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.
It is extremely rare for atrial fibrillation to develop in younger patients, unless they have an underlying heart condition. Experts say there are many cases in which the cause of the atrial fibrillation was never found. Here is a list of the most common causes: 1  Hypertension-high blood pressure.2  Coronary artery disease-also known as coronary heart disease. 3  Plaque builds up inside the coronary arteries.t is extremely rare for atrial fibrillation to develop in younger patients, unless they have an underlying heart condition. Experts say there are many cases in which the cause of the atrial fibrillation was never found. Here is a list of the most common causes: 1  Hypertension-high blood pressure.