Epidemiology, pathogenesis and management of atrial fibrillation

Abstract

Atrial fibrillation is the most common heart rhythm disorder. Once considered to be a benign condition, it is now known to be associated with significant morbidity and mortality. The rising incidence and prevalence of atrial fibrillation has thus led to growing concern by clinicians and policymakers. In recent years, there have been marked strides in our mechanistic understanding of atrial fibrillation that, coupled with technological advances, have allowed for many new therapies. Despite the resultant explosion in research on atrial fibrillation, however, innumerable uncertainties regarding this intriguing arrhythmia still remain. This has provided fertile ground for the work undertaken as part of this thesis and future research on this condition. Previous studies contributing to our current understanding of atrial fibrillation are first reviewed in Chapter 1. Chapter 2 subsequently characterises the population burden of atrial fibrillation on the Australian healthcare system by analysing nationwide trends in hospitalisations. To provide some insight into the determinants of such healthcare utilisation, and how they may potentially be modified, Chapter 3 analyses relevant patient- and management-specific factors as they pertain to these trends. Data on two other cardiovascular conditions, myocardial infarction and heart failure, are contrasted with those for atrial fibrillation to provide context and insight into these trends. Given the emerging epidemic of obesity, Chapter 4 characterises the contribution of obesity to the risk of atrial fibrillation in various clinical situations by undertaking comprehensive systematic reviews and meta-analyses. In Chapter 5, the possible contribution of pericardial fat in mediating the the relationship between obesity and atrial fibrillation is further studied. In Chapter 6, race-specific differences in atrial fibrillation are explored by analysing differences in the prevalence of atrial fibrilllation between Indigenous and non-Indigenous Australians. An insight into possible mechanisms underlying these differences are subequently provided by studying cardiac structural characteristics. Given the greater prevalence of atrial fibrillation and burden of stroke experienced by Indigenous Australians, in Chapter 7 the race-specific management of atrial fibrilation is characterised with regards to anticoagulation practices. Finally, insights into the epidemiology, pathogenesis and management of atrial fibrillation from the research presented in this thesis are placed in the context of the previous literature in Chapter 8, before possible directions for future studies on atrial fibrillation are discussed in Chapter 9.