Some genes increase risk of atrial fibrillation.

Also, the sub tricuspid region may be difficult to distinguish from the atrioventricular sulcus, which is rich in fat.

The Bainbridge reflex, also called the atrial reflex, is an increase in heart rate due to an increase in central venous pressure.

Differences in the atypical form are the lack of syndactyly, the presence of musculoskeletal problems (particularly hyperflexible joints), and atrial fibrillation.

The risk of emboli forming in idiopathic AF depends on other risk factors such as increasing age, hypertension, diabetes, recent heart failure, or previous stroke.