Background

An atrial fibrillation (AF) ablation is an invasive procedure that is intended to treat AF. AF is the most common cardiac arrhythmia and is caused by disorganized and rapid electrical impulses in the atria of the heart. In an untreated patient, the ventricular rate also tends to be rapid and variable, between 120 and 160 beats/minute, but in some patients it may exceed 200 beats/minute. This is visualized on the 12-lead electrocardiogram (EKG) as a lack of discernable normal P waves, many small atrial waves preceding the QRS complex, and an irregularly irregular ventricular heart rate that varies due to the chaotic impulses from the atria. See Chapter 26: Electrocardiography for more details about EKG.

The word “ablation” comes from the Latin word ablatio , which means to take away. Ablation can be used in the medical lexicon for a procedure that causes the destruction of tissue via various techniques. In the case of AF ablation, the tissue that is targeted is located in the left atrium of the heart. This tissue predisposes patients to the arrhythmia.

How to Use It

An AF ablation may be considered for patients with AF in the following clinical scenarios ^, :

• 1.
  

  Symptomatic paroxysmal or persistent AF that is either refractory to treatment with an antiarrhythmic medication or the patient is intolerant of the medication due to side effects.

  
  
• 2.
  

  Recurrent episodes of symptomatic paroxysmal AF or symptomatic persistent AF before trying antiarrhythmic medication.

  
  
• 3.
  

  Symptomatic AF and heart failure with reduced ejection fraction.

An AF ablation should not be performed in any patient who cannot be treated with anticoagulation during and after the procedure. ^,

How It Is Done

An AF ablation is performed by an electrophysiologist who is a cardiologist with additional training in electrophysiology. Electrophysiology is the field of cardiology that specializes in electrical disorders of the heart, including arrhythmias. The procedure is performed in the electrophysiology laboratory in an inpatient setting. The electrophysiology laboratory is similar to an operating room or cardiac catheterization laboratory and contains specialized cardiac monitoring and treatment equipment.

During the procedure, the patient is required to be motionless while lying on the table for several hours. The ablation can be painful. Therefore, conscious sedation or general anesthesia is utilized for the procedure. Patients are typically informed not to eat or drink anything starting at midnight the day of the procedure.

Physically, the procedure entails :

• 1.
  

  Right heart cardiac catheterization, which involves the introduction of catheters into the right atrium of the heart via the large veins (usually femoral vein) and passing the catheter across the interatrial septum (transatrial septal puncture) into the left atrium.

  
  
• 2.
  

  Ablation of the regions of the left atrium that are known to initiate AF, which most commonly includes the regions of the left atrium around the pulmonary veins.

An extensive area of the left atrium is usually ablated. Over time, new areas can develop that trigger AF. This can be due to de novo trigger sites in the atria or areas that were not treated during the ablation procedure.

The expected outcome is that normal sinus rhythm is restored after one ablation procedure in approximately 60% of patients. For patients who undergo multiple ablation procedures, approximately 70% remain in normal sinus rhythm. Recurrence of AF in the first 3 months after the procedure is common and does not mean the procedure was not successful. Recurrence of AF after 3 months may require antiarrhythmic medication or consideration for a repeat ablation procedure.

There is a 4.5% incidence of a major complication from the procedure which includes :

• 1.
  

  Cardiac tamponade: 1.3% incidence.

  
  
• 2.
  

  Stroke or transient ischemic attack: 0.94% incidence.

  
  
• 3.
  

  Atrial-esophageal fistula: 0.04% incidence.

  
  
• 4.
  

  Death: 0.15% incidence.

Medication Implications