For patients with atrial fibrillation and heart failure, current treatment can include AV nodal ablation with biventricular pacing. Pulmonary vein isolation (PVI) is a new procedure for this patient population which attempts to restore sinus rhythm. This trial is a randomized controlled trial of AVN ablation with biventricular pacing versus PVI for atrial fibrillation patients with congestive heart failure.

Inclusion Criteria:

• Patients with symptomatic atrial fibrillation with NYHA II-III symptoms despite the use of anti-arrhythmic medications.
• Ejection fraction was required to be ≤ 40%.
• Patients were required to be on a heart failure regimen that included beta-blockers and ace-inhibitors or angiotensin receptor blockers for all patients and spironolactone for NYHA III patients.
• Patients were required to complete a 6-minute walk test and to be ≥ 18 years of age.

Exclusion Criteria:

• Reversible causes of AF and heart failure (HF) such as pericarditis, hyperthyroidism, valvular heart disease and tachycardia-induced cardiomyopathy.
• Post-operative AF, previous MAZE or MAZE-like surgery, previous left atrial instrumentation
• Life expectancy ≤ 2 years
• Likely cardiac transplant within the next 12 months
• Contraindication to anti-arrhythmic medications and/or anticoagulation
• Severe pulmonary disease
• Documented intra-atrial thrombus
• Tumor or other abnormalities which preclude catheter introduction
• Cardiac surgery, MI or PCI within the past three months.