Risk factors for atrial fibrillation: Not always severe heart disease, not always so 'lonely'.

The precise mechanisms that cause atrial fibrillation (AF) are not completely understood. Clinicians should ask themselves whether AF is truly 'lone' or is the effect of an underlying, 'masked' disorder. Atrial fibrillation shares strong epidemiological associations with other cardiovascular diseases such as heart failure, coronary artery disease, valvular heart disease, diabetes mellitus and hypertension. In this review, we discuss the 'new risk factors' and the mechanisms by which they lead to AF. Based on the most recent studies, we present the current knowledge about the relationship between AF occurrence and the following disorders: metabolic syndrome and its components, sleep apnea and inflammation. Moreover, some aspects of the influence of lifestyle (alcohol consumption and physical activity) on AF events are described.