Atrial Flutter Ablation
How do abnormal heart rhythms occur?
In some hearts, an abnormal heart rhythm develops when an electrical impulse starts from a different location, other than the SA node, or follows a route (or pathway) that is not normally present. This is what happens in atrial flutter. A short-circuit develops in the right atrium.
A single abnormal electrical short-circuit originates from the right atrium. Atrial flutter is due to a short circuit in one of the upper chambers of your heart termed the right atrium. This rapid short circuit has several consequences:
The short circuit drives the pumping chambers very rapidly and sometimes erratically. This produces palpitations, shortness of breath and tiredness. In some people it can also cause dizziness and chest pain.
The short circuit results in ineffective pumping of the upper chambers. This leads to slow blood flow in both of these upper chambers (the left and right atrium). This can rarely cause blood clots and possibly stroke. One of the major reasons to cure atrial flutter is to prevent this risk of stroke.
WHAT TREATMENTS ARE AVAILABLE FOR ATRIAL FLUTTER?
Atrial flutter can be treated with medication. In some people these medications can be very effective. In others however, the medications are ineffective and may produce side effects. If you elect to take medication, your doctor will discuss the different options and the possible side effects of these medications.
DC Shock. When the heart is in flutter it can be reverted to the normal rhythm with a “shock on the chest”. You receive a short general anaesthetic and the shock reverts the rhythm to normal in almost all cases. With this approach the possibility of the flutter returning remains present (approximately 50% of patients will have another episode of atrial flutter over the next year). In addition, most patients will also require medicine to try to prevent the flutter coming back.
Blood Thinning medication. Because of the risk that atrial flutter may return with the above treatments, most patients with atrial flutter will require blood-thinning medication to prevent blood clots forming. At your doctors’ discretion this may either be aspirin or warfarin.
Radiofrequency ablation. This procedure carries a success rate of approximately 95% for curing the atrial flutter. The risk of the flutter returning at some time in the future is approximately 5%.
WHAT IS RADIOFREQUENCY ABLATION (RFA)?
Radiofrequency is a low power, high frequency energy that causes a tiny region of the heart, near the tip of the catheter to increase in temperature, thus ablating (or cauterising) a small area of abnormal tissue. Radiofrequency energy has been used for decades by surgeons to cut tissue or to stop bleeding. For the treatment of palpitations, a much lower power of radio-frequency energy is used.
WHAT HAPPENS DURING A RADIOFREQUENCY ABLATION PROCEDURE?
You will usually be admitted to hospital on the day of your procedure. You will be required to fast for at least six hours before the study. Prior to the procedure you will require an ECG. Once in the Electrophysiology Laboratory (EP lab) you will be given a light sedative and your groin will be shaved. The EP lab has a patient table, X-Ray tube, ECG monitors and various equipment. The staff in the lab will all be dressed in hospital theatre clothes. Many ECG monitoring electrodes will be attached to your chest area and patches to your chest and back. These patches may momentarily feel cool on your skin.
A nurse or doctor will insert an intravenous line usually into the back of your hand. This is needed as a reliable way to give you medications during the study without further injections. You will also be given further sedation if and as required. You will also have a blood-pressure cuff attached to your arm that will automatically inflate at various times throughout the procedure. The oxygen level of your blood will also be measured during the EP study and a small plastic device will be fitted on your finger for this purpose.
Your groin area and possibly your neck will be washed with an antiseptic cleansing liquid and you will be covered with sterile sheets leaving these areas exposed.
The procedure may be performed under local anaesthetic with sedative medication or occasionally under full general anaesthetic. This will be discussed with you before the procedure. If the procedure is performed under local anaesthetic, the doctor will inject the anaesthetic to the area in the groin where the catheters are to be placed. After that, you may feel pressure as the doctor inserts the catheters but you should not feel pain. If there is any discomfort you should tell the nursing staff so that more local anaesthetic and sedative medication can be given. Occasionally it is also necessary to place a catheter in a vein in the side of the neck.
The catheters are positioned in your heart using X-Ray guidance. Once the catheters are in place you may feel your heart being stimulated and usually your abnormal heart rhythm will be induced. When the type of abnormal rhythm has been identified and the abnormal tissue localised, the radiofrequency ablation will be applied to this spot. The short-circuit is localised electrically and a small burn created at the weak-link in the short circuit. This may cause a transient warm discomfort in the chest. The atrial flutter ablation procedure may take approximately 2-3 hours on average.
WHAT ARE THE RISKS OF AN ATRIAL FLUTTER ABLATION PROCEDURE?
The Radiofrequency ablation procedure is a very low-risk procedure and should a complication arise, it will be dealt with immediately. The worldwide complication rate for Electrophysiology studies and radiofrequency ablation procedures is less than 0.5%. Although most people undergoing radiofrequency ablation procedures do not experience any complications, you should be aware of the following risks:
Local bleeding, blood clot or haematoma (blood collection) – this may occur at the catheter insertion site.
Rapid abnormal heart rhythm – this may actually cause you to pass out for a very short period of time and in some cases a small electric shock may be required to restore your normal rhythm. A proportion of patients with atrial flutter go on to develop another related arrhythmia called atrial fibrillation. Atrial fibrillation has similar consequences to atrial flutter but its treatment can be more difficult. You will need to be reviewed regularly to ensure you do not develop this condition.
Perforation or damage – very slight chance that this may occur to either a heart chamber or to the wall of one of the arteries.
Heart block – depending on the location and type of your atrial flutter, there is a very small chance of damage occurring to the heart’s normal electrical system. This may be temporary, but permanent damage would result in a pacemaker being inserted at the time of the procedure.
Major complications – stroke, heart attack, and death are very rare.
WHAT SPECIAL PRECAUTIONS WILL BE TAKEN?
As discussed above, atrial flutter carries a very small risk of stroke due to the risk of blood clot formation in the left atrium. This is one of the reasons to cure the rhythm disturbance. This risk increases slightly at the time that the heart reverts from the atrial flutter to the normal rhythm. This increased risk is present whether the rhythm is reverted with medication, with a DC shock on the chest or with a radiofrequency ablation procedure. In order to prevent this occurring the following precautions will be taken:
In the week prior to the procedure or at the time of the procedure you will have a special ultrasound study of your heart called a transoesphageal echo. This involves passing a small probe into the oesophagus (the swallowing tube) to give clear pictures of the heart and ensures that no blood clots are present.
During the procedure you will be given blood-thinning medication.
After the procedure you will be started back on blood thinning medication (warfarin) for 6 weeks. The warfarin may take approximately 1 week to reach the required levels and during this time you will also be receiving daily injections of clexane. You will be shown how to administer these.
If there is any chance you may be pregnant, please notify the Cardiovascular Centre and the hospital before your procedure. The procedure is associated with additional risks if you are pregnant.