Atrial fibrillation (afib) is a common type of cardiac arrhythmia seen in the adult population. The abnormal rhythm originates in the right atrium causing it to beat irregularly. The ventricles will contract irregularly as well, although not as fast as the atria. When this occurs, patients may experience some chest discomfort, although many times it occurs asymptomatically. The pulse that is palpated in a patient with afib is termed irregularly, irregular. The electrocardiogram (ECG) of a patient with afib will show an irregularly, irregular rhythm. Afib has many possible causes; the most common are hypertension and coronary atherosclerosis. Any pathology that damages atrial tissue or causes atrial enlargement can lead to afib.

The main strategies to treating acute (new onset) afib with a rapid ventricular rate are: 1. Stabilization 2. Cardioversion. 3. Rate control. 4. Anticoagulation. The first step is to assess vital signs in a patient. If unstable, urgent cardioversion (electrical defibrillation synchronized with heart rhythm) to normal rhythm is indicated. The patient needs to be anticoagulated prior cardioversion if clots in the heart are seen in echocardiography. After cardioversion, the patient needs to be anticoagulated for several weeks afterward. Rapid heart rates can lead to hemodynamic instability (dangerously low or high blood pressures). Drugs such as beta-blockers, calcium channel blockers, and digoxin can be used to control heart rate. Once the patient is hemodynamically stable, evaluation can begin for underlying causes.

Patients whose afib cannot be cardioverted usually remain in chronic a fib. Their rate is controlled pharmacologically and they need to be assessed for long-term anticoagulation. The reason patients with afib need to be anticoagulated is that afib is a risk factor for stroke. Clots form in atria that fibrillate and these clots can dislodge and embolize to the brain, causing a stroke. For chronic afib, the overall chance of having a stroke is 5% per year, however, having more risk factors can increase risk. The scoring system used to assess anticoagulation is called the CHADS 2 score. Each patient gets one point for having congestive heart failure, hypertension, age greater than 75, diabetes, and two points for having a prior stroke. Patients who have a score of 0-1 are generally not anticoagulated but treated with low dose aspirin. Patients with a score of 2 or more are anticoagulated. Patients are anticoagulated with warfarin until their INR becomes between 2-3 (INR is a way of measuring the degree of anticoagulation). The major complication of warfarin therapy is bleeding as a consequence of elevated INR. Reducing the warfarin dose temporarily reduces the INR. If bleeding is severe, INR can be immediately reversed with intravenous vitamin K. Recently, a new drug called dabigatran is being evaluated as a replacement of warfarin for anticoagulation in patients with afib. The advantage dabigatran has over warfarin is that the INR does not need to be monitored, unlike warfarin. However, if a major bleeding event occurs, there is no way to reverse the anticoagulant effect of dabigatran like you can with warfarin using vitamin K. Dabigatran is also more expensive than warfarin. Please discuss with your licensed physician which anticoagulant is right for you.