DEFINITION of 'Attribution Rules'. A set of rules created by Canada Revenue Agency (CRA) that prevents investors from transferring assets between family members with the intention of avoiding taxes. Next Up.
Causes of atrial fibrillation. The exact cause of atrial fibrillation is unknown, but it's more common with age and affects certain groups of people more than others. Atrial fibrillation is common in people with other heart conditions, such as: 1  high blood pressure (hypertension). 2  atherosclerosis.3  heart valve disease.4  congenital heart disease.auses of atrial fibrillation. The exact cause of atrial fibrillation is unknown, but it's more common with age and affects certain groups of people more than others. Atrial fibrillation is common in people with other heart conditions, such as: 1  high blood pressure (hypertension). 2  atherosclerosis.
According to the Mayo Clinic, fewer than one in every 100 people in their 50s has AF, but about 10 out of every 100 in their 80s experience it. The most common cause of atrial fibrillation is longstanding, uncontrolled high blood pressure and heart disease. Additionally, atrial fibrillation is the most common complication after heart surgery. An entire spectrum of seemingly unrelated conditions can send the atria into overdrive..