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.
All of these can be symptoms of paroxysmal atrial fibrillation. Atrial fibrillation (AF or AFib) happens when the atria (upper chambers of the heart) lose their regular rhythm and beat chaotically. When this happens, blood isnât really streaming through the heart and body efficiently. This inefficient flow can cause blood to pool inside the atria, increasing the risk of blood clots.