• Acute treatment with elimination of AF episodes [ Time Frame: 12 months ] [ Designated as safety issue: No ]
• Death, stroke, and hospitalization for recurrence of AF [ Time Frame: within 12 months of treatment ] [ Designated as safety issue: Yes ]

• Elimination of AF episodes at 12 months
• Safety profile of treatment

The purpose of this study is to determine if the HIFU Pulmonary Vein Ablation System is effective in the treatment of paroxysmal Atrial Fibrillation compared to the control of best medical therapy with FDA approved antiarrhythmic drugs.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia affecting an estimated 2.2 million persons in the United States (US). In addition to being debilitating, AF has been identified as a leading risk factor for stroke. AF is often associated with structural heart disease, but a substantial number of AF patients have little or no detectable structural heart disease. A patient with AF is up to 5 times more likely to have a stroke than the general population.

Recently, it has been demonstrated that for a significant portion of AF patients (80% - 95 %) the arrhythmia originates in one of the four pulmonary veins (PV's). Furthermore, it has been shown that isolation of this arrhythmia by ablation can, in the majority of patients (50-70%), eliminate or markedly reduce episodes of AF. Currently, there are a number of modalities being investigated to treat AF. They include radiofrequency, laser, thermal, cryo, microwave, and ultrasound ablation of targeted areas in the atrium and/or PVs.

Comparison(s): Clinical success of High Intensity Focused Ultrasound (HIFU) Ablation for Pulmonary Vein Isolation in the treatment of Atrial Fibrillation, compared to medical therapy with anti-arrhythmic drugs (AADs).

• Drug: propafenone
• Drug: flecainide
• Drug: dofetilide
• Drug: sotolol
• Device: Pulmonary vein ablation
• Drug: Amiodarone

• Active Comparator: Class I or III anti-arrhythmic drug for the treatment of AF
• Experimental: Pulmonary vein ablation with HIFU

Inclusion Criteria:

• Documented atrial fibrillation
• Failed or intolerant to at least 1 anti-arrhythmic drug
• Able to take anti-coagulant therapy
• Able to complete screening tests required for inclusion/exclusion criteria
• Able to take at least 1 approved anti-arrhythmic drug
• Not pregnant
• Available for follow-up for at least 12 months

Exclusion Criteria:

• Persistent or permanent atrial fibrillation
• Mitral disease
• Prior surgical treatment for atrial fibrillation
• Ablation for treatment of atrial fibrillation within 6 months
• Severe left ventricular hypertrophy
• Known untreated coagulopathy
• Unstable angina
• Prior stroke
• Uncontrolled heart failure
• Secondary causes of atrial fibrillation
• Uncorrected hyperthyroidism within 12 months
• Pulmonary embolism within 6 months
• Pneumonia or acute pulmonary disease within 3 months
• Pacemaker/ICD
• High risk for esophageal disease
• Currently enrolled in investigational drug or device study