Often, AF is asymptomatic. In some cases, however, AF causes these symptoms:
- shortness of breath
- fainting (in rare cases)
Atrial fibrillation affects about 2 million Americans. Most at risk are those with health problems that affect the cardiovascular system. Among the factors associated with AF are:
- high blood pressure
- coronary artery disease
- overactive thyroid (hyperthyroidism)
- rheumatic heart disease (caused by rheumatic fever)
- thyrotoxicosis (an excess of thyroid hormones)
- inflammation of the pericardium (the sac surrounding the heart)
- cardiomyopathy (progressive degeneration of the heart muscle)
- mitral valve stenosis (narrowing of the orifice between the left atrium and left ventricle)
- mitral insufficiency (backflow of blood from the left ventricle to the left atrium)
Atrial fibrillation (AF), the most common heart arrhythmia in the United States, occurs when the heart’s electrical system is disrupted. The main engineer of this system is the sinus node, or the heart’s natural pacemaker.
The sinus node directs electrical signals that travel first through the walls of the atria (the two upper chambers of the heart) and then through the walls of the ventricles (the two lower chambers). These impulses cause the heart to beat, typically at the rate of 60 to 100 beats per minute during normal physical activity. By comparison, the heart of a person with AF may beat 80 to 160 beats per minute or more.
In AF, the atria walls contract in a rapid, disorganized manner, quivering instead of beating normally. Consequently, some blood remains in the atria after each contraction and the ventricles don’t fill properly. Because the heart can’t keep pace with the body’s demand for blood under these circumstances, the person may feel weak or short of breath.
AF usually can be diagnosed with an electrocardiogram (ECG). But because atrial fibrillation tends to come and go, a single ECG may show normal results. In that case, your doctor may order ambulatory electrocardiography, a portable ECG machine that tracks your heart rhythm for about 24 hours.
Proper management is vital, as AF is a major cause of stroke. Your treatment plan depends on the reason for AF. Common causes include coronary artery disease, rheumatic heart disease, mitral valve conditions and an overactive thyroid. Methods to correct the problem may consist of lifestyle changes, medications that treat high blood cholesterol and hypertension, blood thinners and/or artery-clearing methods such as angioplasty or coronary artery bypass surgery (although this is rare). If AF persists despite treatment, your doctor may suggest cardioversion (a brief electric shock applied to the chest) to restore natural rhythm. If this is unsuccessful, catheter radiofrequency ablation is another option. During this procedure, an area of tissue in the atrioventricular node is destroyed to prevent the passage of electrical impulses. A pacemaker then is implanted to take the place of your heart’s natural one.
With proper treatment and management, most people with AF can enjoy healthy, active lives.