Patients with atrial fibrillation or Afib have a five-fold increased risk of stroke, mostly caused by blood clots. In order to lower the risk of blood clots, physicians often prescribe blood thinners such as aspirin and clopidogrel (Plavix) and anticoagulants such as warfarin (Coumadin), rivaroxaban (Xarelto), and dabigatran (Pradaxa). Anticoagulants can also be used to control heart rate and heart rhythm.
Controlling Heart Rate
If the goal of pharmacological therapy is to slow down a rapid heart rate, beta-blockers and calcium channel blockers are typically used. Examples of beta blockers include propranolol (Inderal), atenolol (Tenormin), metoprolol (Lopressor), and esmolol (Brevibloc). Examples of calcium channel blockers include verapamil (Calan) and diliazem (Cardizem). These medications slow the heart rate by slowing the rate of electrical conduction throughout the heart, but they typically do not cause the heart to beat with a normal rhythm.
Controlling Heart Rhythm
Rather than control the patient’s heart rate, a physician may decide that controlling the patient’s heart rhythm is more appropriate. An approach aimed at converting Afib to a normal heart rhythm (also known as normal sinus rhythm) is more likely to be utilized in younger patients, patients whose heart chambers are not enlarged, and patients with paroxysmal atrial fibrillation. In these instances, antiarrhythmic drugs are used. The most commonly prescribed antiarrhythmic agents include quinidine, propafenone, dofetilide, sotalol (Betapace), flecainide (Tambocor) and amiodarone (Cordarone).
Medications used to treat Afib are not without side effects, and in some cases require periodic monitoring. For example, patients taking warfarin must have their blood tested on a regular basis, usually once or twice a month. Side effects for other commonly prescribed drugs include:
- Beta-blockers: fatigue, low blood pressure, and coldness of hands and feet
- Verapamil: low blood pressure, ankle swelling, and heart failure
- Flecainide: nausea, vomiting and heart rhythm disorders
- Amiodarone: sensitivity to sunlight, changes to liver or thyroid function and lung problems