Atrial Fibrillation Ablation: Indications and Complications

Your heart is made of four chambers, the left and right atrium, and the left and right ventricle. The healthy heart beats regularly to pump blood to the body. Each heart beat is triggered by an electrical signal from a group of special cells in the wall of the right atrium, which are together called, the sinoatrial node (SA node). The electrical signal then travels through the wall of the atria and reaches another group of special tissue called the atrio-ventricular node (AV node); from here the electrical impulse is transmitted to the wall of the ventricles to signal contraction.

What is Atrial Fibrillation Ablation?

Atrial fibrillation is a disorder in which the atria contract inefficiently and chaotically (arrhythmia), due to faulty electrical signals. The tissue which generates the faulty electrical signal is called a hot spot. Ablating these hot spots helps in normalising the rhythm and rate of contraction and providing relief from the symptoms and long term consequences of atrial fibrillation. The procedure for ablating these hot spots is called Atrial fibrillation ablation. Ablation can be done by numerous methods:

• Catheter ablation: your surgeon gains access to the heart with the help small tube called a catheter. With the help of the catheter the surgeon applies either extreme heat or cold to destroy the hot spot or its connection to the normal electrical pathway. This creates a scar which efficiently disrupts the faulty signal cycle and restores the atria to normal rhythm.
• Maze procedure: the surgeon gains access to the heart via an open heart surgery and creates a maze of scar tissue in the atria with the help of an ablation device or a scalpel. This effectively disrupts the stray electrical signals.
• AV node ablation: when other methods for controlling atrial fibrillation do not work, your surgeon might suggest you undergo an AV node ablation. During this procedure your doctor will ablate the electrical tissue which acts as a connection between the atria and the ventricle effectively cutting off the electrical signals from the ventricles. You will need a pacemaker device to control the beating of your ventricles after this procedure.

Once diagnosed it is imperative to treat atrial fibrillation either medically or surgically, because this condition deteriorates over time.

Procedure

• Catheter ablation: for this procedure your doctor will give you sedatives to help you stay relaxed. After the sedatives take effect your surgeon will numb a small area in your groin or shoulder and insert a needle into the vein. A sheath is introduced subsequently. A thin tube called a catheter is introduced into this sheath and moved forward to reach the heart. The tip of the catheter contains an electrode that can transmit and receive electrical signals. Your surgeon might use the catheter to inject a dye into the heart to visualise it better with the help of x ray. After the catheter reaches the heart the tip of the electrode is used to find the hot spots in the wall of the atria. On finding the target tissue the surgeon uses either extreme heat (radiofrequency) or cold (cryoablation) to create a scar tissue.
• AV node ablation: the doctor will ablate the AV node which is present at the junction of the atria and the ventricles. After this a pacemaker will be attached to your heart to help the ventricles pump blood.
• Maze: your surgeon will create a pattern of scars on your heart with the help of a scalpel or an ablation device which will disrupt the stray electrical signals. This is done during open heart surgery for valves or blockage in heart arteries. The surgery is done under general anaesthesia. You will be placed on a cardio pulmonary bypass while your surgeon works on your heart.

Indications for Atrial Fibrillation Ablation

Atrial fibrillation ablation is suggested for patients whose symptoms cannot be controlled by medications. The symptoms of atrial fibrillation are:

• Pain in the chest
• Palpitations: acute awareness of one’s heartbeat
• Shortness of breath
• Weakness
• Dizziness
• Excessive sweating

It is imperative to treat atrial fibrillation once it has been diagnosed because it only worsens over time. Atrial fibrillation increases your risk of stroke.

Preparation

To prepare for the surgery your Cardiologist will order a series of tests, to evaluate the health of your heart, after taking a thorough history and physical examination. Your doctor would like to know about the medications you’ve been taking and may make some changes to them in preparation for the surgery. Inform your doctor about any allergies to medications that you might have. Your doctor would like to know if you have an Implantable Cardioverter Defibrillator(ICD) or a pacemaker. You will be asked to stop eating and drinking the night before the surgery.

Complications of Atrial Fibrillation Ablation

The complications encountered depend upon the procedure used to treat atrial fibrillation. They are:

• Infection at the site where catheter was introduced
• Stroke
• Clot formation in the veins of the legs or lungs
• Damage to blood vessels
• Narrowing of the vein carrying blood to the heart from the lung (pulmonary vein stenosis)
• Damage to heart valves
• Damage to the electrical system of the heart that may worsen the arrhythmia
• Rupture of a wall of the heart

Recovery

Following a catheter ablation you will be monitored as the effect of the sedatives wane. Depending on your vitals you will be allowed to go home on the same day or the next day. It is advisable to arrange for someone to drive you home. You might feel a bit sore for a few days after the surgery. Your doctor will schedule an appointment with you for a follow up.

Resources:

• http://www.heart.org/HEARTORG/Conditions/Arrhythmia/PreventionTreatmentofArrhythmia/Ablation-for-Arrhythmias_UCM_301991_Article.jsp#.WzmvH9IzY2x
• http://www.onlinejacc.org/content/59/2/150?_ga=2.252141386.2114102610.1530465836-1046297554.1526022527