Significance of AF
AF is an important arrhythmia for many reasons. First, it is common: current estimates reveal that more than 33 million individuals worldwide have AF.38 In the United States alone, it is estimated that between 3 and 5 million people have AF, and that by 2050 this number will exceed 8 million.39 Second, AF increases risk of stroke by an average of 5-fold.40 AF-related strokes are more severe than those not related to AF.41 Third, AF increases mortality, and has been linked to an increased risk of sudden death.42,43 Consistent with these prior studies, a recent Framingham study reported that those with recurrent or sustained AF had a higher multivariable-adjusted mortality compared with those with an isolated AF episode.44 Fourth, AF increases the risk of HF.45 Fifth, recent studies have linked AF with the development of dementia.46 Finally, AF causes a wide variety of symptoms, including fatigue and reduced exercise tolerance, and significantly impairs quality of life (QOL).47 It is notable that asymptomatic status is associated with similar (or worse) prognosis compared with symptomatic status.48 AF is also important when considered in terms of use of health care resources and cost. In the United States, AF accounts for more than 450,000 hospitalizations yearly and has contributed to more than 99,000 deaths.49,50 AF has been reported to increase annual health care costs by $8700 per patient, resulting in a $26 billion annual increase in U.S. health care costs. Although studies have not been performed to address the question of whether AF control with catheter ablation impacts the morbidity and mortality associated with AF, it is notable that emerging data have revealed that persistent forms of AF are associated with a significant increase in thromboembolism and death compared with PAF.51
The morbidity and mortality associated with AF provide a rationale to maintain sinus rhythm. Given the anticipated enormous public health impact of AF, proven interventions to reduce the risk of stroke, HF, cognitive impairment, and mortality are direly needed. Large, prospective, multicenter, randomized clinical trials will help address whether sinus rhythm achieved with ablation techniques lowers morbidity and mortality compared with rate control alone or treatment with antiarrhythmic therapy. These studies will also best define the patient population that will derive the most benefit. Until the results of these types of clinical trials are available, it must be recognized that the only proven benefit of AF ablation remains the reduction of symptoms and an improvement in QOL.