Atrial Fibrillation Ablation
Atrial fibrillation is a type of arrhythmia, or abnormal heart rhythm. In atrial fibrillation, the electrical signals from the upper chambers of the heart (the atria) are fast and irregular. This causes the atria to quiver instead of beating effectively.
Atrial Fibrillation Ablation
The newest ablation procedures for atrial fibrillation involve using catheters to isolate or eliminate the triggers that start atrial fibrillation. These triggers are commonly coming from the pulmonary veins, which return blood from the lungs into the left atrium. Access to the left atrium is required for the procedure, which involves making a small hole in the septum from the right into the left atrium (transseptal catheterization or puncture).
The doctor inserts the catheters into the heart through the large veins in the groin. Most of the time, the doctor places the catheter near the edges of the pulmonary veins and delivers energy to disconnect the triggers from the rest of the left atrium. Ablation uses a small amount of energy to deliver a small "burn" to the heart cells to electrically disconnect them.
Atrial fibrillation ablation is most successful in patients with frequent paroxysmal episodes, with a normal heart. The success decreases in patients who are in atrial fibrillation all the time, or have a very large, stretched-out left atrium. Some patients still have episodes of atrial fibrillation after the ablation procedure. These episodes are often less frequent and easier to control with medications. There is a 10–20 percent chance of recurrence after a successful procedure due to reconnection of the triggers, requiring a second procedure. In general, a single procedure will result in 70–75 percent chance of cure or significant improvement in atrial fibrillation symptoms.
The Ablation Procedure
Typically, you will come to the hospital on the day of the procedure. We will ask you to stop Warfarin/Coumadin several days before the procedure and to use low molecular weight heparin injections to maintain your blood thin until that day. Our electrophysiology team will meet you that day to answer any additional questions you have. An anesthesiologist will also meet you. We frequently use general anesthesia to keep you comfortable through the procedure. A number of ECG recordings pads will be placed in your body. These pads monitor your heart rhythm, and can also be used for electrical cardioversion. You may undergo one or more electrical cardioversions to put you in regular rhythm during the procedure.
After you are sedated, we will introduce several catheters through your veins (groin/neck) to your heart. A transesophageal echocardiogram is performed to rule out the presence of an atrial clot in the left atrium. It also helps the doctor to perform the transseptal catheterization (crossing from the right to the left atrium) with the catheters. We do this by puncturing through a small membrane located between both atria. As soon as we enter the left atrium, your blood is thinned with heparin to avoid forming blood clots. The blood will remain thin through the procedure. Then, we will create a map of your left atrium and pulmonary veins using the catheters, a sophisticated mapping system and the previously obtained CT angiogram of your chest. After this, we will start giving the ablation lesions to isolate the triggers of your atrial fibrillation.
Risks of the Atrial Fibrillation Ablation Procedure
Catheter ablation is a low-risk procedure. However, some of the complications can be potentially serious. You need to ask all your questions before the procedure, and understand the risks and weigh them against the risks and benefits of other therapies to treat atrial fibrillation.
- There is a small risk of bleeding and damaging the blood vessels where the catheters are inserted. If it happens, it can be repaired surgically if necessary.
- There is a risk of heart puncture and bleeding through the heart walls during the transseptal catheterization. It a significant amount of blood surrounds the heart sac or pericardial space, it will need to be removed with a needle and a catheter. In occasions, surgery may be required.
- The manipulation and presence of catheters in the left atrium can cause a stroke. We minimize this risk with the use of heparin after the transseptal puncture. This risk may be increased if you have a history of previous stroke or TIA. Catheter manipulation and the ablation lesions can also cause perforation of the heart walls.
- There is the risk of damaging or narrowing the pulmonary veins with the ablation lesions. If a significant narrowing occurs it may require another procedure to stretch the narrowed area or to place a stent to keep the veins open.
- A communication between the left atrium and the esophagus (your swallowing tube) can be caused by the burn of the ablation. This is called an atrioesophageal fistula. This is a rare complication, but very serious and potentially lethal. We monitor the temperature inside the esophagus during the procedure to minimize this risk.
In addition to these complications, unforeseen allergic reactions to medications may occur. There is also a small risk of infection, valve damage, or heart attack related to the procedure. Finally, there is always the very small chance that one of these or other unexpected complication can cause death. Despite our vigilance, the risk of complications from the procedure is 3 to 5 percent.