High level of calcium in the atrial myocytes plays a role in the formation and progression of the AF owing to abbreviating action potential time and atrial refractory period.32 Also calcium provides to development of atrial enlargement and electrophysiological remodeling.33 Contrary to this, there were no difference statistically between the POAF group and non POAF group in terms of calcium and PTH in our study and the both parameters were normal range. Here, PTH is linked to atrial fibrillation.