Atrial Fibrillation (A Fib) affects 2.3 million adults in USA and is one of the most common arrhythmias. A Fib is an abnormal, rapid, heart rate that can present as palpitations, weakness and shortness of breath. A Fib increases your risk stroke as it may cause an atrial thrombus to form. In addition, A Fib can decrease your cardiac output which can cause heart failure. The goal of treating A Fib is to control your heart rate, either with drugs or with cardioconversion, and prevent thromboembolism via anticoagulation drugs.
Various diseases increase your risk of developing A Fib. Such conditions include hypertension, hyperthyroidism, coronary artery disease, valvular disorders, cardiomyopathy, or binge alcohol drinking (aka. Holiday heart).
Signs and Symptoms of Atrial Fibrillation
Many patients present with palpitations, chest discomfort, weakness, shortness of breath, or light-headedness. Some patients may have similar symptoms as those of a stroke or organ damage. Some patients may not experience any symptoms during A Fib. To confirm a diagnosis of A Fib, your doctor will need to order an ECG (electrocardiograph) which will show abnormal waves, intervals, and rhythm. Ecocardiographs and thyroid function tests are often ordered as well to assess the heart structure and identify additional risk factors for stroke.
Treatment of Atrial Fibrillation
After managing the cause of A Fib, treatment of A Fib has 3 key components: rate control, rhythm control, and prevention of embolism. The first decision made during the treatment of A Fib is whether to pursue rate control or rhythm control. Rate control is preferred for elderly patients who are asymptomatic or have minimal symptoms. Rhythm control is preferred for patients who have more than minimal symptoms, in young patients, or patients who have cardiomyopathy.
Patients with A Fib are at increased risk of developing cardiomyopathy due to tachycardia. For this reason, rate control tries to limit the heart rate to <100 beats/minute while resting. To achieve this goal, antiarrhythmic drugs are used. Beta-blockers (ex. Acebutolol, atenolol, betaxolol, bisoprolol, carvedilol, metoprolol, nadolol, propranolol, timolol) are preferred in thyroid disorders or with exercise-triggered cases. Nondihydropyridine calcium channel blockers (ex. Verapamil, diltiazem) can also be used. Digoxin is least effective at managing heart rate by is preferred if patient also has heart failure. Amiodarone can be added to combination therapy if the previous medication alone are not enough to manage heart rate. However, amiodarone is poorly tolerated and up to 18% of patients eventually discontinue their therapy due to side effects.
Rhythm control can be achieved through medication or with catheter ablation. Various antiarrhythmic drugs can be used such as procainamide, disopyramide, quinidine, propafenone, flecainide, amiodarone, dronedarone, sotalol, and ibutilide. All of the choices are about 50-60% effective in patients but have different side effects. Oral formulation of these drugs are used long-term for maintenance of sinus rhythm. After conversion to regular sinus rhythm, chronic anticoagulation is recommended
Long term Management of A Fib and Prevention of thromboembolism
In addition to chronic medication required to maintain rate or rhythm control, oral anticoagulants is recommended for prevention of stroke. Guidelines on how to approach anticoagulation therapy differ in each region and depending on your risk, your doctor may recommend aspirin alone or even no therapy. Warfarin and ASA have long been used as anticoagulants for this purpose and studies show that warfarin is more effective than ASA in prevention of stroke. Newer agents, such as apixaban, dabigatran, edoxaban, and rivaroxaban, are also commonly used as they require less monitoring and lifestyle changes. Various studies have shown that these newer agents are more effective than warfarin or ASA alone and are preferred except in special cases.
If you experience infrequent episodes of certain types of tachycardia, your doctor may recommend a “pill in pocket” approach to self administer a single dose of medication to restore normal heart rhythm.