Some genes increase risk of atrial fibrillation.

There is also a small amount of cutaneous sensation carried by the nervus intermedius from the skin in and around the auricle (outer ear).

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

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