Some genes increase risk of atrial fibrillation.

However, tachycardia can be dangerous, depending on the speed and type of rhythm.

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.

The most common presenting symptoms are rapid weight loss, tachycardia (rapid heart rate), vomiting, diarrhea, increased consumption of fluids (polydipsia) and food, and increased urine production (polyuria).