Ablation Therapy for Cardiac Arrhythmias

cardiac catheterization
Dan Porges/Getty Images

If you have a cardiac arrhythmia that is seriously disrupting your life or is posing a risk to your health, your doctor may have brought up the possibility of treating it with an ablation procedure.

Some arrhythmias are caused by localized abnormalities within the heart’s electrical system. In these cases, an ablation procedure may be able to disrupt the electrical abnormality. The goal of an ablation procedure usually is to get rid of the arrhythmia altogether.

How Is An Ablation Procedure Performed?

While ablation procedures can be performed in the operating room during open-heart surgery, by far the most common form of ablation is accomplished during a specialized form of cardiac catheterization, called an electrophysiology study (EP study)

EP studies are performed by cardiac electrophysiologists - cardiologists with special training in the treatment of cardiac arrhythmias. An EP study may be done as a diagnostic procedure when it is important to tease out very precisely the mechanism of a person’s cardiac arrhythmia - often, to decide whether an ablation procedure would be likely to cure the arrhythmia. Today, many EP studies combine the diagnostic test with an ablation procedure.

During an ablation procedure, specialized catheters with electrodes at the tip are positioned at various locations inside the heart, and the entire cardiac electrical system is studied and mapped.

If an abnormal area is identified that is responsible for producing the arrhythmia, the tip of the catheter is guided to that abnormal area, and an ablation is performed through the catheter. The ablation is accomplished by transmitting some form of energy through the catheter (heat energy, freezing energy, or microwave energy), in order to damage the tissue at the tip of the catheter.

In recent years, ablation procedures have become quite advanced, and typically employ sophisticated computerized mapping systems that utilize both 3-D imaging and electrical mapping to pinpoint the appropriate site for ablation.

What Kinds of Arrhythmias Can Be Ablated

In some cases an arrhythmia can be caused by a focus of cardiac cells that, for one reason or another, begins to fire off extra electrical impulses, creating premature atrial complexes (PACs) or premature ventricular complexes (PVCs). Depending on where these foci of cells are located, ablation may be possible. However, since PACs and PVCs are usually non-life-threatening, most people who have these arrhythmias do not need ablation procedures. Ablation of PACs and PVCs is usually done only when these arrhythmias are creating intolerable symptoms, or in cases where they are triggering reentrant tachycardias.

Reentrant tachycardias are generally caused by abnormal electrical connections within the heart. If the abnormal connection can be precisely mapped, it can often be ablated successfully.

Reentrant arrhythmias that are generally ablated with a great deal of success include AV nodal reentrant tachycardiaatrioventricular reentrant tachycardia(including Wolff-Parkinson-White syndrome), and atrial flutter

Ablation procedures aimed at eliminating atrial fibrillation have been evolving for several years, but successfully and reliably ablating this arrhythmia has proven to be difficult. This is because the electrical disruptions associated with atrial fibrillation are usually not localized, but encompass the entirety of both the right and left atrium. Several approaches have been used over the years, some yielding more success than others. But overall, the results of atrial fibrillation ablation procedures have been mixed.

However, a different kind of ablation procedure has been effective in controlling most of the symptoms of atrial fibrillation in selected patients, without getting rid of the arrhythmia itself. Read about this alternative ablation procedure for atrial fibrillation here. 

What Are the Complications?

While ablation procedures are usually relatively safe, complications can occur. The risk of complications depends to a large extent on the type of arrhythmia being ablated - the risk of treating atrial fibrillation with ablation is substantially higher than it is for most other kinds of arrhythmias.

Anyone considering an ablation procedure must weight the potential benefits of getting rid of a life-disrupting arrhythmia, that might otherwise require the use of potentially toxic anti-arrhythmic drugs, against the risk of the ablation procedure.

Complications of ablation may include creating heart block (requiring a pacemaker), bleeding, blood clots which may produce stroke and trauma to the heart due to the ablation itself. Because risks vary so much depending on the specific arrhythmia being treated, it is very important that people thinking about this procedure have a detailed discussion of the potential pros and cons with their electrophysiologist. 

Sources:

Ganesan AN, Shipp NJ, Brooks AG, et al. Long-term outcomes of catheter ablation of atrial fibrillation: a systematic review and meta-analysis. J Am Heart Assoc 2013; 2:e004549.

Bohnen M, Stevenson WG, Tedrow UB, et al. Incidence and predictors of major complications from contemporary catheter ablation to treat cardiac arrhythmias. Heart Rhythm 2011; 8:1661.

Tracy CM, Akhtar M, DiMarco JP, et al. American College of Cardiology/American Heart Association 2006 update of the clinical competence statement on invasive electrophysiologystudies,catheterablation,andcardioversion: a report of the American College of Cardiology/American Heart Association/American College of Physicians Task Force on Clinical Competence and Training developed in collaboration with the Heart Rhythm Society. J Am Coll Cardiol 2006; 48:1503.

Continue Reading