionnaire was completed by patient members of the Atrial Fibrillation Association (AFA). To examine relationships between variables, statistical analyses were performed using Fisher's exact test and indicated that people with AF had a range of emotional, informational and tangible professional support needs. Different subgroups of people with AF had different professional support needs: People with more severe symptoms needed more emotional support as well as more tangible support and people with paroxysmal AF needed more informational support. People undergoing ablation as treatment for their AF had specific informational and emotional needs for support. AF played a significant part in the lives of people with AF by modifying activities of daily living and shaping physical activity behaviour and choice of activities. People with AF therefore needed professional support in maintaining and/or increasing their levels of activity. Considering the specificity of professional support, GPs, cardiologists and arrhythmia nurse specialists were identified as most supportive, with GPs and cardiologists also considered as the least helpful at providing support, indicating a variation in professional support. The findings from this study contribute to the limited body of knowledge describing the experience of living with AF and provide healthcare professionals with a unique understanding of how best to provide professional support. The tri-dimensional model provides detailed knowledge of the components of informational, emotional and tangible support that people with AF would like to receive from the healthcare professionals involved in their care. The findings indicate there are differing support needs for different subsets of people with AF demonstrating a need for individualised professional support. The theoretical framework for professional support used in this study provides a model that could be used in future research studies to identify the types of professional support required by patients and to identify subgroups of patients who may require additional professional support. By accurately identifying the needs of patients, this will ensure that healthcare professionals are able to deliver effective patient centred services, leading to an improved patient experience and the delivery of high quality patient care.

The aim of this thesis was to describe and explore how the partner relationship of patient–partner dyads isaffected following cardiac disease and, in particular, atrial fibrillation (AF) in one of the spouses. The thesis is based on four individual studies with different designs: descriptive (I), explorative (II, IV), and cross-sectional (III). Applied methods comprised a systematic review (I) and qualitative (II, IV) and quantitative methods (III). Participants in the studies were couples in which one of the spouses was afflicted with AF. Coherent with a systemic perspective, the research focused on the dyad as the unit of analysis. To identify and describe the current research position and knowledge base, the data for the systematic review were analyzed using an integrative approach. To explore couples’ main concern, interview data (n=12 couples) in study II were analyzed using classical grounded theory. Associations between patients and partners (n=91 couples) where analyzed through the Actor–Partner Interdependence Model using structural equation modelling (III). To explore couples’ illness beliefs, interview data (n=9 couples) in study IV were analyzed using Gadamerian hermeneutics. Study I revealed five themes of how the partner relationship is affected following cardiac disease: overprotection, communication deficiency, sexual concerns, changes in domestic roles, and adjustment to illness. Study II showed that couples living with AF experienced uncertainty as the common main concern, rooted in causation of AF and apprehension about AF episodes. The theory of Managing Uncertainty revealed the strategies of explicit sharing (mutual collaboration and finding resemblance) and implicit sharing (keeping distance and tacit understanding). Patients and spouses showed significant differences in terms of self-reported physical and mental health where patients rated themselves lower than spouses did (III). Several actor effects were identified, suggesting that emotional distress affects and is associated with perceived health. Patient partner effects and spouse partner effects were observed for vitality, indicating that higher levels of symptoms of depression in patients and spouses were associated with lower vitality in their partners. In study IV, couples’ core and secondary illness beliefs were revealed. From the core illness belief that “the heart is a representation of life,” two secondary illness beliefs were derived: AF is a threat to life, and AF can and must be explained. From the core illness belief that “change is an integral part of life,” two secondary illness beliefs were derived: AF is a disruption in our lives, and AF will not interfere with our lives. Finally, from the core illness belief that “adaptation is fundamental in life,” two secondary illness beliefs were derived: AF entails adjustment in daily life, and AF entails confidence in and adherence to professional care. In conclusion, the thesis result suggests that illness, in terms of cardiac disease and AF, affected and influenced the couple on aspects such as making sense of AF, responding to AF, and mutually incorporating and dealing with AF in their daily lives. In the light of this, the thesis results suggest that clinicians working with persons with AF and their partners should employ a systemic view with consideration of couple’s reciprocity and interdependence, but also have knowledge regarding AF, in terms of pathophysiology, the nature of AF (i.e., cause, consequences, and trajectory), and treatments. A possible approach to achieve this is a clinical utilization of an FSN based framework, such as the FamHC. Even if a formalized FSN framework is not utilized, partners should not be neglected but, rather, be considered a resource and be a part of clinical caring activities. This could be met by inviting partners to take part in rounds, treatment decisions, discharge calls or follow-up visits or other clinical caring activities. Likewise, interventional studies should include the couple as a unit of analysis as well as the target of interventions.

BACKGROUND: Atrial Fibrillation (AF) is the most common cardiac arrhythmia, affecting over 3 million Americans. Many people who suffer from AF have pre-disposing factors such as hypertension, ischemia, and structural heart disease, but recent research has also demonstrated the importance of genetic factors that can contribute to AF. In the present study, we sought to determine the causative mutation in a family with AF, atrial septal, and ventricular septal defects. METHODS: We evaluated a pedigree with 16 family members, one of whom had an ASD, one a VSD, and three had AF. Exome sequencing was performed on three of the five affected family members followed by confirmation with Sanger sequencing in all family members. A separate cohort from the MGH AF Study with early-onset AF (age at onset 47.1 ± 10.9 years, 79.3% male) was also screened for mutations using a combination of Sanger sequencing and high resolution melting. Variants were then functionally characterized using reporter assays in a mammalian cell line using wild-type and mutant constructs driving NPPA, αMHC and NPPB promoter reporters. RESULTS: Exome sequencing of the three affected individuals in the family identified a highly conserved mutation, R585L, in the transcription factor gene, GATA6. We also identified three additional GATA6 variants (P91S, A177T, and A543G) in the cases with early-onset AF from the MGH AF Study. We found that three of the four variants had a marked upregulation of luciferase activity (R585L; 4.1 fold, p<0.0001; P91S; 2.5 fold, p=0.0002; A177T; 1.7 fold, p=0.03). Additionally, when co-overexpressed with GATA4 and MEF2C, all GATA6 variants exhibited upregulation of the αMHC and NPPA activity compared to control. CONCLUSION: Overall, we found gain-of-function mutations in GATA6 in both a family with early-onset AF and atrioventricular septal defects as well as in patients with sporadic, early-onset AF. This evidence suggests that specific gain of function mutations in GATA6 contribute to the development of AF. / 2017-06-16T00:00:00Z

Atrial Fibrillation (AF) is a debilitating heart rhythm disorder affecting over 2.7 million people in the US and over 30 million people worldwide annually. It has a high correlation with causing a stroke and several other risk factors, resulting in increased mortality and morbidity rate. Currently, the non-pharmocological therapy followed to control AF is catheter ablation, in which the tissue surrounding the pulmonary veins (PVs) is cauterized (called the PV isolation - PVI procedure) aims to block the ectopic triggers originating from the PVs from entering the atrium. However, the success rate of PVI with or without other anatomy-based lesions is only 50%-60%. A major reason for the suboptimal success rate is the failure to eliminate patientspecific non-PV sources present in the left atrium (LA), namely reentry source (a.k.a. rotor source) and focal source (a.k.a. point source). It has been shown from several animal and human studies that locating and ablating these sources significantly improves the long-term success rate of the ablation procedure. However, current technologies to locate these sources posses limitations with resolution, additional/special hardware requirements, etc. In this dissertation, the goal is to develop an efficient algorithm to locate AF reentry and focal sources using electrograms recorded from a conventionally used high-resolution multi-pole diagnostic catheter. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

Thèse d'exercice : Médecine. Médecine générale : Nantes : 2007. / Bibliogr.

Background: Ventricular fibrillation (VF) is associated with dysfunctional cardiac calcium cycling and poor survival. We hypothesized dantrolene improves survival following VF by stabilizing calcium dysregulation. Methods: VF was induced in 26 healthy Yorkshire pigs and left untreated for 4 min followed by 3 min of CPR and defibrillation. Dantrolene was infused during CPR. Rabbit hearts (n=14) were studied to evaluate the effect of dantrolene on VF-induced calcium cycling dysfunction. Results: Survival was higher in the dantrolene group. (85% vs. 39%, P=0.01) Dantrolene-treated pigs required significantly lower defibrillation energy level. (150J vs. 650J, P<0.05) Systolic pressure was significantly higher during the post-defibrillation period in the dantrolene group. (P=0.001) In rabbit hearts, dantrolene significantly mitigated the amplitude of VF-induced diastolic calcium elevations and increased the calcium alternans threshold. (P<0.05) Conclusion: Our findings suggest dantrolene facilitates successful defibrillation, prevents myocardial stunning and improves survival following VF. The effects are mediated through normalizing the VF-induced dysfunctional calcium cycling.

Background: Ventricular fibrillation (VF) is associated with dysfunctional cardiac calcium cycling and poor survival. We hypothesized dantrolene improves survival following VF by stabilizing calcium dysregulation. Methods: VF was induced in 26 healthy Yorkshire pigs and left untreated for 4 min followed by 3 min of CPR and defibrillation. Dantrolene was infused during CPR. Rabbit hearts (n=14) were studied to evaluate the effect of dantrolene on VF-induced calcium cycling dysfunction. Results: Survival was higher in the dantrolene group. (85% vs. 39%, P=0.01) Dantrolene-treated pigs required significantly lower defibrillation energy level. (150J vs. 650J, P<0.05) Systolic pressure was significantly higher during the post-defibrillation period in the dantrolene group. (P=0.001) In rabbit hearts, dantrolene significantly mitigated the amplitude of VF-induced diastolic calcium elevations and increased the calcium alternans threshold. (P<0.05) Conclusion: Our findings suggest dantrolene facilitates successful defibrillation, prevents myocardial stunning and improves survival following VF. The effects are mediated through normalizing the VF-induced dysfunctional calcium cycling.