The normal heartbeat depends upon the electrical current that flows through the heart’s electrical wiring and makes the heart muscle contract. The current normally starts within the Sinus Node which is the heart’s natural pacemaker and flows in one direction from the top chambers (atria) to the bottom chambers (ventricles). Short circuits may develop anywhere along the. electrical wiring giving rise to abnormal heart rhythms. This may result in palpitations, breathlessness, chest pains, dizziness or blackouts.
Catheter ablation is a procedure in which the short circuits are destroyed. It is usually performed by a specialist cardiologist called a Cardiac Electrophysiologist. The procedure is perfomed under local anaesthetic with light or heavy sedation. For the most complex procedures, general anaesthesia is sometimes administered. Patients are able to go home either on the day of the procedure or the following day.
During the procedure, specially designed wires called catheters (figure 1) are passed into the heart from the leg veins under X-ray guidance (figure 2). The short circuits are pinpointed by performing an Electrophysiology Study during which the abnormal heart rhythm is triggered off by delivering electrical impulses to the heart through the catheters. Once localised, the short circuits are destroyed either by heating (radiofrequency ablation) or freezing (cryoablation) the critical bits of heart muscle.
In complex ablation procedures for abnormal rhythms like Atrial Fibrillation (AF), the catheters are guided using a 3 dimensional mapping computer that minimises the need for X-rays.(Figure 3) Movie showing an image of the left atrium in a patient undergoing catheter ablation for Atrial Fibrillation (AF). Each brown dot represents an ablation site. In this patient, the AF stopped during ablation and the heart went back into a normal rhythm. The patient remains in a normal rhythm 1 year after the procedure and is not taking any rhythm control drugs.
The overall success rates of catheter ablation are excellent and range from 80% to 95% depending upon the abnormal heart rhythm. The risk of serious complications such as stroke or damage to the heart is usually 1% or less. Catheter ablation is a permanent solution for abnormal heart rhythms and is more effective than drug therapy. catheter-ablation | pacemaker | implantable-cardioverter-defibrillator