It’s a Fib

By Peter Galvin, MD

Atrial fibrillation (AF) is a common electrical disorder of the heart in which the heart’s upper chamber, the atrium, quivers or fibrillates instead of contracting and beating. In the U.S., it affects about 10.55 million people and is more common in men. AF is classified as paroxysmal (intermittent episodes lasting seven days or less), persistent (lasting more than seven days), longstanding persistent (lasting more than one year), or permanent. Risk factors include older age, smoking, high blood pressure, diabetes, heart disease, high alcohol consumption, sleep apnea, an overactive thyroid gland, and possibly genetic factors.

Typical symptoms include heart palpitations, trouble breathing, chest pain, feeling faint, difficulty with exercising, and fatigue. However, about 10% to 40% of those with AF have no symptoms. AF can be diagnosed by a physical examination and an EKG. For those with suspected AF that is not shown on an EKG, they may use a wearable device like a smart watch to detect it. They may also choose to use a portable home device with two finger pads to check their heart rhythm. Or an implantable device called a loop recorder can be used. This device can record the heart’s rhythm for up to four years.

Sometimes AF is diagnosed after the patient has an unexplained stroke. Stroke is a main concern in AF because the atrium is shaped like a pyramid. When in fibrillation, clots may form in the corners of the atrium and are pushed out into the bloodstream once the heart returns to a normal rhythm and the atrium resumes beating. This is why those who have paroxysmal, or intermittent, AF are at the highest risk for stroke. The stroke risk for those in permanent AF is much lower. Once AF is diagnosed, an ultrasound of the heart, or echocardiogram is performed to examine the structure of the heart and look for causes of AF such as a damaged or leaking valve. Also, those diagnosed with AF often can lower their risk of recurrent AF by lifestyle modifications such as weight loss, smoking and alcohol cessation, and moderate exercise.

Based on risk score calculators, those with AF who are predicted to have a 2% or higher risk of stroke are usually treated with an oral blood-thinning drug such as a direct-acting anticoagulant ([DAC] apixaban, dabigatran, edoxaban, or rivaroxaban) or warfarin (Coumadin). Warfarin use requires periodic blood testing; DACs do not need any testing. Restoring a normal heart rhythm can be done using oral medications or electrical cardioversion, which involves sending a mild timed electrical shock to the heart with external patches or paddles (usually requires anesthesia). Catheter ablation is an invasive procedure that delivers cold energy or heat to the heart tissue that is causing the AF (this abnormal tissue is often found just outside the heart in the pulmonary vein). There is a small risk that following catheter ablation, the patient may require a pacemaker. For those with AF and heart failure with a reduced ejection fraction (the heart does not pump blood effectively), catheter ablation may improve symptoms, quality of life, heart function, and cardiovascular outcomes.

For more information, go to the website of the National Heart, Lung, and Blood Institute at www.nih.gov

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