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Atrial fibrillation (AF) is the most common sustained rhythm disorder in clinical practice, and both the prevalence and incidence of AF are increasing, largely owing to the aging of the population. Indeed, 50% of patients with AF are 75 years of age or older, and it is projected that by 2050, half of all patients with AF will be at least 80 years of age. In the past 10–15 years, much research has been devoted to understanding the basic mechanisms of AF in the aging heart and to developing more effective strategies for the diagnosis and treatment of AF in both younger and older patients. In this issue of the Journal, a series of six articles provides an overview of recent advances in AF focusing specifically on the older patient.
In the first article, one of us (MWR) describes current trends in the epidemiology of AF. An important observation is that the proportion of strokes attributable to AF increases exponentially with age. Also noted is the exceptionally high cost associated with AF, estimated at approximately $7 billion annually in the U.S. alone. In addition, the presence of AF is an independent marker for increased mortality, especially in women, and AF is associated with a significant reduction in quality of life in older adults.
In the second article, Drs. Wen Dun and Penelope Boyden review age-related changes in atrial structure and physiology that predispose older individuals to the development of AF. Structural changes include, most prominently, increased fibrous tissue and atrial dilatation, both of which foster abnormal patterns of electrical conduction. Aging is also associated with decreased calcium current and increased potassium current in atrial myocytes, resulting in altered impulse initiation and propagation, setting the stage for re-entrant arrhythmias, including AF.
Antithrombotic therapy is a cornerstone of treatment for AF in elderly patients, yet both warfarin and aspirin are underutilized, in part due to clinician uncertainty about the relative benefits and risks associated with these agents, especially in patients with multiple comorbid illnesses. Dr. Margaret Fang addresses this issue in her article, summarizing the available evidence and advocating a risk stratification approach to selecting an antithrombotic regimen in older patients. Importantly, in most elderly patients at moderate or high risk for stroke, the benefits of warfarin outweigh the risks of bleeding complications.
In the next article, Dr. D. George Wyse reviews recent studies comparing rate-control versus rhythm-control strategies in patients with AF, concluding that in patients with relatively few symptoms, rate-control is favored for the outcomes of mortality, hospitalization, and cost. For patients with limiting symptoms, rhythm-control may be preferred, but selection of an anti-arrhythmic agent is problematic due to the high frequency of side effects associated with available drugs. The prospect for “upstream” preventive therapies is also briefly discussed.
In recent years there has been increasing interest and utilization of catheter ablation techniques for definitive treatment of AF, primarily in younger patients. In his article, Dr. David Haines discusses the purported rationale for avoiding ablation procedures in older AF patients, but concludes that current literature supports the use of catheter ablation for selected elderly patients with symptomatic AF. He notes that outcomes are generally similar to those in younger patients, except for a slightly higher risk of procedure-related strokes.
In the last article of this series, Drs. Dierdre Lane and Gregory Lip address a critically important but understudied issue—the impact of AF and its treatment on quality of life in older patients. Most studies indicate that AF is associated with poorer physical and mental quality of life in older adults, especially women. Both rate-control and rhythm-control treatment strategies improve quality of life, primarily by reducing symptoms. Similarly, pulmonary vein isolation and ablation of the atrioventricular node with concomitant pacemaker implantation improve quality of life in symptomatic patients.
It has been our privilege to serve as guest editors for this special theme issue of the Journal. We would like to thank all of the authors for providing concise yet thorough and timely reviews of these topics, and we hope that you, the reader, will find these articles useful in your management of elderly AF patients. We welcome any comments you may have.