Derek Burnett
Derek Burnett is a Contributing Writer at Bottom Line Personal, where he writes frequently on health and wellness. He is also a contributing editor with Reader’s Digest magazine.
Atrial fibrillation, also known as “A-fib,” is a type of heart arrhythmia in which the electrical signals that regulate contractions of the heart muscles are chaotic, resulting in a rapid, uneven, and inefficient heartbeat. The name “atrial fibrillation” refers to the upper chambers of the heart, or “atria,” which “fibrillate,” or quiver, during an A-fib episode.
If you’ve also heard of the term “atrial flutter,” you may have assumed that it was just another name for atrial fibrillation. In fact, these are two separate conditions which, while similar, have some important differences.
One of the main results of atrial fibrillation is an exaggeratedly rapid heartbeat of between 100 and 175 beats per minute. But the beating of a heart in atrial fibrillation is not just fast…it’s also ragged. When irregular electrical impulses hit the atria, their walls begin quivering, but not in an even-paced, steady way. A healthy heartbeat requires perfect timing between the contraction of the walls of the atria and, after a miniscule pause, that of the heart’s lower chambers, known as the ventricles. With atrial fibrillation, the different chambers of the heart no longer contract in precise alternation like a finely calibrated machine. Just like a combustion engine whose pistons aren’t firing in a coordinated way, the heart becomes inefficient. With its ability to pump compromised, it allows blood to pool in its chambers. This blood may clot and then travel to the brain, causing a stroke.
Just as with A-fib, atrial flutter is a heart arrhythmia caused by a faulty electrical signal. But it differs from atrial fibrillation in several ways. First, the faulty electrical signaling in atrial flutter is not chaotic and disorganized…rather, it is simply too rapid. This means that the atria are contracting too quickly, but not erratically as they are in atrial fibrillation. In a heart with atrial flutter, the atria contract so fast that only every second contraction is matched to the contracting action of the ventricles. A person with atrial flutter will have a pulse rate of about 150 beats per minute. While this is similar to the heart rate of someone whose heart is in atrial fibrillation, the A-fib patient’s ECG graph will appear highly irregular, while that of a person with atrial flutter will follow a uniform saw-toothed pattern.
There is considerable overlap in symptoms between atrial flutter and atrial fibrillation. With both conditions, people may experience an increased heart rate, fatigue, shortness of breath, dizziness, pounding in the chest, weakness, fainting, and chest pain. However, people with atrial fibrillation feel these symptoms more intensely than those with atrial flutter.
Important….It should also be noted that people who experience atrial fibrillation and atrial flutter may experience mild symptoms or none at all.
Atrial fibrillation and atrial flutter are associated with many of the same risk factors. These include high blood pressure (hypertension), heart disease, diabetes, alcohol use disorders, sleep apnea, heart-valve problems, heart failure, history of heart attack, and chronic lung disease.
Whether someone has atrial flutter or atrial fibrillation, they will work with their doctors toward similar goals…reducing stroke risk by preventing the formation of blood clots, and getting the heart’s rate, and if necessary its rhythm, under control.
Stroke-risk reduction is accomplished by taking anticoagulant medications, otherwise known as “blood thinners”. In recent years, a class of anticoagulants known as novel oral anticoagulants (NOACs, or non-vitamin-K oral anticoagulants) has eclipsed warfarin, which has historically been the primary treatment. Common NOACs include dabigatran, rivaroxaban, apixaban, and edoxaban.
To restore a regular heart rate, people often take a beta-blocker drug (such as diltiazem or metoprolol), or a calcium-channel blocker medication (such as diltiazem or verapamil). When doctors wish to regulate the heart’s rhythm, they may prescribe a class of drugs known as antiarrhythmics or cardiac dysrhythmia medications. These include propafenone, flecainide (Tambocor), and amiodarone (Cordarone).
Whether they have atrial flutter or atrial fibrillation, people may undergo similar procedures to correct the electrical signaling in the heart. These include cardioversion, in which the heart is paused and then restarted, which often restores normal electrical activity…catheter ablation, which uses extreme heat or cold to destroy heart tissue in the atrium where abnormal electrical activity is centered…maze surgery, in which a similar end is achieved by intentionally cutting or burning the atrium…and AV node ablation, in which the cluster of cells that serves as the electrical connection between the upper and lower chambers of the heart is destroyed and replaced with a pacemaker.
Atrial fibrillation is more common than atrial flutter, and people with A-fib have a stroke risk five times higher than that of the general population. Atrial-flutter patients still have elevated risk of stroke, but it is significantly lower than that of atrial-fibrillation patients. In a study led by researchers at Weill Cornell Medicine, 1.38% of patients with atrial flutter suffered an ischemic stroke within a year, compared to 2.02% of patients with atrial fibrillation.
There is also a danger that atrial flutter will convert to atrial fibrillation. Atrial flutter is known to be a risk factor for A-fib, and the same Weill Cornell Medicine study found that more than 65% of flutter patients went on to develop atrial fibrillation within one year. Fortunately, the stroke risk of those people whose flutter converted to A-fib remained lower than that of the those who had had fibrillation at the study’s outset.
