Radiofrequency Ablation of Drivers of Atrial Fibrillation
Radiofrequency Ablation of Drivers of Atrial Fibrillation
The purpose of this study is to assess the value of ablation of high frequency sources
 following circumferential pulmonary veins isolation in patients with paroxysmal and
 persistent atrial fibrillation.
Atrial fibrillation (AF) is the most common arrhythmia in clinical practice, accounts for
 one-third of arrhythmia hospitalizations and is associated with an increased risk of stroke,
 heart failure, and all-cause mortality. Moreover, there is an increasing AF prevalence due to
 aging of the population, a rising prevalence of chronic heart disease, and increased
 survival. Unfortunately, medications aimed at suppressing AF and maintaining sinus rhythm or
 at controlling ventricular rate are only marginally effective and may cause serious adverse
 effects. The limitations of pharmacologic treatment patterns have fuelled the development of
 new interventional strategies. Current techniques of AF ablation can achieve a 60-80%
 improvement in highly selected patients with medically refractory AF. However, the procedure
 is not without risk, is long-lasting and recurrence rates are still high. Moreover, the
 results in persistent AF patients are far from optimal, require the creation of extensive
 atrial lesions and repeated procedures. The main reason that explains the current situation
 is the incomplete understanding of mechanisms underlying AF maintenance despite many years of
 research and speculation. The incremental value of ablation of high frequency sources
 following circumferential PV isolation has not been assessed. There is no prospective data
 available as to the safety and benefit of such a combined approach in patients with
 paroxysmal and persistent AF. Such information would be very important in helping guide the
 future direction of ablative therapy for AF as well as helping to answer important questions
 about the role of high frequency sites in persistent AF treatment.
Inclusion Criteria:

 -  Patients age 18 or older.

 -  Patients with paroxysmal AF symptomatic and refractory to at least one antiarrhythmic
 medication.

 -  In patients with paroxysmal AF, at least one episode of AF must have been documented
 by ECG or Holter within 12 months of randomization in the trial.

 -  Patients with persistent AF defined as a sustained episode that had been present for
 more than seven days without intervening spontaneous episodes of sinus rhythm and that
 recurred within seven days after cardioversion.

 -  Patients with persistent AF must be on continuous anticoagulation with warfarin (INR
 2-3) for> 4 weeks prior to ablation. In patients with paroxysmal AF no continuous
 anticoagulation therapy with warfarin for > 4 weeks prior to ablation will be needed
 provided a transesophageal echocardiogram performed prior to ablation exclude the
 presence of thrombi or other abnormalities that discourage performing the procedure.

 -  Patients must be able and willing to provide written informed consent to participate
 in the clinical trial.

 Exclusion Criteria:

 -  Patients with AF secondary to reversible causes.

 -  Patients with inadequate anticoagulation levels as defined in the inclusion criteria.

 -  Patients with left atrial thrombus, tumor, or another abnormality which precludes
 catheter introduction on TEE prior to the procedure.

 -  Patients with contraindications to systemic anticoagulation with heparin or coumadin.

 -  Patients who have previously undergone atrial fibrillation ablation, either by surgery
 or by percutaneous catheter.

 -  Patients with left atrial size > 55 mm.

 -  Patients who are or may potentially be pregnant.

 -  Patients with hyperthyroidism or hypothyroidism.

 -  Current enrollment in another investigational drug or device study.

 -  Pacemaker or Implantable Cardioverter Defibrillator.