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.
Atrial Fibrillation. Atrial fibrillation (AF) is characterized by rapid and irregular activation of the atrium. It may be recurrent (paroxysmal) or permanent (chronic). During AF, atrial cells fire at rates of 400-600 times per minute. The filtering function of the atrioventricular node prevents the conduction to the ventricles and therefore results in ineffective cardiac contraction.