EXercise Cardiac Magnetic Resonance Assessment of Left Atrial Mechanics Following Ablation

Who May Qualify: - Age ≥18 years - Diagnosis of paroxysmal AF - Left ventricular ejection fraction ≥50% - Scheduled for catheter ablation - Able to speak, hear, and read English - Willing and able to provide willing to sign a consent form Who Should NOT Join This Trial: - Persistent or permanent AF - Prior ablation (catheter based or surgical) for AF - Significant sinus node dysfunction - Implanted pacemaker or defibrillator - Contraindication to or inability to complete cardiovascular magnetic resonance study - Contraindication to or inability to complete exercise testing - Chronic kidney disease with estimated glomerular filtration rate \<30 mL/min/1.73m2 - Severe left ventricular hypertrophy - Unrelated cardiomyopathy that is expected to limit exercise capacity, including but not limited to: - Hypertrophic cardiomyopathy - Cardiac amyloidosis - Constrictive pericarditis - Pulmonary arterial hypertension - Prior cardiac surgery - Active pregnancy Always talk to your doctor about whether this trial is right for you.