Atrial Fibrillation versus Atrial Flutter – Coding Considerations

Today we are going to take a look at atrial fibrillation and atrial flutter: the difference between the two, the different types, and how to code them. 

First, there’s what is the same – atrial fibrillation and atrial flutter are both arrhythmias of the heart that originate in the atria. Both conditions may also share some of the same etiologies and symptoms. 

According to cardiovasculardiseasehub, atrial fibrillation is more complex, with a more irregular rhythm than atrial flutter. This is due to the electrical signals in the atria becoming disorganized, which is what makes the atria “fibrillate” or quiver, instead of contracting as normal. This then leads to that irregular rhythm noted in atrial fibrillation. In atrial flutter, on the other hand, the atria beats very rapidly, but in a regular pattern. An electrocardiogram can show differences as well. In atrial flutter, the ECG shows P waves in a “sawtooth” pattern. In atrial fibrillation, an irregular rhythm is noted, without those P waves identified.  

Atrial fibrillation and flutter share common etiologies of hypertension, coronary artery disease, heart failure, and valvular heart disease. “AFib,” as it is commonly called, can also be due to hyperthyroidism and sleep apnea, and is more common in those over 65; the incidence increases with age. A flutter can also be seen in patients who have had a previous heart surgery. Both conditions share common symptoms of palpitations, fatigue, dizziness, shortness of breath and chest discomfort. Both conditions also raise the patient’s risk of a stroke, but the risk is greater with atrial fibrillation due to the nature of the electrical impulses and the higher likelihood of blood stasis in the atria. 

According to WebMD, paroxysmal atrial fibrillation occurs when the heartbeat returns to normal within seven days, either with or without treatment. We would assign I48.0 for paroxysmal AFib. Persistent AFib lasts longer than a week and would be coded to I48.19. If the persistent AFib is documented to be longstanding, it has lasted more than a year and has not resolved. Longstanding, persistent AFib would be coded to I48.11. We also do have some Coding Clinic guidance on atrial fibrillation I would encourage you to review. The edition published for the second quarter of 2019 instructs us that when there are various types of AFib documented, we should only assign one code for the specific type of AFib, since some of the terms are less specific and some of the types can’t clinically occur together. It also notes that permanent AFib is persistent or longstanding when cardioversion as a treatment is not indicated or can’t be performed. Permanent AFib would be coded to I48.21. 

In coding atrial flutter, we can assign I48.92 for unspecified atrial flutter in addition to options for typical or type 1 atrial flutter and atypical or type 2 atrial flutter. According to WebMD, typical atrial flutter is more common (as the name would suggest). This type also involves the tricuspid valve and causes abnormal electrical signals in the right atrium. Typical atrial flutter would be assigned to I48.3. Atypical atrial flutter can occur in either the right or the left atrium, and it does not involve the tricuspid valve. Atypical atrial flutter would be assigned to I48.4. WebMD does note that atrial flutter that comes and goes could be referred to as paroxysmal atrial flutter, and flutter that continues for a longer period of time could be considered persistent atrial flutter. We do not have codes for this specificity…yet.