Date of Award

2023

Degree Name

Doctor of Medical Science

Schools and Centres

Medicine

First Supervisor

Jim Codde

Second Supervisor

David Playford

Abstract

Residing on opposite sides of the Strait of Messina between Sicily and Calabria, Scylla and Charybdis were mythical sea monsters (one a fearsome creature, the other a deadly whirlpool) described by Homer. For anyone seeking to navigate that narrow and treacherous passage, avoid one of these lethal threats and you would be devoured by the other. For many populations around the world, the conundrum of successfully preventing and/or treating heart failure (HF) to increase longevity, only to increase the probability that it will increase the number of people living with and dying from atrial fibrillation (AF), represents a conundrum of Scylla and Charybdis dimensions. So how did this happen? In the late 20th Century, heart disease was characterised by a predominance of middle-aged men suffering often fatal acute coronary events. However, this pattern began to change due to the combination of two key factors. Firstly, in high-income countries at least, there were increasingly successful attempts to prevent and treat acute coronary events (thereby reducing premature mortality rates). Secondly, the vanguard of the Post- War Baby Boomer generation had reached their sixth decade of life, with more to come. Thus, more people were living longer with an ageing/damaged heart and those numbers would inevitably rise.

The first manifestation of this phenomenon was an increasing number of HF cases (well before a noticeable increase in AF cases). This mandated increasing recognition that HF was a discrete physical entity/syndrome that needed to be more widely recognised. This trend (rising HF cases) meant that the main burden of heart disease was shifting from the fifth/sixth decade of life with a male predominance, to the seventh/eighth decade of life affecting both men and women. Unless urgently addressed, it seemed clear that HF cases would overwhelm future health care services. At this point in time, AF attracted far less scrutiny because case numbers remained low. However, fuelled by the inevitable wave of ageing Baby Boomers, combined with successful attempts to prolong the lives of those affected by “earlier” forms of heart disease (including HF), it was inevitable, therefore, that more people would be successfully reaching their eight/ninth decade of life. Thus, the perfect “recipe” for a rising tide of AF had emerged.

So does every individual face a Scylla and Charybdis choice between HF and AF – of course not! However, as a society in successfully recognising and treating a rising epidemic of HF, we inevitably fuelled (as some of us were predicting) a consequential epidemic of AF. In simple terms, unless we could “cure” heart disease – we had no choice in a classical Scylla and Charybdis conundrum, by solving/avoiding one problem and then creating/running into, another. Thus, as with HF 10-20 years earlier, AF has since challenged health care systems to cope with the demands it places on all healthcare services. Concurrent to the rise of AF, HF now represents a sustained threat to the heart health of successfully ageing populations worldwide (creating a “twin epidemic”), with AF and HF often occurring in the same person.

It is within this context, that this thesis describes two closely related portfolios of research (comprising >100 primary and topic-related, original reports) that were instrumental in – 1) Describing the evolving burden of disease imposed by HF and AF, 2) Developing targeted, multidisciplinary management programs with the capacity to simultaneously reduce the risk of recurrent hospitalisation and prolong the lives of vulnerable people affected by one or both of these deadly/disabling conditions, and 3) Considering their broader impact in vulnerable/disadvantaged communities and regions of the world (from Central Australia to Sub-Saharan Africa).

In addition to describing how this portfolio of research represents a cogent investigation of two critical aspects of HF and AF (i.e., what is the pattern of disease and how can its impact from an individual to societal perspective be attenuated?), this thesis outlines the concrete impact these research reports have made in our collective awareness, understanding and response to them.

My own (small) contribution to this field of research includes a series of important studies generating new knowledge (e.g., the prognostic impact and economic burden of HF and AF) and trials of HF and AF management that have directly influenced the provision and design of new health programs and services. Consistent with this impact, the 33 original research studies presented in this thesis have attracted >100 individual citations in Expert Clinical Guidelines/Consensus Reports over the last 20 years.

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