GSTM1 and heart failure: A fib: atrial fibrillation; 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: Society of Thoracic Surgeons