GSTM1 and atrial fibrillation: A fib: atrial fibrillation; BMI: body mass index; Cr: creatinine; Hb: hemoglobin; HF: heart failure; LVIDd: left ventricular internal diameter diastolic; LVIDs: left ventricular internal diameter systolic; MI: myocardial infarction; NYHA: New York Heart Association; O2: oxygen; PPM: permanent pacemaker; STS Score: Society of Thoracic Surgeons Score