A normal heartbeat is controlled by a regular and constant flow of electricity all through the heart. A short circuit at any location along this electrical pathway can disrupt the normal flow of signals, causing an arrhythmia (ie. an irregular heartbeat). Cardiac ablation is a minimally invasive procedure that is used to destroy these short-circuits and to restore normal rhythm, or is used to block damaged electrical pathways from sending faulty signals to the rest of the heart.
What is an Ablation?
An ablation is performed by an electrophysiologist (EP), a physician specializing in treating and diagnosing heart rhythm disorders. During a catheter ablation, catheters (narrow flexible tubes) are inserted into a blood vessel, often through a small puncture site in the upper thigh or neck, and guided through the vein under X-ray guidance until they reach the heart. Small Platinum electrodes on the tip of the catheters record and stimulate the activity of the heart. This test, called an electrophysiology study (EPS), allows the EP to pinpoint the exact location of the short circuit. When the location is confirmed, the short circuit is either blocked to reopen the normal electrical pathway or blocked to prevent it from sending faulty signals to the rest of the heart. This is achieved by sending energy through a catheter tip to destroy a small amount of tissue at the site. The energy may be either hot (ie. radiofrequency energy), which cauterizes the tissue, or very cold, which freezes or cryoablates it.
Is a Cardiac Ablation Right for You?
Ablation is used to treat many different types of arrhythmias. It is successful in 90% to 98% of cases, often eliminating the need for long-term drug therapy or open-heart surgery. Cardiac ablation might be an option for the following cases:
· If you can’t tolerate or do not wish to take medication to treat your arrhythmia.
· If you have ventricular tachycardia (VT), an ablation is sometimes used in combination with an ICD.
· If your arrhythmia can’t be controlled with medication or lifestyle changes.
· If you have a supraventricular tachycardia.
There are a many types of ablations available to patients with abnormal heart rhythms.
Atrial fibrillation ablation
Pulmonary vein isolation – Most atrial fibrillation (AFib) signals originate in the pulmonary veins. Ablations are performed to create many lesions (scars) to form a circular scar around the four pulmonary veins during this procedure. The scar thereby blocks any impulses firing from within the pulmonary veins to reach the rest of the heart, thereby “isolating” or "disconnecting" the pathway of the abnormal rhythm.
Ablation of the AV node – An ablation is performed to damage the AV node (the electrical bridge between the atria and ventricles). This results in a very slow heart rate, since the electrical signals from the atria can’t travel down to the ventricles. To maintain an adequate heart rate, a permanent pacemaker is then required.
Atrial flutter ablation
In Atrial Flutter, the electrical signal travels along a pathway solely within the right atrium. It moves in a circular organized motion, or "circuit," causing the atria to beat a lot faster than the ventricles. The fast, but regular pattern of AFL is what makes it different from AFib. AFL makes a very distinct "sawtooth" pattern on a test used to diagnose abnormal heart rhythms, the electrocardiogram (ECG). Atrial flutter ablation is performed by applying energy to a spot in the right atrium named the isthmus to stop electrical signals from traveling through this spot.
Types of ablations
There are numerous ablation techniques related to the type of energy used, type of catheter used, and the types of lesions created.
Radiofrequency ablation – A special catheter that delivers radiofrequency energy is used to heat the heart tissue and produce a lesion.
Cryoablation – Extremely cold temperatures are emitted through a probe (called a cryoprobe) in order to create lesions.
Surgical ablation – Surgical procedures can also be used for treating AFib. These procedures can either be traditional open surgery or minimally invasive, and can be combined with other surgical procedures such as valve repair or replacement or cardiac bypass surgery.