The aim of this clinical study is to evaluate the efficacy and tolerability of probiotics on atrial fibrillation recurrence.

Assessment of AF recurrence: Early AF recurrence is defined as relapse into AF within 1 week following successful cardioversion and AF recurrence through the study's 12-week follow-up.

Patients and Methods Design: Prospective, randomized, open label, controlled clinical trial

Patients: A total of 56 AF patients undergoing cardioversion will be randomly enrolled into one of 2 arms:

1. Group 1 (Control group) (n=28): AF patients undergoing cardioversion who will receive the standard of care
2. Group 2 (Probiotic group) (n = 28): AF patients undergoing cardioversion who will receive the standard of care in addition to probiotics DAILY orally administered (Probiotics 25 billion) after cardioversion for 12 weeks.

Groups (1 & 2) will be subjected to cardioversion on admission according to standard protocols and criteria.

Inclusion Criteria:

1. Female or male aged 40 years or above with BMI less than 40
2. Persistent AF patients directly after cardioversion

Exclusion Criteria:

1. History of probiotic supplementation in the previous 6 weeks
2. Autoimmune diseases
3. Ongoing treatment with immunosuppressive therapies
4. Active Infection
5. Pregnant or breast-feeding patients
6. Active participation in another clinical study
7. History of or known allergy or intolerability to the study medications