Atrial Fibrillation: The Rhythm Is Gonna Get You

Cue Gloria Estefan.

It’s safe to say that we trust our hearts to beat rhythmically, predictably, and regularly. When I put the stethoscope to your heart during a physical exam, I listen for several things. Is the heart beating regularly with a steady pattern (rhythm)? Is it beating slowly, quickly, or normally (rate)? Are there abnormal sounds (murmurs, for instance)? All of these indicate if you have issues with the electrical activity of the heart or the structure of the heart, for instance. 

It’s safe to say that most of you have felt your heart “beat out of your chest” or “skip a beat” when you’re nervous, scared, or excited. Well, some folks have a condition called Atrial Fibrillation where the top half of the heart dances to the beat of its own drum with no regard to what the bottom half of the heart is doing. The rhythm of the heart is affected in this condition, thus atrial fibrillation is called an “irregularly irregular” heart rhythm. Tongue twister, I know.  Interestingly, patients who have this condition sometimes have no idea their heart is doing this and some can immediately tell the moment it goes out of rhythm. This particular fact has always baffled me—the difference in patient experiences and testimonials. I have caught AFib on a routine physical exam many times in the last 6 years where the patient has no idea their heart is beating abnormally (insert mind blown emoji).

Let’s back up and review basic anatomy of the heart (photo below). The northern half of the heart is made up of two chambers (left and right atria) and the southern half is made of the left and right ventricles. The heart is supposed to squeeze or “contract” in a rhythm, trading off between top half, bottom half, top half, bottom half, etc. The atria, when they contract, push blood down into the bottom chambers, called ventricles. Then when the ventricles contract, they push blood out of the heart (either to the lungs to get oxygen or to the rest of the body to deliver that oxygen). The muscles contract because the electric current tells them to. Anyway, atrial fibrillation is when those atria beat without that regular rhythm, and in other words, dance. 

The electricity of the heart is compartmentalized in different nodes (picture below). The sinoatrial (SA) node is at the top of the heart, and it’s the beginning of the heart’s electric cycle. Electric current beginning here travels downward to the atrioventricular (AV) node, near the middle of the heart. Downward it goes again and splits to the right and left bundles of His to deliver current to the bottom of each ventricle, ending in the small purkinje fibers. The issue with AFib is with that first node at the top, the SA node. It goes haywire and the atria do not synchronize like they’re supposed to with the ventricles, and they fibrillate.

We can both find and confirm that someone has atrial fibrillation with an EKG (electrocardiogram). This is the test where wires are stuck to your chest and to your limbs to detect what the electric activity of your heart is doing. We see certain patterns in the wave lines on that EKG (photo below shows a visual comparison between normal and AFib patterns). We also can catch atrial fibrillation on an echocardiogram, which uses ultrasound to watch the heart beat in real time. The cardiologist may also order a heart monitor to wear for several days to one month in order to track the frequency of the arrhythmia as well as how burdensome it is to the patient. This can give an extensive amount of data to help indicate whatever treatment pathway the patient will need to take.

There are different types of AFib. Some patients have the type that comes and goes, or “paroxysmal” AFib. It will come in episodes of a few minutes to a few hours or even days (no more than 7 days in length). The key to this type is that it resolves spontaneously without intervention. If the AFib lasts longer than 7 days, it’s considered “persistent.” At this point, an electrophysiologist (think the electrician of cardiologists) tries to reset the rhythm back to normal. We’ll go into the ways they attempt that in a minute.

Chronic AFib lasts for 12 months or longer. Calling someone a “permanent AFib” patient means it really doesn’t seem to subside after an extended period of time, and attempts are no longer made to fix the rhythm. Rather, the patient will be on certain medications to ensure stability of their vitals (heart rate and blood pressure) over time.

So, why is AFib important to know about? Men and women between the ages of 55-74 who have AFib have a 10-year mortality risk that’s double that of their peers without AFib (Sankaranarayanan et al, 2015). AFib, especially if untreated or undiagnosed, can lead to heart failure, stroke, quality of life reduction, and more. In fact, 15-25% of all strokes are due to AFib. It’s the most common sustained cardiac arrhythmia we see, and over 2.2 million Americans suffer from it.

So you’re told you have AFib…what happens next? First we prescribe you a blood thinner, AKA an anticoagulant. You’ll take something like warfarin (one common name is Coumadin), or one of the newer and, in most clinicians’ opinion, better agents— their common names are Eliquis, Xarelto, Pradaxa, etc. The reason we immediately prescribe you a blood thinner is — when your heart has an unpredictable rhythm, blood can pool in the chambers of the heart for a few seconds. Blood is meant to be constantly moving through the chambers. If blood is stagnant anywhere in the body, it clots. A clot that forms in the heart can cause a stroke by traveling through the carotid arteries (in the neck) to the brain. Strokes are obviously something the average patient hopes to avoid, thus a blood thinner is indicated in patients with AFib. In fact, anticoagulants, when taken properly, reduce the patient’s risk of dying by 26%, and risk of stroke by 64% (Sankaranarayanan et al, 2015).

While we prescribe a blood thinner, we also prescribe something to help regulate your heart rate and rhythm. You may have heard of some– amiodorone and propafenone (Rhythmol) are two common ones, but there are many others. While writing these prescriptions, though, we also write a referral to an electrophysiologist (the cardiology electrician) to decide which method of management is needed. 

This specialized cardiologist can perform something called cardioversion. This is when they use an electric current to shock the heart back into a normal rhythm. Sometimes a patient’s heart goes back into the “irregularly irregular” rhythm despite this procedure, and medication is relied upon from that point to keep it as calm as possible the rest of that patient’s life. Cardioversion procedures aren’t for everyone with AFib. If the patient is generally asymptomatic and feels unbothered by their abnormal heart rhythm, and if their blood pressure and pulse stays reasonably stable, there isn’t much reason to put them through cardioversion. If you do get this *shocking* treatment, it’s over 90% effective to restore normal heart rhythm. Does it always stick? No, of course not! That would be too easy. But there exists a handful of effective oral medications to maintain a calm rate/rhythm if and when the procedure fails. It is also common for the cardiologist to start a medication prior to the attempted shock so as to make the procedure’s potential success higher. Ok, I know I’m getting detailed and probably making your eyes glaze over, so I’ll stop here with the cardioversion portion of the lecture. 

A newer and super cool procedure that AFib sufferers may qualify for is something called The Watchman. This is a device about the size of a quarter that is implanted into the left atrial appendage of the heart. This region of the heart is where most blood clots form due to AFib. Remember, clots lead to strokes. The Watchman device allows patients to stop their blood thinner medications about 6 weeks after the procedure (in 96% of patients). It’s a one-time procedure that lightens medication burden and the risks that come with blood thinning agents. 

If you read this post but find yourself a visual learner, I found a great 5 minute video explaining the basics of AFib. Thanks to Chicago St Vincent Hospitals for this visual synopsis. 

Now I must say, for the sake of brevity and simplification, I have left out many ifs, ands, and buts regarding the decision-making process for the management and treatment of AFib. So it goes without saying, please speak with your medical team if you feel you have experienced atrial fibrillation: ever or recently, or maybe sitting here reading! Some less severe phenomena like sinus tachycardia, premature atrial contractions, or premature ventricular contractions may feel the same as AFib to you, so if you feel uncomfortable palpitations regularly, especially if they are accompanied with dizziness, sweatiness, nausea, and a racing heart/high blood pressure, please make an appointment with your PCP or cardiologist soon. They can help you differentiate the diagnoses with the methods listed above.

I hope by reading this post, you close the page knowing a little more about this condition. I write about conditions like this because I hope to educate on medical diagnoses that can be detected and thus managed to help patients have an increased quality of life. Now, go dance; but let’s count on your heart staying in rhythm while your feet may or may not.

PS- you get bonus points if you have this album/cassette/CD.

References:

Kumar K. Antiarrhythmic drugs to maintain sinus rhythm in patients with atrial fibrillation: Recommendations. UpToDate. https://www.uptodate.com/contents/antiarrhythmic-drugs-to-maintain-sinus-rhythm-in-patients-with-atrial-fibrillation-recommendations?search=atrial%20fibrillation%20treatment&topicRef=1025&source=see_link.

Sankaranarayanan R, Kirkwood G, Visweswariah R, Fox DJ. How does Chronic Atrial Fibrillation Influence Mortality in the Modern Treatment Era?. Curr Cardiol Rev. 2015;11(3):190-198. doi:10.2174/1573403×10666140902143020

Watchman.com. Boston Scientific. https://www.watchman.com/en-us/alternative-to-blood-thinners.html.