Lone atrial fibrillation: Pathologic or not?

Risk factors between patients with lone and non-lone atrial fibrillation

Clinical factors such as tall stature, lean body mass, obstructive sleep apnea, alcohol or caffeine, smoking, endurance sports, and genetic factors are proposed as risk factors for lone atrial fibrillation (LAF). The KORAF (KORean Atrial Fibrillation) study is a retrospective multicenter registry that enrolled 3,570 consecutive atrial fibrillation (AF) patients. Data on risk factors were available for 2,133 patients, of whom 398 (18.7%) were identified as having LAF. In univariate analysis, patients with LAF were more likely to be men (82.4% vs 59.8%, P < 0.001) and current smokers (25.9% vs 15.6%, P < 0.01), alcohol drinkers (55.3% vs 31.2%, P < 0.01) and frequent consumers of caffeinated beverages (> 2 cups/day) (31.7% vs 19.3%, P < 0.01), and have a family history of AF (9.0% vs 2.6%, P < 0.001) than the non-LAF patients. Multivariate analysis showed that male gender (OR, 2.30; 95% CI, 1.61-3.27, P < 0.01), family history of AF (OR, 3.12; 95% CI, 1.91-5.12, P < 0.01), current alcohol use (OR, 2.01; 95% CI, 1.46-2.76, P < 0.01), and frequent caffeinated beverage consumption (OR, 1.66; 95% CI, 1.20-2.29, P < 0.01) were independently associated with LAF. In Korean patients, LAF is more closely associated with male gender, family history of AF, current alcohol and frequent caffeinated beverage consumption than non-LAF.

Lone AF - Etiologic Factors and Genetic Insights into Pathophysiolgy

Ever since atrial fibrillation (AF) was first recognized in young people (so called "lone" AF) over 4 decades ago, there has been increasing focus on determining the underlying pathophysiology of the condition. Although lone AF is presumed to be a highly heterogeneous disease, recent studies have identified novel risk factors such as inflammation, oxidative stress, endurance sports and genetics, for the arrhythmia. This monograph aims to highlight some of the recent advances in our understanding of the molecular pathophysiology of lone AF especially insight provided by contemporary genetic studies. These insights may provide novel therapeutic targets for treatment of this challenging arrhythmia in young patients.

Running, esophageal acid reflux, and atrial fibrillation: a chain of events linked by evidence from separate medical literatures

Using a previously described approach to generating novel medical hypotheses, this paper shows how two separate medical literatures taken together can suggest new information not apparent in either literature alone. Many studies have demonstrated that aerobic exercise in healthy people can induce esophageal acidic reflux that increases with the duration and intensity of exercise. Separately, independently of exercise, it has been shown that, in patients with gastroesophageal reflux, esophageal acid exposure can lead to atrial fibrillation (AF) and to other heart dysrhythmias. The two arguments together suggest that a regimen of excessive exercise may be conducive to AF mediated by acid reflux, an implicit, but unpublished, hypothesis. Proton pump inhibitors are widely used to treat gastroesophageal reflux. Remarkably, several small clinical trials of these drugs have been shown also to reduce symptoms and frequency of AF episodes in patients with comorbid acid reflux. Plausible mechanisms have been suggested. These small-scale tests in a highly restricted population may be of particular interest in the light of a possible exercise-reflux-AF causal chain of events in a broader population of athletes. Because the minimum degree of esophageal acidity exposure required to induce AF is unknown, further tests of proton pump inhibitors for that purpose are therefore merited without regard to any known prior reflux in a population of runners with lone AF. The prospect of reducing AF burden with a relatively benign agent is attractive in view of the limited options for effective treatment otherwise available. The study of arrhythmia and esophageal reflux in athletes may offer insights on the origin and natural history of lone atrial fibrillation.