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.
RISK FACTORS/CAUSES As people age, the risk for developing atrial fibrillation increasesâfrom less than 1% in individuals under 60 years old to more than 6% in individuals over 80 years old. Men tend to have a higher risk of developing atrial fibrillation than women, and at an earlier age.