Causes of Atrial Fibrillation

Many conditions can cause disorganized electrical activity in the atria to develop. In many cases, a "leaky" or a sticky (stenotic) mitral valve can result in an enlarged (dilated) atria.

Patients with a history of high blood pressure (hypertension), can develop atrial fibrillation (AFib, AF), because high blood pressure eventually begins to affect the atria.

Blockages in the arteries that supply the heart with blood (coronary arteries), heart attack, and overactive thyroid gland can also lead to atrial fibrillation.

Excessive consumption of alcohol acts as a toxin on the heart, and patients who binge drink or chronically drink large amounts of alcohol are at risk for developing atrial fibrillation.

Patients with heart failure, in which the left ventricle, the heart's main pumping chamber, does not pump blood normally, may develop atrial fibrillation as blood "backs up" from the left ventricle into the left atrium.

Rarely, a blood clot develops in the legs and travels to the lungs, causing a pulmonary embolus that can trigger atrial fibrillation.

Pericarditis (inflammation of the tissue that surrounds the heart, the pericardium) can irritate the atria and lead to AFib.

In some patients, there simply is no clear cause for the condition.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 01 Jul 2000

Last Modified: 31 Mar 2014