Electrical cardioversion– the rhythm reset
Electrical cardioversion is a procedure in which a patient receives an electrical shock on the outside of the chest (while under mild anesthesia) using either paddles or patches. The shock can be used to “reset” the heart to a normal rhythm. The procedure is similar to defibrillation, but uses much lower levels of electricity.
The decision to use electrical cardioversion
Your provider may recommend a transesophageal echocardiography (TEE) as a first step. The TEE procedure involves swallowing a small ultrasound device that allows the healthcare team to look inside your heart atria for blood clots.
If you already have clots in the atria, you will need protection from increasing your stroke risk. For this reason, your healthcare provider may recommend that you take a blood thinner before having an electrical cardioversion procedure. It often successfully restores regular heart rhythm, but for some patients their atrial fibrillation may return. In many instances, anti-arrhythmia medications are needed indefinitely to keep the heart’s rhythm and rate in the best range.
Radiofrequency ablation or catheter ablation
Ablation is used for cardiac arrhythmias when long-term medications or electrical cardioversion are either not preferred or were not effective. Before ablation surgery, electrical mapping of the heart is performed. An electrically sensitive catheter is used to map the heart muscle and the origins of the “extra” electrical activity throughout the heart. The map tells the physician which areas of the heart are creating problematic electric signals that interfere with the proper rhythm.
How is an ablation performed?
A catheter (thin, flexible tube) is inserted into the patient’s blood vessels and is gently guided to the heart. The physician carefully destroys malfunctioning tissue using the catheter to deliver energy (such as radiofrequency, laser or cryotherapy) to scar the problematic areas. The scarred areas will no longer send abnormal signals. If successful, the heart will return to a normal rhythm. This minimally invasive procedure usually has a short recovery period. Patients are generally placed on a short course of anti-arrhythmic drugs while the procedure takes full effect.
Common types of ablation for AF include:
- Pulmonary vein isolation ablation (PVI ablation or PVA). In some AF patients, fibrillation is triggered by extra electrical currents in the pulmonary veins. During this procedure, the catheter tip is used to destroy the tissue that is sending the extra currents and, in most cases, normal heart rhythm returns.
- AV node ablation with pacemakers. In other AF patients, the trigger for their AF occurs in the AV node (the place where the electrical signals pass from the atria to the ventricles). The catheter is placed near the AV node and a small area of tissue is destroyed. A pacemaker is then implanted to restore and maintain the heart’s normal rhythm.