Applied Evidence

When is catheter ablation a sound option for your patient with A-fib?

Author and Disclosure Information

 

References

Successful ablation is defined as freedom from symptomatic or asymptomatic AF episodes, and depends on AF type; duration and degree of symptoms; and age, sex, and comorbidities.

Electrical current is applied through the catheters from an external generator to stimulate the myocardium and thus determine its electrophysiologic properties. The anatomic and electrical activity of the left atrium and pulmonary veins is then identified, a technique known as electro-anatomical mapping (FIGURE). After arrhythmogenic myocardial tissue is mapped, ablation is carried out with RF energy through the catheter to the pathogenic myocardium from which arrhythmias are initiated or conducted. The result is thermal destruction of tissue and creation of small, shallow lesions that vary in size with the type of catheter and the force of contact pressure applied.3,29

Creating a left atrial electro-anatomical map

Other energy sources used in catheter ablation include cryothermal energy, which utilizes liquid nitrous oxide under pressure through a cryocatheter or cryoballoon catheter. Application of cryothermal energy freezes tissue and disrupts cell membranes and any electrical activity. Cryoballoon ablation has been shown to be similarly safe and efficacious as RF ablation in patients with paroxysmal AF.30,31

Newer laser-based balloon ablations are performed under ultrasonographic guidance and utilize arcs of laser energy delivered to the pathogenic myocardium.3

Thromboembolism prophylaxis

Oral anticoagulation to decrease the risk of stroke is initiated in all patients with AF, based on a thromboembolic risk profile determined by their CHA2DS2–VASc score, with anticoagulation recommended when the score is ≥ 2 in men and ≥ 3 in women. Options for anticoagulation include warfarin and one of the novel oral anticoagulants dabigatran, apixaban, rivaroxaban, and edoxaban.4 Recommendations are as follows3:

  • For patients with a CHA2DS2–VASc score of ≥ 2 (men) or ≥ 3 (women), anticoagulation should be continued indefinitely, regardless of how successful the ablation procedure is.
  • When patients choose to discontinue anticoagulation, they should be counseled in detail about the risk of doing so. The continued need for frequent arrhythmia monitoring should be emphasized.

The route from primary careto catheter ablation

Perform a thorough evaluation. Patients who present to you with palpitations should first undergo a routine workup for AF, followed by confirmation of the diagnosis. Exclude structural heart disease with echocardiography. Undertake monitoring, which is essential to determine whether symptoms are a reflection of the arrhythmia, using noncontinuous or continuous electrocardiographic (EKG) monitoring. Noncontinuous detection devices include:

  • scheduled or symptom-initiated EKG
  • a Holter monitor, worn for at least 24 hours and as long as 7 days
  • trans-telephonic recordings and patient- or automatically activated devices
  • an external loop recorder.32

Continuous EKG monitoring is more permanent (≥ 12 months). This is usually achieved through an implantable loop powered by a battery that lasts as long as 3 years.3

Ablation: Yes or no? Ablation is not recommended to avoid anticoagulation or when anticoagulation is contraindicated.5 With regard to specific patient criteria, the ideal patient:

  • is symptomatic
  • has failed AAD therapy
  • does not have pulmonary disease
  • has a normal or mildly dilated left atrium or normal or mildly reduced left ventricular ejection fraction.5

Continue to: There is no absolute age...

Pages

Next Article: