A catheter ablation procedure, otherwise known as radiofrequency ablation or cryotherapy ablation, is a procedure usually performed after an electrophysiology (EP) study has identified a cardiac arrhythmia that is responsive to curative ablation.
An electrophysiology study is a procedure utilized to study the electrical system of a patient’s heart. An arrhythmia, or heart rhythm disturbance, is any electrical disturbance that can occur in the heart, starting from either the upper atria or lower ventricles. This arrhythmia can be a bradyarrhythmia (slow heart rhythm) or tachyarrhythmia (fast heart rhythm). Your electrophysiologist will evaluate your symptoms and endeavor to catch this arrhythmia with an EKG monitoring method, such as a Holter or Event monitor. If you have continued symptoms even with medications, or an unclear diagnosis after an extensive workup for arrhythmia, your electrophysiologist may decide to order an electrophysiology study and possible catheter ablation.
When is an Ablation the best option?
Patients with symptomatic arrhythmias and/or clearly verified arrhythmias are usually referred to an electrophysiologist for an EP study and possible catheter ablation. Patients may include those with the following:
- Symptomatic arrhythmias even with medications.
- Unbearable side effects from the prescribed medications for their arrhythmia and decide they prefer a curative catheter ablation.
- Prefer a curative catheter ablation first-line to avoid medications.
- Hazardous Occupations including pilots, police, fireman, etc..
Catheter ablation for supraventricular tachycardias (SVT), or those that begin in the upper chambers of the heart, are typically very successful with cure rates > 95%. These types of SVT include:
- Atrial flutter
- Atrial tachycardia (AT)
- AV nodal reentrant tachycardia (AVNRT)
- AV reciprocating tachycardia (AVRT)
Catheter ablation for atrial fibrillation is complex since atrial fibrillation has may different influencers that may result in the arrhythmia. Typically, ablation success can vary from 70-80% if the patient is otherwise healthy. Ablation continues to remain the most effective tool for managing atrial fibrillation.
Catheter ablation for ventricular tachycardia (VT) is more complex. Those patients with “focal” ventricular tachycardia with no indication of structural heart disease can be ablated with a high rate of success if they fail medical therapy first. Patients with structural heart disease and “reentrant” ventricular tachycardia are a more difficult subgroup of patients. These patients usually have an ICD implanted and are referred to an electrophysiologist after failed antiarrhythmic therapy due to recurrent ICD shocks. Catheter ablation of VT can be performed in these patients with success rates greater than 50-70%. A thoughtful discussion with your electrophysiologist to develop a customized treatment plan is crucial.
How the Ablation Procedure is Performed
You will be transported to a special EP laboratory room and prepped with continuous monitoring devices that measure your blood pressure, EKG, pulse, and oxygen saturation throughout the ablation procedure. As an extra safety precaution, a pair of large defibrillation pads will be attached to your chest and back and connected to an external cardiac defibrillator. Rarely is the defibrillator used during a procedure.
After you have arrived in the EP Lab, the nurses will dispense an intravenous sedation to help you to relax during the procedure. You may be awake during the procedure but relaxed though may patients are placed under deep sedation. After giving you a local anesthetic medication to numb the area of entry, your electrophysiologist will place several catheters, normally thru the veins in the groin or neck, into the heart under fluoroscopic (X-ray), guidance. These catheters are placed in precise areas critical to the heart’s normal conduction system, such as the right atrium, right ventricle and the His bundle.
These intracardiac catheters allow your electrophysiologist to measure the electrical activity in your heart and will also allow him to perform pacing maneuvers in various cardiac chambers in an effort to initiate your cardiac arrhythmia in a controlled fashion. If successful in starting the arrhythmia, your electrophysiologist will be able to electrically map the origin and mechanism of the arrhythmia.
If your arrhythmia is responsive to catheter ablation, your electrophysiologist will use specialized catheters that can deliver radiofrequency (heat) or cryotherapy (cold) energy from an externally connected generator to the local cardiac muscle tissue that is causing your heart rhythm disturbance often resulting in cure from the arrhythmia.
Catheter ablation of the cardiac muscle tissue leads to localized injury. The heart function is usually not affected by the small and focally-directed ablation lesions.
Catheter ablation with cryoablation (freezing) is a widely accepted and clinically useful technology in the EP lab today.
Electrophysiologists perform cryoablation to restore normal heart rhythm by disabling heart cells that create an irregular heartbeat.
Studies have found cryoablation to be significantly more effective than medication, and patients normally experience less pain than with radiofrequency ablation.
What Happens During Cryoablation for Atrial Fibrillation
During this minimally invasive procedure, the electrophysiologist inserts a balloon catheter into a blood vessel, usually in the upper leg, and then gently moves it through the patient’s body until it reaches the heart. Utilizing advanced imaging techniques, the electrophysiologist guides the catheter to the heart. The specialized catheter has an inflatable balloon on one end that engages the pulmonary vein. After the balloon is at the ostium of the pulmonary vein, extremely cold energy flows through the catheter to destroy a tiny amount of tissue that is triggering an irregular heartbeat and thus maintains a healthy heart rhythm.
Understanding the Difference Between Heat-Based Ablation and Cryoablation
Heat-based ablation using radiofrequency (RF) catheters has some risk of complications, for example, esophageal injury. Cryoablation helps electrophysiologists prevent these risks by utilizing cold instead of heat to deactivate abnormal heart tissue. Cryoablation permits electrophysiologists to cool the tissue to confirm it is the area of the heart that is causing the irregularity. If it is not the correct location, then the normal electrical function can be easily re-established by letting the tissue to thaw and re-warm.
Your electrophysiologist will discuss all of these issues with you during your pre-procedure office visit.
What to Expect Post-procedure
Your post-procedure recovery is expected to be uneventful. The catheters are removed after the procedure, usually in the EP lab. You will be moved to the hospital recovery area where you will be monitored until you are fully. Typically you will be instructed to keep your leg straight for at least 4 hours after the catheters have been removed to reduce the chance of developing any bleeding at the incision site. If the ablation procedure is successful and no issues have occurred, you may be observed overnight and discharged the next morning.
The risk potential for a catheter ablation procedure is small, but, as with any invasive procedure, it’s not risk-free. Your electrophysiologist will discuss with you the following possible procedure-related complications:
- bleeding at the entry site
- injury to the artery or veins at the location of the catheter placement
- damage to the heart or vascular structures that require surgery or implantation of a pacemaker
- lung damage
- blood clots in the veins
- stroke, MI, or death
These risks are 1% or less. Your electrophysiologist will review these risks with you in-depth on the day of your procedure.
Discharge instructions and care
Your electrophysiologist will discuss specific recommendations regarding your discharge care. The following are general recommendations:
- Avoid heavy lifting or strenuous exertion for 4-5 days after your procedure.
- You may shower after your return home.
- You may remove any bandages placed at the incision site once you return home.
- You may return to work in 1-2 days.
Call your electrophysiologist if your incision site appears to swell or becomes more painful.
Developing some bruising at the catheter site is normal. However, it should not become more painful or lead to increased swelling.
Make a follow-up appointment with your electrophysiologist in approximately one month.