The study is a prospective, randomized, controlled trial to assess the effects of silymarin on the occurrence of postoperative atrial fibrillation after coronary artery bypass graft surgery.

Postoperative atrial fibrillation (POAF) is a frequent complication after coronary artery bypass graft (CABG) surgery and is associated with increased mortality. So far, the effects of various drugs and supplements on the occurrence of postoperative atrial fibrillation (POAF) have been studied, but no one has looked into the effect of silymarin on the occurrence of POAF.

The study is designed as a prospective, randomized, controlled trial to assess the effects of silymarin on the occurrence of postoperative atrial fibrillation after CABG surgery. A total of 160 patients of both sexes scheduled for elective CABG surgery using cardiopulmonary bypass (CPB) will be included. They will be randomized into two groups (experimental and control) with 80 patients each. Subjects in the experimental group will receive 400 mg of silymarin three days preoperatively, while subjects in the control group will receive standard therapy.

The occurrence of POAF after CABG surgery will be the primary outcome, which will be defined as any dysrhythmia that represents the ECG characteristics of atrial fibrillation lasting at least 30 s on a rhythm strip or 12-lead ECG. Secondary outcomes will include postoperative values of inflammation markers, length of stay in the ICU, length of hospitalization, and occurrence of postoperative complications (pericardial effusion, stroke, in-hospital death).

Inclusion Criteria:

• scheduled for elective CABG surgery using cardiopulmonary bypass
• first cardiac surgery
• left ventricular ejection fraction > 35%
• less than moderate mitral regurgitation

Exclusion Criteria:

• preoperative atrial fibrillation
• previous history of interventionally treated arrhythmias
• end-stage renal disease requiring hemodialysis
• chronic inflammatory and neoplastic diseases