How is atrial flutter treated?

You have had an unpleasant racing heart for hours, and dizziness and faintness are also worrying you, and the ECG done at your doctor's office or at ER shows that you have atrial flutter. The following treatments are then an option:

Doctors usually try to quickly put the heart back into its normal sinus rhythm, especially if the atrial flutter is causing severe circulation problems. This procedure is called cardioversion. Because it uses a burst of electrical energy, it is sometimes also called electrical cardioversion.

You will be given a short-lasting mild anesthetic for the electrical cardioversion. Electrodes that deliver the electrical energy are stuck or pressed onto your chest. This burst of electrical energy stimulates all of the heart muscle cells at once, and they then relax again at the same time. That gets rid of the signals circulating in the atrium that caused the atrial flutter and kept it going. The heart starts beating in its normal rhythm again on its own.

Electrical cardioversion is considered to be very effective and well tolerated, which is why it is the preferred treatment for acute atrial flutter. Side effects such as skin burns are rare. The anesthetic can also have side effects.

Using medication to slow down the fast heart rate is an alternative to cardioversion. The medication is injected intravenously to treat acute atrial flutter. This treatment is also called frequency control and is an option if your circulation is stable but you don’t want or can’t have electrical cardioversion, perhaps because you wouldn’t tolerate the anesthetic. Frequency control is sometimes used to bridge the gap until cardioversion can be carried out and to relieve symptoms like a racing heart (palpitations), dizziness and faintness. Beta blockers and calcium channel blockers are especially well suited for this.

But these medications don't stop the atrial flutter, so they don’t reduce the risk of stroke, either, especially if there are other risk factors like old age.

These medications are no longer needed if the heart's rhythm goes back to its normal sinus rhythm either on its own or with cardioversion and is kept there using catheter ablation. If that doesn't work, the medication can still be taken in tablet form over the long term. But this option is usually only recommended if the atrial flutter and high pulse don't have a major effect on your everyday life. The typical side effects of beta blockers may include breathing difficulties, low blood pressure and nausea. The possible side effects of calcium channel blockers include headaches, itching, skin rashes, nausea and other heart rhythm disorders.

If you already have a defibrillator or pacemaker, the heart’s normal rhythm can also be restored using the implanted device. It is then set to briefly stimulate the heart to an even higher frequency. This “overpacing” stops the atrial flutter. The heart can then continue beating normally again.

It is also theoretically possible to restore the heart’s normal rhythm with medication (cardioversion with medication). Only amiodarone is available for that in Germany. But its cardioversive effect is low, meaning that it can’t reliably restore the heart's normal rhythm. That is why amiodarone is usually only used to slow the heart rate down. Experts only recommend it if other treatment options haven't worked or weren't tolerated. Side effects include trembling, and problems affecting skin, vision, and circulation. Amiodarone can also cause heart rhythm disorders itself and lead to problems with the lungs, liver and thyroid. Pregnant women and people with an overactive thyroid or iodine allergy can't take it.

Like atrial fibrillation, atrial flutter can also cause blood clots to form in the atria. That can lead to a stroke or pulmonary embolism if the clots pass into the brain or the lungs. Anticoagulants, generally often referred to as blood thinners, can be taken to prevent that. But they increase the risk of bleeding, such as in the digestive tract (stomach and bowel). That is why these pros and cons need to be considered before starting the treatment.

People with atrial flutter and atrial fibrillation are given anticoagulants as recommended for treating atrial fibrillation. There are not many studies on the use of this treatment for atrial flutter alone, which is why there are fewer specific rules. So treatment with these medications is based on the procedure for atrial fibrillation and depends on your individual risk of stroke. For instance, experts recommend anticoagulants to treat atrial flutter if an ultrasound scan has detected blood clots in the atria before an electrical cardioversion procedure or if the atrial flutter has already lasted for longer than 48 hours.

Things like your individual risk of a stroke determined whether you need medication, and if so for how long. That risk is especially high if you are over 75 years old and have already had a stroke. High blood pressure, coronary artery disease, heart failure and diabetes are also risk factors. Women have a higher risk of stroke.

A small amount of heart tissue is usually cauterized within a few weeks of cardioversion to prevent atrial flutter in the long term. Doctors insert a thin tube called a catheter into a vein through an incision in the groin. They then push special instruments through the catheter up to the heart. The tissue there is heated up using electricity and then destroyed; in rare cases extreme cold is used instead. Experts call this procedure catheter ablation.

A local anesthetic in the groin and a short, mild anesthetic used while the tissue is being destroyed are typically enough. You will usually stay overnight at the hospital after the procedure. The possible risks are bleeding, stroke, heart rhythm disorders and damage to heart or other tissue. Overall, about 20 out of 1,000 people develop severe complications, and 2 out of 1,000 people die as a result of the procedure.

In typical atrial flutter, the area right between the inferior vena cava and the heart valve that connects the right atrium and the right ventricle is usually destroyed. Experts refer to that small piece of tissue as the cavotricuspid isthmus (CTI). In typical atrial flutter, the stimulating signal repeatedly circles that spot. That is no longer possible if that area is scarred after some of the tissue has been destroyed.

CTI ablation can effectively stop atrial flutter from returning in about 90 percent of people with typical atrial flutter. But atrial fibrillation, the other, more common heart disorder that occurs in the atrium, can still develop at a later stage.

There are also types of atrial flutter where the narrow part between the vena cava and the heart valve is not involved. That is referred to as atypical atrial flutter. Ablation can help here, too, but the chances of success are lower than for typical atrial flutter. This procedure is normally carried out in a specialist heart clinic. They can check where the abnormal signals are coming from before and during the procedure to work out which parts of the atria have to be destroyed.