What is an ablation?
Ablation is a procedure for restoring normal heart rhythm, particularly if the irregular rhythm has not responded to medication. Usually, the heart beats between 60 and 80 times a minute. The pumping action of your heart is triggered by electrical impulses. Ablation may be used to treat a heart that beats too quickly (more than 100 beats per minute, a condition known as tachycardia), or a heart that beats so it contracts in an uncoordinated fashion, known as fibrillation.
Why is it done?
Abnormal heart rhythms known as arrhythmias can cause:
- shortness of breath
The goal is to restore a regular rhythm to prevent these conditions from occurring.
What is done?
Many abnormally fast heart rhythms are triggered by areas of abnormal heart tissue that cause the electrical system of the heart to “short-circuit.” By ablating or destroying these areas, the scar tissue that forms helps to prevent this short-circuit and allows for a return to a normal regular heart rhythm. There are two main ways in which ablation can be performed: surgically or by catheter (nonsurgically).
Although less common, surgical ablation may be combined with other open-heart surgeries, such as bypass surgery or heart valve repair or replacement.
Surgical ablation is performed under general anesthetic – in other words, you will be asleep throughout the procedure. To reduce the risk of vomiting while asleep, you will be asked not to eat or drink after midnight the night before surgery. If you smoke, you should stop at least two weeks before your surgery, as smoking can contribute to blood clotting and breathing problems.
There are two main types of surgical ablation. Some procedures require that the heart be stopped and the patient be put on a heart-lung machine (referred to as “on-pump” ablation). Others can be performed on a beating heart and do not require the use of a heart-lung machine (“off-pump” ablation).
- Cox-Maze Procedure
Physicians will make a precise pattern of incisions (cuts) inside the upper chambers of the heart (the right and left atria). These incisions will then be sutured (sewn) together. This creates scar tissue that stops electrical activity from passing through the upper chambers. The heart must be stopped and a heart-lung machine used for the Cox-Maze Procedure. This procedure is also referred to as Atrial Fibrillation Ablation. Although there are various techniques, this is the most common technique for surgical ablation.
- Surgical Ablation
Newer technologies have been developed that make it possible to perform cardiac ablation without making incisions (cuts) inside the heart. A number of different approaches have been developed to destroy the areas of malfunctioning heart tissue, including radiofrequency (RF) waves, microwave, laser or freezing. One such new procedure called Minimally Invasive Cardiac Surgery for Atrial Fibrillation is now being conducted more often in Canada.
Catheter ablation is a non-surgical procedure that uses thin, flexible tubes called catheters to reach inside the heart. It does not require a general anesthetic or stopping the heart. This technique is used more commonly with newer technologies in large centres.
To perform the procedure, one or more catheters are inserted into the blood vessels and are threaded into the heart using a fluoroscope (a form of moving X-ray picture). Catheters referred to as diagnostic catheters will be used to study the abnormal heart rhythm and determine where the problem is located. Once the location of the abnormal heart tissue has been identified, a special ablation catheter will be positioned nearby. A tip on the ablation catheter will emit high-frequency electrical energy to destroy the abnormal tissue, resulting in a scar. The scar tissue is incapable of initiating the electrical signal causing the arrhythmia. In other words, it fixes the short-circuit.
What can you expect?
Usually, the procedure is scheduled ahead of time. A week or so before your procedure, you will probably be asked to visit your hospital’s pre-admission unit. Blood and urine tests, an electrocardiogram, and an X-ray may be performed. Your doctor will explain the risks and benefits of the procedure and you will be asked to sign a consent form. You may be asked whether you (or inform your doctor if you):
- Have ever had a reaction to any contrast dye, iodine, or any serious allergic reaction (for example, from a bee sting or from eating shellfish).
- Have asthma.
- Are allergic to any medication.
- Have any bleeding problems or are taking blood-thinning medication.
- Have a history of kidney problems or diabetes.
- Have body piercing on your chest or abdomen.
- Have had any recent change in your health.
- Are, or may be, pregnant.
Your recovery will depend upon the type of procedure you underwent (catheter or surgical procedure), and whether other surgery was performed at the same time.
When you return home, keep an eye on your incisions. Some bruising is normal but contact your doctor if you experience:
- increased pain
- bleeding or other draining from an incision
- fever or chills.
Some recurrence of the arrhythmia may be experienced, particularly during the first 2 or 3 weeks. Stable, normal rhythm is usually not achieved until 3 to 6 months after the procedure. Most people will probably be prescribed antiarrhythmic medications during this period to help the heart recover its normal rhythm.
Electrophysiology and Standard Ablation: A guide for patients and families (University of Ottawa Heart Institute)