STOP AF First: Cryoballoon Catheter Ablation in an Antiarrhythmic Drug Naive Paroxysmal Atrial Fibrillation

Subjects with paroxysmal atrial fibrillation with no history of treatment with
anti-arrhythmic drugs are randomized 1:1 to either an anti-arrhythmic drug or pulmonary vein
isolation using the cryoballon catheter.

Inclusion Criteria:

- A diagnosis of symptomatic paroxysmal AF with the following documentation: (1)
physician's note indicating recurrent self- terminating AF or paroxysmal AF; and (2)
any ECG documented AF within 6 months prior to enrollment.

- Age 18-80

Exclusion Criteria:

- History of AF treatment with class I or III antiarrhythmic drug, including sotalol,
with the intention to prevent an AF recurrence. However, patients pretreated with
above AAD for less than 7 days with the intention to convert an AF episode are
allowed.

- Prior persistent AF (cardioversion after 48 hours or continuous AF that is sustained
>7 days)

- Left atrial diameter greater than 5.0 cm

- Prior left atrial ablation or left atrial surgical procedure

- Presence or likely implant of a permanent pacemaker, biventricular pacemaker, loop
recorder, or any type of implantable cardiac defibrillator (with or without
biventricular pacing function)

- Body mass index (BMI) >35 kg/m2

- Presence of any pulmonary vein stents

- Known presence of any pre-existing pulmonary vein stenosis

- Pre-existing hemidiaphragmatic paralysis

- Presence of any cardiac valve prosthesis

- Moderate or severe mitral valve regurgitation or stenosis

- Any cardiac surgery, myocardial infarction, percutaneous coronary intervention/
percutaneous transluminal coronary angioplasty or coronary artery stenting which
occurred during the 90 day interval preceding the date the subject signed the Informed
Consent Form

- Unstable angina

- New York Heart Association (NYHA) class III or IV congestive heart failure and/or
known left ventricular ejection fraction (LVEF) less than 45%

- Diagnosis of primary pulmonary hypertension

- Rheumatic heart disease

- Thrombocytosis, thrombocytopenia

- Contraindication to anticoagulation therapy

- Active systemic infection

- Hypertrophic cardiomyopathy

- Cryoglobulinemia

- Known reversible causes of AF, including but not limited to uncontrolled
hyperthyroidism, obstructive sleep apnea, and acute alcohol toxicity.

- Any cerebral ischemic event (strokes or transient ischemic attacks) which occurred
during the 180 day interval preceding the date the subject signed the Informed Consent
Form, or any known unresolved complications from previous stroke/transient ischemic
attack

- Existing thrombus

- Pregnancy

- Patient with life expectancy that makes it unlikely 12 months of follow-up will be
completed.

- Current or anticipated participation in any other clinical trial of a drug, device or
biologic during the duration of this study not pre-approved by Medtronic

- Patients with contraindications to a Holter monitor

- Unwilling or unable to comply fully with study procedures and follow-up