The purpose of this study is to collect preliminary safety and effectiveness data evaluating the Toray Satake Balloon Thermal Ablation System (TSB)to treat subjects with symptomatic paroxysmal atrial fibrillation that is resistant to antiarrhythmic drug therapy.

Inclusion Criteria:

• Diagnosis of recurrent symptomatic paroxysmal atrial fibrillation
• ≥2 Symptomatic atrial fibrillation episodes
• At least 1 paroxysmal atrial fibrillation episode documented by an ECG or device recording system in the 6 months prior to enrollment AND
• At least 1 additional (for a total of ≥2) paroxysmal atrial fibrillation episode documented by an ECG or device recording system, OR, at a minimum, a physician's note indicating recurrent symptomatic atrial fibrillation
• No episode >7 days
• Failed to respond to or is intolerant of ≥1 Class I, II, III or IV antiarrhythmic drug
• Able and willing to provide informed consent and Health Insurance Privacy and Portability Act (HIPAA) authorization
• Able and willing to meet all study requirements, including attending all post-ablation procedure assessments and visits

Exclusion Criteria:

• Left atrium ≥50 mm
• Chronically used amiodarone in the 3 months prior to enrollment
• Previous left atrial ablation or surgical treatment for atrial fibrillation
• Left ventricular ejection fraction (LVEF) <35 %
• New York Heart Association (NYHA) Class III or IV heart failure
• History of myocardial infarction (MI) or unstable angina in the 6 months prior to enrollment
• Multiple other exclusion criteria to establish overall good health and likely study compliance