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How Is AFib Diagnosed?

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Find out more about diagnosing AFib in this video.

How is AFib diagnosed? For people who have not been diagnosed with atrial fibrillation, some may experience sudden onset of a racing heart or palpitations or just feel funny heartbeats in your chest. You may be wondering if you have atrial fibrillation or just as important, how do you figure out if it is atrial fibrillation or possibly something else? Here I will discuss the common ways atrial fibrillation is diagnosed so that you can make better sense of your symptoms.

How Does A Doctor Diagnose AFib?

There are several ways in which your doctor can diagnose atrial fibrillation. They may diagnose it during a physical exam, with an electrocardiogram (also known as ECG or EKG), or with an echocardiogram. Overall, the gold standard for identifying atrial fibrillation is a 12-lead EKG, which is commonly performed inside of a doctor’s office, as well as any medical facilities, such as at emergency room or hospital. In a 12-lead EKG, you’ll get 12 electrodes put on your body. Some of them will be on your chest and some of them will be on your arms and your legs. These electrodes will then be connected to a machine, which then will be able to record your heart’s electrical signals from 12 different angles. Usually, this recording only takes 30 seconds to do and the whole entire process usually only takes a few minutes.

How To Diagnose Atrial Fibrillation On ECG

The electrocardiogram, or ECG or EKG, is the gold standard for determining if someone has atrial fibrillation because it looks at the heart from so many different angles and it’s been used for over 100 years. In a normal EKG, there is a regular sequence of heartbeats, meaning that the interval between the heartbeats is usually fairly steady. In addition, there’s a small bump in front of every heartbeat, which is called the P wave. That is the unison contraction of the normal atrium, which are the upper chambers of your heart.

In contrast, in an EKG during atrial fibrillation, the P wave is usually absent. The atrium, the upper chambers of your heart, are all beating very chaotic and irregular and it’s usually represented by a fine squiggly line at the very bottom of the EKG strip. In addition, the actual heartbeats themselves are usually very irregular, there is no steady heartbeat. Sometimes the heartbeats can be rapid, but that is not always the case.

The tricky thing about an ECG is that in order to diagnose atrial fibrillation, you need to be in atrial fibrillation at the time the test is being done. A 12-lead ECG can only determine what is happening at the moment that the test is done, but for many people, especially at the earlier stages of atrial fibrillation, their symptoms may come and go and you may not be an atrial fibrillation all the time. This earlier stage is called paroxysmal atrial fibrillation. In addition, people may go prolonged periods of time between episodes. The frequency of episodes may be every week or it may be months between episodes. If your symptoms are infrequent, how is atrial fibrillation diagnosed?

Holter Monitor

What are alternative options for diagnosing atrial fibrillation? There are multiple at-home monitors that can be prescribed at your doctor’s office. The first one would be a 24 hour Holter monitor. A 24 hour monitor usually involves three or four electrodes on your chest, or sometimes a patch, that is then put onto your skin and records your entire heartbeat rhythm for an entire 24 hours. Then your doctor will get a complete analysis of that 24 hours to see if you are normal rhythm the whole time versus any episodes of atrial fibrillation, as well as the duration of any atrial fibrillation episodes. In addition, the Holter monitor will record any other abnormal heart rhythms that are not atrial fibrillation.

Event Monitor and Mobile Telemetry Monitor

However, patients may go prolonged periods of time without any episodes of atrial fibrillation, sometimes weeks or months. In these situations, how can a doctor best determine if you’re having intermittent episodes of atrial fibrillation? Other types of heart monitors that can be prescribed through your doctor’s office include event monitors and telemetry monitors. These are monitors that are can be worn for longer periods of time, anywhere from one week or up to one month.

These monitors are worn underneath your clothes and usually convenient. These monitors may involve a few electrodes under your clothes or a patch on your chest. Patients can still take showers and you take the monitors off and then put them back on again. In addition, these types of monitors allow you to record events. Thus, if you’re feeling some symptoms or palpitations, you can usually press a symptom button on the monitor and record symptoms so that your doctor can better interpret what is happening with your heart’s rhythm at the time of the symptoms that you are experiencing.

A mobile telemetry monitor, is more thorough then an event monitor, as it usually has continuous recordings of the heart rhythm for several weeks at a time, which can be very convenient and gives a lot of thorough data for your heart rhythm. However, it is more expensive than an event monitor and some insurance policies may not approve a telemetry monitor without at least trying a cheaper event monitor first.

Implantable Cardiac Monitors

Implantable loop recorders are small recording devices that go underneath your skin. These are implanted underneath your skin in a procedure that typically only lasts a few minutes. The size of the monitor is similar to a regular sized paperclip, but slightly thicker. The usual battery life of a loop recorder is 3 years, although it may not be necessary to have the monitor implanted for the entire duration of the 3 years of battery life.

Implantable cardiac loop recorder monitors can be excellent options for people who experience sudden symptoms or whom require continuous monitoring of their heart rhythm, such as due to atrial fibrillation.

To read more about implantable loop recorder monitors, read my article on loop recorders here.

Can AFib Be Detected By Echocardiogram?

An echocardiogram, also called ECHO, is an ultrasound picture of the heart, which a very common test performed in a cardiologist office. An echocardiogram is not as sensitive as the above tests for diagnosing AFIb, however, there are usually a few ECG electrodes placed during an echocardiogram. Since it has a few electrodes, it may provide some basic diagnostic information for AFib. However, the biggest benefit of an echocardiogram when it comes to AFIb are to determine causes of AFib. An ECHO will evaluate the function of the heart valves, as a leaky mitral valve is a common cause of atrial fibrillation. In addition a weakening heart function, called congestive heart failure or CHF, can also cause atrial fibrillation. An ECHO typically gives a clear picture of the overall heart function. Lastly, the ECHO can evaluate the size of the atrium, the upper chambers of the heart where AFIb comes from.  This evaluation gives a good picture of the long-term effects of AFib. The long-term effects of atrial fibrillation on the atrium is to become bigger and more dilated. In general, the longer someone has had atrial fibrillation, the more dilated the atrium will be.

How Can I Check for AFib At Home?

Despite many tests performed in a doctors office, many times a patient may still go undiagnosed. Sometimes people may have symptoms that are weeks apart or even months apart from each other. Patients may wear an event monitor or telemetry monitor for several weeks at a time and experience no symptoms, and then the moment the monitor is over then they start developing symptoms afterwards. Fortunately, these days there are an abundance of monitors at home that you can purchase and keep at home which are yours to keep that you can use whenever you’re experiencing symptoms.

KardiaMobile, KardiaMobile 6L, and Apple Watch

The top at home monitors for AFib are the KardiaMobile, KardiaMobile 6L, and the Apple Watch. The KardiaMobile was first developed several years ago and now last year, the company released the upgraded KardiaMobile 6L, which sees your heart at six different angles, which is more thorough than the original single lead version. Another commonly used option for at home monitoring of AFib is an Apple watch, which also can detect AFIb through a single lead ECG. The nice part about an Apple watch is that you’re wearing it all the time and you may be able to set up alerts for high heart rates, when the device detects a high heart rate you would then be able to initiate an EKG to see if you’re having episodes of atrial fibrillation.

Overall, my preferred device for at home monitoring for atrial fibrillation or to help your diagnosis is the KardiaMobile 6L because of the clear traces that it provides and the ability to be able to better diagnose what’s happening in your heart due to the fact that it shows the heart rhythm through multiple angles. Read my review of the KardiaMobile 6L here.

Silent AFib – Can You Have AFib and Not Know it?

Lastly, what if someone does not have any symptoms? It’s not uncommon that a patient gets diagnosed with atrial fibrillation accidentally. Sometimes patients are just going for a routine visit with their doctor or undergoing a routine procedure, such as a screening colonoscopy and their heart rhythm was found to have atrial fibrillation.

Another way silent AFib may be detected is through a pacemaker. Patients usually require pacemakers for symptomatic slow rates. However, aside from the pacemaker function to speed up a slow heart to a normal rate, a pacemaker is also a recorder. It is always recording and can frequently detect episodes of atrial fibrillation while the patient is asymptomatic. In these settings no matter how it gets diagnosed, getting a proper diagnosis will lead to proper evaluation and treatment.

In conclusion, there are many methods that can be used to diagnose atrial fibrillation. The most important tip is that it these tests can only detect AFib while a patient is having an episode. The fact that episodes frequently come and go is a common reason why atrial fibrillation may go undiagnosed. Fortunately, at home monitors like the KardiaMobile 6L are helping to fill in the gap of diagnosis that were left unmet by traditional heart monitors and ECGs. If you continue to feel symptoms that may be AFib, and there has been no diagnosis made during traditional testing, then discuss with your doctor if an at home monitor can help diagnose your symptoms.



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