Can We Predict Outcomes in Atrial Fibrillation?

Abstract

Atrial fibrillation (AF) is the most common arrhythmia encountered by generalists and cardiologists alike. Much of the attendant morbidity from AF arises from systemic embolic complications which are effectively reduced with utilization of anti-platelet and/or anticoagulant therapy. The systemic embolic complications of AF and the medical therapy to attenuate these risks are very well established. Through the course of this review, we aim to highlight the complex relationship between AF and other, ''non-embolic'' outcomes. The presence of AF has been demonstrated to be associated with a 1.5 to 2-fold increase in mortality across numerous observational cohorts. Still further, AF frequently coexists with heart failure, whether as a causative factor or a consequence of underlying structural heart disease or neurohumoral derangement, where its presence is associated with worse clinical outcomes. Whether AF is an independent risk factor for acute coronary syndromes (ACS) remains controversial, though its occurrence in patients with ACS has been shown to be associated with adverse outcomes both in observational cohorts as well as clinical trial populations. Individuals with AF have a 1.5 to 3-fold increase in the rate of hospitalization and are at elevated risk for other arrhythmic disorders including both bradyarrhythmias as well as tachyarrhythmias. AF leads to considerable morbidity and mortality for patients and exacts a tremendous financial toll on the healthcare system-estimated to range from $6.0 to $26.0 billion. Given the current demographic transition in developed countries, the prevalence of AF will continue to increase and the need for refined approaches to risk stratification and pharmacotherapeutic interventions to attenuate the burden on patients will only become more important. IntroductionAtrial fibrillation (AF) is the most common cardiac arrhythmia requiring medical attention. Its incidence and prevalence increase with advancing age, affecting nearly 10% of individuals age 80 years or older, and in the presence of concomitant cardiovascular (CV) disease.1 The estimated incremental costs of AF using current demographic data range from $6.0 to $26.0 billion.2 Much of the attendant morbidity from AF arises from systemic embolic complications that are effectively reduced with use of antiplatelet and/or anticoagulant therapy. In fact, well-established risk-stratification models exist to estimate embolic risk and enable patients and providers to make informed treatment decisions. However, in this review article we hope to synthesize information regarding the relationship between AF with other adverse outcomes, including mortality, heart failure (HF), acute coronary syndrome (ACS), other arrhythmias, and hospitalizations ( Figure 1) and ask whether a global risk model can be created for patients with AF.

A Review of the Relationship of Atrial Fibrillation and Acute Coronary Syndrome

“…While a narrative review by Desai et al in 2012 did not find a consistent association between AF and MI [7], more recent investigations have shown an association between AF and MI. The results of two large retrospective cohort studies are listed in Table 1.…”

Anthropometric parameters and the incidence of atrial fibrillation in older people: the PRO.V.A study

“…Atrial fibrillation (AF) is one of the most common cardiovascular diseases in adults and the elderly, with a prevalence of around 4% among those 60 to 70 years old, which rises to 10% to 17% in people over 80 years old . Among the possible risk factors for the onset of this arrhythmia, the impact of body size, in particular excess weight or tall stature, and central obesity are attracting increasing interest …”

MicroRNA Regulation and Cardiac Calcium Signaling

“…97 In the search for novel therapeutic approaches, disorders of cellular Ca 2+ handling and signaling are emerging as important pathophysiological contributors and targets. 98 AF can result from a wide range of cardiac conditions and, once initiated, AF induces remodeling changes that promote its own occurrence and maintenance ( Figure 6).…”