What's the treatment for atrial flutter?
For both atrial flutter and atrial fibrillation, the various treatment modalities can be put into two groups: rate control and rhythm control. While it was previously believed that it is "better" to have people in normal sinus rhythm (the normal rhythm of the heart) rather than in atrial fibrillation or flutter, the AFFIRM trial recently showed that there is no survival benefit of maintaining someone in normal sinus rhythm compared to atrial fibrillation or flutter. In general, atrial flutter should be
treated the same as atrial fibrillation. Both rhythms do not provide effective contraction of the atria. Because of this, there is stasis of blood in the atria. This stasis of blood leads to the potential formation of thrombus material in the atria. Therefore, individuals with atrial flutter require some form of anticoagulation or anti-platelet agent. In addition to the treatments available to individuals in atrial fibrillation, there are a couple treatment considerations that are particular to individuals with atrial flutter.
Ablation: Because of the reentrant nature of atrial flutter, it is possible to ablate the circuit that causes atrial flutter. This is done in the electrophysiology lab by causing a ridge of scar tissue that crosses the path of the circuit that causes atrial flutter. The abnormal pathway(s) is found, and a catheter is placed at this precise location in the conduction system. After proper placement, the catheter delivers radiofrequency energy, which burns ("ablates") a portion of the abnormal electrical conduction pathway. This inactivates the abnormal pathway to provide more consistent flow of electrical impulses. This technique is very safe; it works in some people but not all. When it does work, atrial flutter is permanently cured. It has few complications and, unlike surgery, requires little recovery time.
Rate control: Control of the ventricular rate in atrial flutter may be more difficult than if the individual was in atrial fibrillation. This is because of properties of the AV node. In atrial fibrillation, the AV node is typically bombarded with signals from the atria at rates in excess of 400 beats/minute. This causes a high degree of block within the AV node, with many signals partially penetrating the node and blocking at the lower levels of the AV node. This phenomenon is known as concealed conduction. In atrial flutter, on the other hand, the AV node receives signals very rhythmically at a rate of about 300/minute. Since the atrial flutter is an organized rhythm of the atria, the block at the AV node will be consistently at the same level, and paradoxically a higher number of impulses will get through per minute. Because of this, it may be easier to control the rate of some individuals if they are converted from atrial flutter to atrial fibrillation. While there are no guidelines for this procedure at this time, this may be attempted in the electrophysiology lab by pacing the atria at rates well over 300 beats/minute.
Medications: The choice of medication depends on the frequency of atrial flutter you have, the underlying cause, your other medical conditions and overall health, and the other medications you take. Anti-arrhythmic medications are used to chemically convert atrial flutter to normal sinus rhythm, reduce the frequency and duration of atrial flutter episodes, and prevent future episodes. They are often given to prevent return of atrial flutter after cardioversion. Examples are amiodarone, sotalol, ibutilide, propafenone, and flecainide. Digoxin (Lanoxin) decreases the conductivity of electrical impulses through the SA and AV nodes, slowing down the heart rate. Beta-blockers decrease the heart rate by slowing conduction through the AV node, plus they have a direct anti-arrhythmic effect on the atria. Calcium channel blockers also slow down the heart rate by slowing conduction through the AV node. Anticoagulants reduce the ability of the blood to clot, thus reducing the risk of an unwanted blood clot forming in the heart or in a blood vessel. Atrial flutter increases the risk of forming such blood clots.