CARDIAC ABLATION.

Cardiac ablation is a procedure that can correct heart rhythm problems (arrhythmias).

Cardiac ablation works by scarring or destroying tissue in your heart that triggers an abnormal heart rhythm. In some cases, ablation prevents abnormal electrical signals from traveling through your heart and thus stops the arrhythmia.

Ablation typically uses catheters — long, flexible tubes inserted through a vein in your groin and threaded to your heart — to correct structural problems in your heart that cause an arrhythmia.

Cardiac ablation is sometimes done through open-heart surgery, but it's often done using catheters, making the procedure less invasive and shortening recovery times.

Symptoms

Common symptoms of heart rhythm problems may include:

• Chest pain
• Fainting
• Fast or slow heartbeat (palpitations)
• Light-headedness, dizziness
• Paleness
• Shortness of breath
• Skipping beats - changes in the pattern of the pulse
• Sweating

Rhythms treated with Cardiac Ablation

Normally, the heart’s impulses travel down an electrical pathway through the heart. The atria and ventricles work together, alternately contracting and relaxing to pump blood through the heart. The electrical system of the heart is the power source that makes this possible. Each electrical impulse causes the heart to beat. Catheter ablation can be used to treat:

• AV Nodal Re entrant Tachycardia (AVNRT): An extra pathway lies in or near the AV node, which causes the impulses to move in a circle and re-enter areas it already passed through.
• Accessory Pathway: Extra pathways can exist from birth that connect the atrium and ventricles. The extra pathway causes signals to travel back to the atrium, making it beat faster.
• Atrial Fibrillation and Atrial Flutter: Extra signals originating in different parts of the atrium cause the atria to beat rapidly (atrial flutter) or quiver (atrial fibrillation).
• Ventricular Tachycardia: A rapid, potentially life-threatening rhythm originating from impulses in the ventricles. The rapid rate prevents the heart from filling with enough blood, and less blood is able to circulate through the body.

Types of Cardiac Ablation

Surgical Ablation

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.

Catheter Ablation

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.

Contra-indications

• Left atrial ablation and ablation for persistent atrial flutter should not be performed in the presence of known atrial thrombus.
• Mobile left ventricular thrombus is a contra-indication to left ventricular ablation.
• Mechanical prosthetic heart valves are generally not crossed with ablation catheters.
• Women should not be exposed to fluoroscopy if there is any possibility that they are pregnant.

Risks

Catheter ablation is thought to be safe. It has some serious risks, but they are rare. They include:

• Stroke.
• Heart attack.
• Puncture of the heart.
• Need for emergency heart surgery.
• Problems with the pulmonary vein.
• A leaking blood vessel.
• Nerve damage that causes paralysis of the diaphragm.
• Pericarditi.
• Cardiac tamponade.
• Atrio-esophageal fistula. In this life-threatening condition, a hole forms between the heart's upper chamber and the esophagus.
• Bleeding.
• New heart rhythm problems.
• Death (very rare).

You will have to decide whether the possible benefits of ablation outweigh these risks. Your doctor can help you decide.

Outlook

Catheter ablation alone doesn't always restore a normal heart rate and rhythm. You may need other treatments as well. Also, some people who have the procedure may need to have it done again. This can happen if the first procedure doesn't fully correct the problem.