Clinical Pearls & Morning Reports
Atrial fibrillation is often a marker for underlying heart and vascular disease. However, atrial fibrillation itself probably contributes to adverse outcomes by increasing the risk of stroke, diminishing cardiac performance, and exposing symptomatic patients to therapies that also have risks. Read the NEJM Clinical Practice Article here.
Q: What are the risk factors for atrial fibrillation?
A: Risk factors include older age, coronary artery disease, male sex, European ancestry, hypertension, obesity, smoking, diabetes mellitus, obstructive sleep apnea, and a family history of atrial fibrillation in a first-degree relative.
Q: Are the complications associated with atrial fibrillation equally common in men and women?
A: Atrial fibrillation is associated with an increased incidence of stroke (by a factor of approximately 4.0 in men and 5.7 in women), heart failure (by a factor of 3.0 in men and 11.0 in women), and dementia that is probably related to strokes and cerebral hypoperfusion (by a factor of 1.4 in both sexes). Atrial fibrillation increases the risk of death by a factor of 2.4 among men and by a factor of 3.5 among women.
A: Although the mechanisms are debated and presumably vary among patients, abnormalities of electrophysiological atrial myocytes as well as atrial structural changes, including fibrosis, probably create the electrical substrate that causes atrial fibrillation. The extent and severity of abnormalities increase with age and vary according to the type of atrial fibrillation. Paroxysmal atrial fibrillation occurs in episodes that terminate spontaneously, usually within hours to days. It is often initiated by rapid firing of myocardial triggers in the pulmonary-vein sleeves. Persistent atrial fibrillation continues unless it is interrupted by electrical or pharmacologic cardioversion, and it is associated with greater atrial fibrosis than paroxysmal atrial fibrillation. Pulmonary-vein triggers may still initiate the arrhythmia, but additional structural and electrophysiological changes allow atrial fibrillation to persist once it is initiated.
A: The management of atrial fibrillation has traditionally involved achieving adequate rate control, protection from thromboembolism and stroke, and reduction or elimination of symptoms, as well as the treatment of reversible risk factors. The decision regarding whether to pursue maintenance of sinus rhythm is shared between the patient and physician; this decision is informed by the effect of atrial fibrillation on the patient’s quality of life, risks, and the toxic effects of therapies. Attempts to maintain sinus rhythm should be considered when atrial fibrillation has not been persistent for more than 1 year or is paroxysmal and symptomatic. Maintenance of sinus rhythm is improved by the treatment of modifiable risk factors. A randomized trial involving 150 patients with atrial fibrillation showed that the addition of an intensive weight loss program to other therapies (including treatment and counseling for hypertension, sleep apnea, alcohol consumption, hyperlipidemia, and diabetes mellitus) resulted in weight loss as well as less atrial fibrillation and fewer symptoms of atrial fibrillation than the standard intervention.