Background: Geriatric impairments and obstructive sleep apnea (OSA) are prevalent among patients with atrial fibrillation (AF) and adversely impact patient’s long-term outcomes. Little is known, however, about the association between OSA and frailty, cognitive performance, and AF-related quality of life in older men and women with AF. Objective: To examine the association of OSA with frailty, cognitive performance, and AF- related quality of life among older adults with AF. Methods: Data from the Systemic Assessment of Geriatrics Elements-AF study were used which includes participants ≥ 65 years with AF and a CHA2DS2-VASc ≥ 2. Multivariable adjusted logistic regression models were used to examine the association between OSA, as measured by the STOP-BANG questionnaire, and geriatric impairments including frailty, cognitive performance, and AF-related quality of life. Results: A total of 970 participants with AF (mean age 75 years, 51% male) were included in the analysis. Among the 680 participants without a medical history of OSA, 179 (26%) participants had low risk of OSA, 360 (53%) had an intermediate risk, and 141 participants (21%) had a high risk for OSA. Compared to those with low risk of OSA, those at intermediate or high risk for OSA were significantly more likely to be frail (aOR= 1.66, 95% CI: 1.08–2.56; aOR= 3.00, 95% CI: 1.69-5.32, respectively) after adjusting for sociodemographic, clinical, and health behavioral variables. Risk of OSA was not associated with cognitive performance and AF- related quality of life after adjusting for several potentially confounding factors. Conclusions: Older adults with AF who are at intermediate or high risk for OSA have a greater likelihood of being frail. Our findings identify a group of patients at high risk who would benefit from early screening for OSA. Future longitudinal studies are needed to assess the effect of OSA treatment on frailty, physical functioning, and QoL among patients with AF.

Cardiovascular diseases are the leading cause of morbidity and mortality worldwide. Congenital heart disease (CHD) is a risk factor for premature cardiovascular complications. Great advances have occurred in the past years leading to the identification of several genes essential for proper cardiac formation such as GATA4/5/6 mutated in some individuals with CHD. GATA6 is a zinc finger transcription factor whose presence is crucial for early embryonic development. GATA6 is expressed in many cell types of the heart including myocardial, endocardial, neural crest, and vascular smooth muscle. In human, mutations in GATA6 result in variable cardiac phenotypes. The objective of this thesis was to determine the roles that GATA6 play in the different cell types of the heart and to elucidate the molecular basis of the cardiac defects associated with Gata6 haploinsufficiency. For this, a combination of cell and molecular techniques were used in vitro and in vivo. First, we show that Gata6 heterozygozity leads to RL-type bicuspid aortic valve (BAV)- the most common CHD affecting 2% of the population. GATA6-dependent BAV is the result of disruption of valve remodeling and extracellular matrix composition in Gata6 haploinsufficient mice. Cell-specific inactivation of one Gata6 allele from Isl-1 positive cells, but not from endothelial or neural crest cells, recapitulates the phenotype of Gata6 heterozygous mice revealing an essential role for GATA6 in secondary heart field myocytes during valvulogenesis. We further uncovered a role for GATA6 as an important regulator of the cardiac conduction system and revealed that GATA6 expression regulates the activity of the cardiac pacemaker. GATA6 exerts its role via regulation of the cross-talk among the different cell types of the SAN. Lastly, some CHDs are characterized by abnormalities of both the limbs and the heart such as the Holt Oram syndrome (caused by mutation in TBX5 transcription factor). The molecular basis for limb-heart defects remain poorly understood. In the course of this work, we discovered that Gata6 haploinsufficiency resulted in a partially penetrant polysyndactyly (extra digits fused together) phenotype. Together, the data provide novel molecular and cellular insight into GATA6 role in normal and pathologic heat development. Our results also suggest that GATA6 should be added to the list of genes whose mutations are potentially associated with heart and limb abnormalities. Better knowledge of the molecular basis of CHD is a prerequisite for the development of diagnostic and therapeutic strategies to improve care of individuals with congenital heart disease.

INTRODUCTION: Research has consistently shown that sleep apnea is strongly associated with atrial fibrillation, with several lines of evidence demonstrating that this relationship is bidirectional and that each condition predisposes to and/or exacerbates the other. Many studies have suggested potential pathophysiologic mechanisms underlying this relationship, and that sleep apnea and atrial fibrillation share many of the same cardiovascular risk factors further implies that multiple pathways are likely involved in the mechanistic link between the two. Although the sleep apnea-atrial fibrillation relationship is quite established, numerous aspects of this association still require further study, such as the role of gender and the potential impact of positive airway pressure therapy. A deeper understanding of how these individual factors may be involved in the interrelationship between sleep apnea and atrial fibrillation has important clinical implications, such as for risk stratification and screening of patients. Thus, this study aims to further understand the different aspects and modulating factors of the sleep apnea-atrial fibrillation link, focusing on central sleep apnea as less is known about the central sleep apnea-atrial fibrillation relationship. METHODS: A total of 153 patients, originally seen at the cardiac electrophysiology clinic at Beth Israel Deaconess Medical Center and subsequently offered home sleep apnea testing, were included in this study. Several databases – home sleep apnea testing results, polysomnography reports, electrocardiogram reports and patient management systems – were used to obtain a variety of data on sleep pathology, high loop gain status, left ventricular ejection fraction and positive airway pressure therapy efficacy and compliance. Patients were considered to have central sleep apnea if home testing results demonstrated a central apnea-hypopnea index of 5 or greater and/or if the patient was documented as having high loop gain on polysomnography. Data were analyzed using the Statistical Package for Social Sciences software in order to examine how factors such as gender and therapy use may affect the sleep apnea-atrial fibrillation relationship, in a patient population with sleep pathology of at least moderate severity. RESULTS: Statistical analysis revealed significant sleep disturbances in the central sleep apnea patients compared to the non-central sleep apnea patients. Gender was found to be significantly associated with central sleep apnea, but not obstructive sleep apnea. When postmenopausal (age≥51) women were analyzed, very few patients met the study criteria for central sleep apnea, yet the majority were documented as having atrial fibrillation. As expected, positive airway pressure therapy was found to be beneficial for all users, but the common pattern of declining compliance to therapy was seen as adherence decreased over the course of three months. Of the select central sleep apnea patients who had sufficient data available, comparison of positive airway pressure therapy and cardiac data revealed possible benefits to cardiac health with compliant use of positive airway pressure therapy. CONCLUSION: Through examining different aspects of the sleep apnea-atrial fibrillation relationship, this study found promising evidence showing that gender and positive airway pressure therapy play important roles. Further studies, with larger sample sizes, need to be conducted in order to fully understand the specific impact of factors such as gender, gender and age and positive airway pressure therapy on the risks and outcomes in patients with sleep apnea and/or atrial fibrillation, and how these factors may change depending on the type of sleep apnea. Finally, these results further highlight the growing need for an effective collaborative care model between cardiologists and sleep medicine clinicians, as the management of patients with sleep apnea and atrial fibrillation requires an interdisciplinary approach in order to deliver the most optimal patient care.

Department of Social and Clinical Pharmacy, Faculty of Pharmacy in Hradec Králové, Charles University Pulse check in pharmacies III Author: Ivana Vasilišinová Supervisor: PharmDr. Anna Rejmanová, Ph.D. Consultant: PharmDr. Kateřina Malá, Ph.D. Introduction: Atrial fibrillation (AF) is the most common supraventricular arrhythmia. It is often asymptomatic. If left untreated, the patient is at significant risk of complications, especially of ischemic stroke (IS) and heart failure. These complications can be effectively prevented by early detection of AF and initiation of treatment. Population screening activities performed at pharmacies could serve as an useful tool for detection of latent arrhythmias. Objective: The aim of this diploma thesis was to analyze the heart rate, blood pressure, selected symptoms and risk factors for IS in real patient population and to raise their awareness in the field of heart rate monitoring. Methodology: The measurement took place in a public pharmacy at an outpatient clinic in Prague during the one-day campaign "Pharmacy Day" (18/6/2020) and subsequent data collection (12/2020-02/2021). During this time, education in atrial fibrillation, the heart rate and blood pressure measurement and also evaluation of the selected symptoms and risk factors for the possible future...

Die Ergebnisse dieser Arbeit lassen vermuten, dass die Connexin43 Anordnung an der der Zellmembran humaner Herzmuskelzellen pharmakologisch beeinflussbar ist. Es ist bekannt, dass sich Connexin43 an der polaren und lateralen Zellmembran beim Vorhofflimmern und Sinusrhythmus unterschiedlich anordnet. Während beim Sinusrhythmuspatienten Connexin43 kaum an der lateralen Zellmembran zu finden ist, zeigt sich beim Vorhofflimmern vor allem an der lateralen Zellmembran eine verstärkte Connexin43 Anhäufung. Neben dem Rhythmustyp hat auch β-Adrenozeptorstimulation Einfluss auf die Connexin43 Expression. Aus diesem Grund untersucht die vorliegende Arbeit den Einfluss einer pharmakologischen Blockade der β-Adrenozeptoren durch Betablocker. Dafür wurden 38 die untersuchten Patienten anhand ihres Rhythmustyps, ihrer kardialen Begleiterkrankung und ihrer Pharmakotherapie (Betablocker: ja/nein) unterteilt und neben deren klinischen Daten ihre intraoperativ gewonnenen Herzohrbiopsien immunhistochemisch gefärbt und anschließend ausgewertet. Dabei zeigte sich, dass es zum einen zu einer unterschiedlichen Anordnung von Connexin43 bei den beiden Rhythmustypen kommt. Während beim Sinusrhythmus Connexin43 vor allem polar an der Zellmembran zu finden ist, ist es beim Vorhofflimmern vor allem an den lateralen Zellgrenzen zu finden. Betablockade geht hierbei vor allem beim Patienten mit Vorhofflimmern und Mitralklappenvitium mit einer Reduktion der Lateralisierung und einem positiven Effekt auf die Polarisierung einher.

Our objective was to determine whether atrial fibrillation (AF) results from excessive activation of intrinsic cardiac neurons (ICNs) and, if so, whether select subpopulations of neurons therein represent therapeutic targets for suppression of this arrhythmogenic potential. Trains of five electrical stimuli (0.3-1.2 mA, 1 ms) were delivered during the atrial refractory period to mediastinal nerves (MSN) on the superior vena cava to evoke AF. Neuroanatomical studies were performed by injecting the neuronal tracer DiI into MSN sites that induced AF. Functional studies involved recording of neuronal activity in situ from the right atrial ganglionated plexus (RAGP) in response to MSN stimulation (MSNS) prior to and following neuromodulation involving either preemptive spinal cord stimulation (SCS; T 1-T 3, 50 Hz, 200-ms duration) or ganglionic blockade (hexamethonium, 5 mg/kg). The tetramethylindocarbocyanine perchlorate (DiI) neuronal tracer labeled a subset (13.2%) of RAGP neurons, which also colocalized with cholinergic or adrenergic markers. A subset of DiI-labeled RAGP neurons were noncholinergic/nonadrenergic. MSNS evoked an ~4-fold increase in RAGP neuronal activity from baseline, which SCS reduced by 43%. Hexamethonium blocked MSNS-evoked increases in neuronal activity. MSNS evoked AF in 78% of right-sided MSN sites, which SCS reduced to 33% and hexamethonium reduced to 7%. MSNS-induced bradycardia was maintained with SCS but was mitigated by hexamethonium. We conclude that MSNS activates subpopulations of intrinsic cardiac neurons, thereby resulting in the formation of atrial arrhythmias leading to atrial fibrillation. Stabilization of ICN local circuit neurons by SCS or the local circuit and autonomic efferent neurons with hexamethonium reduces the arrhythmogenic potential.

Background/objectives: Patients with obstructive sleep apnea (OSA) have an increased the risk of developing atrial fibrillation (AF). However, it remains unclear if patients with OSA carry a higher risk of recurrent AF after successful catheter ablation. This meta-analysis was conducted (1) to evaluate the association between OSA and recurrent AF after catheter ablation, and (2) to assess the effect of continuous positive airway pressure (CPAP) on the risk of recurrent AF in patients with OSA. Methods: A comprehensive literature review was conducted using MEDLINE, EMBASE, Cochrane databases from inception through July 2017 to identify studies that evaluated the risk of recurrent AF after successful catheter ablation in patients with OSA were included. Effect estimates from the individual study were extracted and combined using random-effect, generic inverse variance method of DerSimonian and Laird. Results: Seven observational studies with a total of 4572 patients AF after successful catheter ablation were enrolled. Compared to patients without OSA, the pooled OR of recurrent AF in patients with OSA was 1.70 (95% CI, 1.40-2.06, I2 = 0). Among OSA patients with AF after successful catheter ablation, the use of CPAP was significantly associated with decreased risk of recurrent AF with pooled OR of 0.28 (0.19-0.40, I2= 0). Egger's regression asymmetry test was performed and showed no publication bias for the associations of OSA and CPAP with recurrent AF. Conclusions: Our meta-analysis suggested a significant association between OSA and recurrent AF after catheter ablation. The use of CPAP in patients with OSA is associated with reduced risk of recurrent AF after catheter ablation.

The association between non-alcoholic fatty liver disease (NAFLD) and atrial fibrillation (AF) has been suggested by recent epidemiological studies although the results were inconsistent. This meta-analysis was conducted to summarize all available data. Methods A comprehensive literature review was conducted using MEDLINE and EMBASE database through May 2017 to identify all studies that reported the risk of AF among patients with NAFLD versus those without NAFLD. Effect estimates from each study were extracted and combined together using the random-effect, generic inverse variance method of DerSimonian and Laird. Results Of 1009 studies, 5 studies (two cross-sectional studies and three cohort studies) with 238,129 participants met the eligibility criteria and were included in the meta-analysis. The risk of AF in patients with NAFLD was significantly higher than subjects without NAFLD with the pooled risks ratio of 2.06 (95% confidence interval, 1.10–3.85). The statistical heterogeneity was high with an I2 of 78%, which was the major limitation of this meta-analysis. Conclusions A significantly increased risk of AF among patients with NAFLD was demonstrated in this study.

Atrial fibrillation, long QT syndrome, and Middle East Respiratory Syndrome are three deadly human diseases for which genetic animal models are needed. From elucidating disease pathogenesis to facilitating the development of treatments, animal models are crucial for studying human disease. One of the most effective ways to generate specific animal models is through genetic modification. Historically, mice have been most widely used as genetically modified models, despite a number of limitations. New gene editing technologies such as CRISPR/Cas9 have made developing alternative genetic models that better recapitulate some human diseases better and more feasible. In this thesis, I describe my efforts to develop genetically modified goat and hamster models for atrial fibrillation and long QT syndrome, and genetically modified hamster models for Middle East Respiratory Syndrome. For long QT syndrome model development, I knocked out the KCNQ1 gene in goat fetal fibroblast cells and baby hamster kidney cells using the CRIPSR/Cas9 system. The knockout results in loss-of-function mutations, a known cause of human long QT syndrome. The edited goat fibroblast cells will be nuclear donors for future cloning experiments to produce live goats possessing the KCNQ1 knockout. The CRISPR gene targeting sgRNA/Cas9 vector, specific for the hamster KCNQ1, has been used for pronuclear injections to produce KCNQ1 knockout hamsters. For atrial fibrillation model development, I designed a single-stranded donor oligonucleotide that generates a KCNQ1 gainof-function mutation resulting in the disease. This oligonucleotide was injected into hamster embryos along with the KCNQ1 sgRNA/Cas9-expressing vector to generate hamsters containing the gain-of-function mutation. Finally, for Middle East Respiratory Syndrome model development, I established a breeding colony of human DPP4 transgenic hamsters in the STAT2 knockout background. Human DPP4 transgenic hamsters are susceptible to MERS-CoV infection, showing mild clinical signs and allowing viral replication in lung tissue. Giving these hamsters a STAT2 knockout background should promote a more severe disease progression. For all three diseases, the foundations for the development of genetic animal models have been laid.

I. Extensive experimental and clinical data suggest that certain electrical and structural changes develop in the atria of patients with atrial fibrillation (AF). These alterations are commonly referred as atrial remodeling and are considered to play a crucial role in the self-perpetuation of this arrhythmia. a. A hallmark of LA structural remodeling is the LA dilatation which is a predictor for progression to chronic AF and therapeutic failure as well. However, AF is associated not only with LA enlargement but also with asymmetrical changes in the left atrial geometry. b. Furthermore, the electrical remodeling is characterized by slower and asynchronous inter- and intra-atrial conduction that also contributes to the maintenance of AF. Some studies suggested a role of the conduction block in the Bachmann’s bundle, connecting the right and left atrium, in the AF pathophysiology and LA remodeling. II. Echocardiography and especially the tissue Doppler method can provide additional insight into the nature of the LA remodeling, because it allows the characterization of the intrinsic LA velocities. a. Using pulsed-wave tissue Doppler (PW-TDI) is possible to measure the interval from the onset of the surface P wave to the A´ velocity at the lateral mitral annulus as a representation of the total interatrial conduction time (TACT). In number of studies, it was demonstrated that prolonged TACT was associated with new-onset AF, AF after open heart surgery, and AF recurrences after electrical cardioversion and catheter ablation. b. An important limitation of the previous studies is that TACT has never been validated by direct measurements of the true electrical conduction in the LA. Moreover, it was assumed that the activation of the lateral MA must be the latest LA activation site. III. In this study, we sought to evaluate the feasibility of the PW-TDI as a simple and quick method to evaluate the LA asynchrony. For the purpose, we measured the time intervals from the onset of P-wave to the A´ (P-A´) in PW-TDI at 4 different left atrial sites next to mitral annulus (septal, lateral, anterior and inferior) in patients referred for electrophysiological study and catheter ablation because of atrial fibrillation or other arrhythmias. a. The differences between the longest and shortest P-A´ (DLS-PA´), as well as the standard deviation (SD-4PA´) of all 4 values were calculated as indexes for LA asynchrony. Importantly, LA asynchrony in patients with AF was compared with a matched control group of patients without history of AF. b. Moreover, the TACT was validated by comparing it with the actual electrical activation of the left atrium measured directly in the coronary sinus. For this purpose, the intervals between the onset of the P-wave and the local LA activation at the distal electrode pair of a catheter inserted in the coronary sinus were measured. c. Having in mind the ovoid LA shape and asymmetrical changes in LA geometry observed in patients with AF, we hypothesized that the lateral mitral annulus may not always be the latest activation spot. Therefore, we sought to determine the latest LA activation site exhibiting the longest P-A´ interval, as well as to describe the sequence of LA activation in AF patients and non-AF controls. IV. One hundred and thirty patients with AF (AF group) and 70 patients without a history of AF (non-AF control group) were examined prospectively using PW-TDI. a. Both groups were matched for the baseline characteristics, including LA diameter. The P-A´ interval measured with PW-TDI at the lateral LA showed a strong, positive, linear correlation with the P-A activation at the distal poles of the CS catheter at the lateral MA: Pearson r=0.708; P=0.0001. b. Asynchrony in the AF group was more pronounced in comparison to the non-AF control group. Patients in the AF group had longer DLS-PA´ as compared to controls: 37±16 msec. vs. 28±13 msec.; P=0.0001, as well as bigger SD-4PA´: 17±7 msec. vs. 13±5 msec.; P=0.0001. c. Furthermore, distinct patterns of LA activation were observed. Most AF patients (86.5%) showed an upward LA activation with inferior LA breakthrough, whereas the non-AF controls exhibited mostly a downward LA activation (65.5%), spreading from LA roof downwards. d. ROC analysis revealed that P-A´ at anterior LA successfully discriminated patients with AF from the non-AF controls (AUC 0.85, P<0.0001). A cut off value for P-A´ anterior > 55 msec. discriminated between AF patients and controls with 85% sensitivity; 81% specificity; positive predictive value of 0.898, and negative predictive value of 0.707. V. In conclusion, PW-TDI can be reliably used to assess the LA asynchrony. Patients with atrial fibrillation showed greater LA asynchrony in PW-TDI independently from the LA dimensions. For the first time, we described that LA activation showed 3 distinct patterns with the upward LA activation being the most frequently observed in patients with AF. Patients with AF demonstrated a prolonged P-A´ activation time at the anterior left atrium. P-A´ at anterior LA > 55 msec. discriminates between patients with AF and non-AF controls with high sensitivity and specificity. This method can be useful to identity patients at risk for occurrence of new-onset atrial fibrillation, as well as to assess the severity of the LA remodeling in order to improve the selection of patients for catheter ablation.:Table of Contents 1 Background 5 1.1 Mechanisms of initiation and perpetuation of atrial fibrillation 5 1.2 Left atrial remodeling in atrial fibrillation 7 1.3 Echocardiographic assessment of left atrial remodeling 8 1.4 Pathophysiology of interatrial conduction in atrial fibrillation 10 2 Objectives and methods 11 2.1 Study objectives 11 2.2 Methods 11 2.2.1 Echocardiography 13 2.2.2 Electrophysiological study 15 2.2.3 Statistical methods 16 3 Publication 17 4 Discussion 26 5 Limitations 30 6 Conclusion 31 7 Synopsis 32 8 References 36 9 Selbstständigkeitserklärung 47 10 Curriculum vitae and list of publications 48 11 Danksagung /Acknowledgments 56