Substrate Versus Trigger Ablation for Paroxysmal Atrial Fibrillation

INCLUSION CRITERIA:

   - male or female >21 years

   - reported incidence of at least two documented episodes of symptomatic paroxysmal
   atrial fibrillation (AF) during the three months preceding trial entry (at least 1
   episode documented by 12-lead ECG or ECG rhythm strip)

   - women without childbearing potential or women of childbearing potential who are not
   pregnant per a serum HCG test

   - refractory to at least one Class I or III anti-arrhythmic medications. Drug doses must
   be therapeutic and stable

   - willingness, ability and commitment to participate in baseline and follow-up
   evaluations without participation in another clinical trial (unless documented
   approval received from both sponsors)

   - oral anticoagulation required for those subjects who have a score of two or more based
   on the following criteria (CHAD score):

      - Congestive heart failure (1 point)

      - hypertention (1 point)

      - age 75 years or older (2 points)

      - diabetes (1 point)

      - prior stroke or transient ischemic attack (2 points)

      - vascular disease (1 point)

      - age 65 years or older (1 point)

      - sex category: female (1 point)

   - patient is willing and able to remain on anti-coagulation therapy for a minimum of 3
   months post procedure for all subjects, and potentially indefinitely post procedure if
   the patient has CHAD score >or=2

   - signed informed consent after a full discussion of the risks and benefits of both
   therapy arms, and the concept of randomization

   - NYHA Class 0,I, II stable on medical therapy for > 3months

   - left atrial diameter
   - LVEF >or=40%

   - sustained AF during the procedure

EXCLUSION CRITERIA:

   - atrial fibrillation from a reversible cause (e.g., surgery, hyperthyroidism,
   pericarditis)

   - cardiac or thoracic surgery within the past 180 days

   - AF secondary to electrolyte imbalance, thyroid disease

   - contraindication to Heparin

   - Contraindication to Warfarin or other novel oral anticoagulants

   - history of significant bleeding abnormalities

   - history of significant blood clotting abnormalities, systemic thrombi or systemic
   embolization

   - ASD closure device, LAA closure device, prosthetic mitral or tricuspid valve

   - atrial clot/thrombus on imaging such as on a trans-esophageal echocardiogram (TEE)
   within 72 hours of the procedure

   - intramural thrombus or other cardiac mass that may adversely effect catheter
   introduction or manipulation

   - significant pulmonary embolus within 6 months of enrollment

   - acute illness or active systemic infection or sepsis that may ordinarily warrant
   postponement of the procedure

   - history of recent cerebrovascular disease (stroke or TIA) or systemic thromboembolism
   within < 6 months

   - NYHA classes III, IV

   - heart failure that is not stable on medical therapy

   - pulmonary edema, that may make planned anesthesia or sedation difficult

   - stable/unstable angina or ongoing myocardial ischemia

   - myocardial infarction (MI) within the past three months

   - structural heart disease of clinical significance including:

      - congenital heart disease where the abnormality or its correction prohibit or
      increase the risk of ablation

      - acquired heart disease that may increase risk of ablation, such as significant
      ventricular septal defect post myocardial infarction

      - rheumatic valve disease, since this produces a unique AF phenotype

      - extreme left atrial enlargement (LA volume index > 60 ml/m2) in whom PVI has low
      success and 55 mm baskets are too small for the atria

   - cardiac transplantation or other cardiac surgery planned within the 12 month followup
   period of the trial

   - life expectancy less than 12 months (the followup period of the trial)

   - significant pulmonary disease (e.g., COPD) or any other disease that significantly
   increase the risk to the patient from sedation or anesthesia

   - untreatable allergy to contrast media

   - at time of ablation procedure, clinically significant abnormalities in serum
   potassium, sodium, magnesium or other electrolytes that affect the suitability of the
   patient for ablation at that time