Patients with Hb ≤ 12 g/dL were significantly more likely to be classified in higher NYHA classes (p = 0.045), and to have a history of myocardial infarction (p = 0.036), hypertension (p = 0.045), valvular disease (p = 0.038), and bleeding events (p = 0.027). This evidence concerns the gene GSTM1 and myocardial infarction.