Arrhythmia causes can include smoking, substance abuse, caffeine abuse, or the use of some prescription or over-the-counter drugs. Some people may develop arrhythmias as a reaction to stress or strong emotion. These kinds of arrhythmias, however, are typically minor and no cause for concern. Underlying conditions, including heart disease and thyroid dysfunction, can cause more serious arrhythmias. Conditions that lead to structural damage in the heart muscle are considered to be among the top causes of arrhythmia.
Heart conditions and defects are considered to be the most common arrhythmia causes. In a healthy heart, electrical impulses typically regulate the muscular contraction otherwise known as the heartbeat. In a heart damaged by disease or defect, these electrical impulses may fire irregularly, leading to irregularities in heartbeat, or arrhythmia.
Heart disease or defects typically cause arrhythmias for one of two reasons. Damage to the tissues of the heart muscle, or death of tissue in the heart, can cause the electrical impulses that regulate the heartbeat to fire improperly or irregularly. Defect and disease of the heart can also restrict blood flow to the heart. The heart usually can't beat regularly if it doesn't have a sufficient supply of blood.
Illnesses and defects that top the list of arrhythmia causes generally include cardiomyopathy, a condition in which the walls of the ventricles, or lower chambers of the heart, either stretch or thicken. If the ventricle walls stretch and the chambers become enlarged, the condition is usually known as dilated cardiomyopathy. If the ventricle walls thicken and the chambers become smaller, the condition is generally called hypertrophic cardiomyopathy. Either condition can render the heart muscle less efficient and inhibit blood flow to the muscle.
Arrhythmia causes can also include valvular heart diseases. Valvular diseases can cause the valves of the heart to become too narrow and even to leak. Defects in the valves of the heart often lead to enlargement of the chambers of the heart, impairing blood flow to the muscle.
Coronary artery disease, or CAD, is considered to be another of arrhythmia's common causes. Coronary artery disease typically leads to narrowing of the arteries in the heart. It's considered a leading cause of heart attack. When a heart attack occurs, a portion of the heart tissue typically dies, and scar tissue can form. Dead tissue in the heart and scar tissue on the heart muscle are typically considered top causes of arrhythmia.