The patients of the control group will undergo standard ablation procedure (pulmonary vein isolation) and will receive placebo, starting one week before scheduled ablation.

Optimal antihypertensive treatment will be prescribed, with adequate follow-up to ensure good control of hypertension (goal <= 140/90).

Patients of the active treatment group will receive moxonidine in a starting dose of 0.2 mg daily. The first dose will be administered 1 week before scheduled ablation. 3 weeks after the first dose the daily dose will be increased to 0.4 mg, if the lower dose is well tolerated.

Optimal antihypertensive treatment, in addition to moxonidine, will be prescribed, if needed, with adequate follow-up to ensure good control of hypertension (goal <= 140/90).

Any of the following, occuring after a 3-month blanking period, will be considered an AF recurrence:

• symptomatic recurrence (AF/MRAT of any duration in ECGs performed in patients reporting symptoms of arrhythmia); the patients will be encouraged to visit the research site or any affiliated center to have an ECG performed at any time (24/7) they may feel symptoms of arrhythmia during the study follow-up
• AF/MRAT of at least 30 seconds in duration in 48-hour Holter recordings performed monthly
• AF/MRAT of any duration recorded in electrocardiograms performed during patient visits at the arrhythmia clinic, even if the patient is asymptomatic

(AF=atrial fibrillation, MRAT=macro-reentrant atrial tachycardia)

The 17-item Hamilton Depression Rating Scale will be administered at baseline, and at the 3- and 6-month visits.

Any of the following, occuring within 2 months post-ablation, will be considered an early AF recurrence:

• symptomatic recurrence (AF/MRAT of any duration in ECGs performed in patients reporting symptoms of arrhythmia); the patients will be encouraged to visit the research site or any affiliated center to have an ECG performed at any time (24/7) they may feel symptoms of arrhythmia during the study follow-up
• AF/MRAT of at least 30 seconds in duration in 48-hour Holter recordings performed monthly
• AF/MRAT of any duration recorded in electrocardiograms performed during patient visits at the arrhythmia clinic, even if the patient is asymptomatic

Moxonidine-related adverse effects will be monitored and recorded, focusing on xerostomia, headaches, sleep disorders, hypotension, orthostatic hypotension