AV node ablation is a technique used to treat heart problems such as atrial fibrillation and atrial flutter, where the heart beats abnormally. During the procedure, a thin tube known as a catheter is inserted into a vein in the groin and guided through the circulatory system until it reaches the heart. Once inside the heart, radio waves are used to create heat energy which is directed from the catheter to destroy an area of tissue known as the AV node. The AV node carries electrical impulses from the upper heart chambers, or atria, to the lower chambers, which are known as ventricles, and its destruction means that abnormal beats occurring in the atria no longer affect the whole heart. A regular rhythm can then be restored to the ventricles by implanting an artificial pacemaker.
Normally, the heart muscle contracts because a wave of electrical impulses spreads from the atria to the ventricles. The impulses begin in the SA node, an area of specialized biological tissue in the right atrium, which acts as a natural pacemaker to generate a regular heartbeat. Sometimes, other, abnormal cells begin to generate impulses which override the ones coming from the SA node, and this can cause conditions such as atrial fibrillation, where the atria beat irregularly and too fast.
After the atria have contracted, the electrical impulses pass through the AV node and cause contraction of the ventricles. Although the impulses in atrial fibrillation happen so quickly that not all of them can pass through to the ventricles, the ventricles still end up beating faster than they normally would. The condition carries a risk of stroke or heart failure, and, if other treatments fail, AV node ablation may be carried out.
An AV node ablation usually require a hospital stay of around two nights. The procedure can be carried out using a local anesthetic, so patients remain awake. After numbing the groin, catheters are inserted into one of the veins and guided up into the heart so that wires can be threaded along them. These wires are used to detect the correct area for tissue removal, and their positions are monitored using an X-ray machine. Once the precise spot for surgical removal has been determined, a different catheter is inserted which can deliver the radio wave energy necessary to destroy the AV node tissue.
Following AV node ablation, an artificial pacemaker is fitted. The pacemaker wire is guided into the heart through a catheter inserted into a vein in the chest. Once the wire is in place, the pacemaker box, which generates electrical signals, is positioned under the skin of the chest.
Complications are rare after AV node ablation, but occasionally the vein in the groin could be damaged. The heartbeat may be monitored for a couple of days following the procedure. In the long term, patients will need to take medication to prevent blood clotting and will always require a pacemaker.