Introduction to treating arrhythmias with ablation
Ablation is used to treat abnormal heart rhythms, or arrhythmias. The type of arrhythmia and the presence of other heart disease will determine whether ablation can be performed surgically or non-surgically.
Non-surgical ablation, used for many types of arrhythmias, is performed in a special lab called the electrophysiology (EP) laboratory. During this non-surgical procedure a catheter is inserted into a specific area of the heart. A special machine directs energy through the catheter to small areas of the heart muscle that causes the abnormal heart rhythm. This energy "disconnects" the pathway of the abnormal rhythm. It can also be used to disconnect the electrical pathway between the upper chambers (atria) and the lower chambers (ventricles) of the heart.
Surgical ablation procedures used for treating atrial fibrillation can be "minimally invasive" or traditional "open" surgery and may be combined with other surgical therapies such as bypass surgery, valve repair, or valve replacement. Surgical ablation procedures include:
- The Maze procedure. During this traditional open-heart surgical procedure, the surgeon makes small cuts in the heart to interrupt the conduction of abnormal impulses and to direct normal sinus impulses to travel to the atrioventricular node (AV node) as they normally should. When the heart heals, scar tissue forms and the abnormal electrical impulses are blocked from traveling through the heart.
- Minimally invasive surgical ablation. Unlike traditional heart surgery, there is no large chest wall incision and the heart is not stopped. These techniques utilize smaller incisions and endoscopes (small, lighted instruments that contain a camera).
- The modified Maze procedure. The surgeon uses a special catheter to deliver energy that creates controlled lesions on the heart and ultimately scar tissue. This scar tissue blocks the abnormal electrical impulses from being conducted through the heart and promotes the normal conduction of impulses through the proper pathway. One of four energy sources may be used to create the scars: radiofrequency, microwave, laser, or cryothermy (cold temperatures). The modified Maze procedure involves a single incision in the left atrium.
Why do I need ablation therapy?
Doctors recommend ablation therapy to treat:
- Atrial fibrillation and atrial flutter
- AV Nodal re-entry tachycardia (AVNRT)
- Accessory pathways
- Ventricular tachycardia
In addition to re-establishing a normal heart rhythm in people with certain arrhythmias, ablation therapy can help control the heart rate in people with rapid arrhythmias, and reduce the risk of blood clots and strokes.
How should I prepare for catheter ablation?
The ablation preparation may vary, depending on whether you're having surgical or nonsurgical ablation. These are general guidelines; your doctor or nurse will give you specific instructions.
To prepare for ablation, there are several steps you should take. Among them:
- Ask your doctor which medications you should stop taking and when to stop them. Your doctor may ask you to stop certain drugs (such as those that control your heart rate or blood thinners including aspirin products) one to five days before your procedure. If you are diabetic, ask your doctor how you should adjust your diabetic medications.
- Do not eat or drink anything after midnight the evening before the procedure. If you must take medications, drink only with a small sip of water.
- When you come to the hospital, wear comfortable clothes. You will change into a hospital gown for the procedure. Leave all jewelry and valuables at home.
What can I expect during catheter ablation?
During nonsurgical catheter ablation, the following things will occur:
- The procedure will take place in a special room called the EP (electrophysiology) lab. Before the test begins, a nurse will help you get ready. You will lie on a bed and the nurse will start an IV (intravenous) line in your hand or arm. This is so the doctors and nurses can give you medications and fluids through your vein during the procedure. You will be given a medication through your IV to help you relax. Depending on the type of ablation you have, you may or may not be awake during your procedure. If you are awake, you will be asked to report any symptoms, answer questions, or follow instructions given to you by your doctor. If you are uncomfortable or need anything, please let your nurse know.
- The nurse will connect you to several monitors.
- After you become drowsy, your groin area will be shaved and your neck, upper chest, arm, and groin will be cleansed with an antiseptic solution. Sterile drapes will be placed to cover you from your neck to your feet.
- The doctor will numb the insertion site by injecting a medication. You will feel an initial burning sensation, and then it will become numb. Then, several catheters (special wires that can pace the heart and record its electrical activity) will be inserted through a small incision into a large blood vessel(s) and/or artery (in your groin, neck, or arm) and advanced to your heart. If you are awake, it is important that you remain still and resist the temptation to raise your head to see what the doctor is doing while the catheters are being placed.
- After the catheters are in place, the doctor will look at the monitor to assess your heart's conduction system.
- Then, the doctor will perform the ablation procedure.
- During traditional ablation, the doctor will use a pacemaker-like device to send electrical impulses to the heart to increase your heart rate. You may feel your heart beating faster or stronger when the pacemaker delivers the impulses. If your arrhythmia occurs during the procedure, the nurse will ask you how you are feeling. It is very important to tell the doctor or nurse the symptoms you feel. The doctor will then move the catheters around your heart to see which area(s) your arrhythmia is coming from. Once the doctor finds the area of your arrhythmia, energy is applied. You may feel some discomfort or a burning sensation in your chest, but you must stay quiet, keep very still, and avoid taking deep breaths. If you are feeling pain, ask your doctor or nurse to give you more medication.
- During pulmonary vein ablation (for atrial fibrillation), the doctor delivers energy through a catheter to the area of the atria that connects to the pulmonary vein (ostia), producing a circular scar. The scar will then block any impulses firing from within the pulmonary veins, thus preventing atrial fibrillation from occurring. The process is repeated to all four pulmonary veins. In some cases, ablation may also be performed to other parts of the heart such as the subclavian veins and coronary sinus. The catheter is a special "cool tip" catheter. Fluid circulates through the catheter to help control the intensity of the temperature.
- Once the ablation is complete, the electrophysiologist will use monitoring devices to observe the electrical signals in the heart to ensure that the abnormal heart rhythm was corrected.
The procedure usually takes about four to eight hours, but may take longer.
What happens after catheter ablation?
After your nonsurgical catheter ablation:
- The doctor will remove the catheters from your groin and apply pressure to the site to prevent bleeding. You will be on bed rest for one to six hours. Keep your legs as still as possible during this time to prevent bleeding.
- After your procedure, you may be admitted to the hospital. During your recovery, a special monitor, called telemetry, will be used to follow your heart rate and rhythm. Telemetry consists of a small box connected by wires to your chest with sticky electrode patches. The box allows your heart rhythm to be displayed on several monitors on the nursing unit. The nurses will be able to observe your heart rate and rhythm. In most cases, you will be able to go home the next day after the catheter ablation procedure but in some cases you may be able to go home the same day of the procedure.
- You and your family will receive the results of the procedure afterwards. Your doctor will also discuss when you can resume activities and how often you will need to visit your doctor.
- Temporarily, many individuals experience heart palpitations on and off for a few weeks after the procedure. Sometimes you may also feel as if your abnormal heart rhythm is returning, but then it stops. These sensations are normal and you should not be alarmed. When these symptoms occur during your recovery, it is important to document them by calling your doctor or nurse as directed. Also call your doctor or nurse if you feel as if your abnormal heart rhythm has recurred.
- You may be required to take medications for a certain period of time after your procedure.
If you have any other questions, please ask your doctor or nurse. Ask your health care provider how often you will need to go for follow-up appointments.
How should I care for the wound site?
You will have a small dressing on your wound. It may be removed the next day. Keep the area clean and dry.
Call your doctor if you notice any redness, swelling, or drainage at the incision site.
What can I expect during surgical ablation?
During surgical ablation, you can expect the following:
- General anesthesia (the patient is asleep) or local anesthesia with sedation (the patient is awake but relaxed and pain-free) may be used, depending on the individual case.
- During minimally invasive surgery, the surgeon views the outer surface of the heart using an endoscope. Specialized instruments are used to locate the areas needing ablation and to create the lines of conduction block. Unlike traditional heart surgery, there is no large chest wall incision, and the heart is not stopped.
- The Maze procedure requires an incision along the sternum (breast bone). The incision may be traditional (about 6 to 8 inches long), or in some cases, minimally invasive (about 3 to 5 inches long). The heart is stopped during this procedure. A heart-lung machine oxygenates the blood and circulates it throughout the body during surgery.
- The modified Maze procedure involves using one of four different energy sources to create the lines of conduction block (radiofrequency, microwave, laser, or cryothermy). The energy probe of choice is inserted, and under direct vision, used to create the lesion lines. As in the classic Maze procedure, these lesions create lines of conduction block that interrupt the abnormal impulses and restore the normal sinus rhythm. This procedure is used primarily in patients who have atrial fibrillation and other indications for surgery.