Objective: Our study was designed to assess the incidence of atrial fibrillation, changes of serum electrolyte concentrations following coronary artery bypass grafting surgery.
Material and methods: After approval of Kaunas Region Ethics Committee for Biomedical Research and written informed consent of the patients the data of 82 patients undergoing elective coronary artery bypass grafting surgery in Kaunas Heart Center, Clinic of Cardiac Surgery, during the period of 2004-2005 were analyzed. Serum potassium, sodium, ionized magnesium, ionized calcium, chloride and phosphate levels were measured before cardiopulmonary bypass, on arrival to intensive care unit and 18-20 hours after the surgery. Cardiac rhythm was monitored throughout the study. All patients were divided into two groups. Group I (n=22) included patients with postoperative atrial fibrillation. Group II (n=60) included patients, who remained in sinus rhythm after the surgery.
Results: The overall incidence of atrial fibrillation was 26.83%. The patients in group I were significantly older than in group II (68.27+/-6.09 and 64.20+/-9.32 years, respectively; p=0.025). Immediately after the surgery serum chloride concentration was higher in group I comparing to group II (111.91+/-4.48 and 105.17+/-5.73 mmol/l, respectively; p<0.001). Serum phosphate level was lower in group I (0.98+/-0.15 and 1.09+/-0.19 mmol/l, respectively; p=0.013). At 18-20 hours after the surgery in the group I ionized calcium was lower comparing to group II (0.97+/-0.06 and 1.00+/-0.05 mmol/l, respectively; p=0.021). Serum phosphate level was lower in group I also (0.81+/-0.16 and 0.99+/-0.20 mmol/l, respectively; p<0.001).
Conclusions: 1. The incidence of atrial fibrillation after coronary artery bypass surgery remains relatively high (26.83%). 2. Serum electrolyte concentration after coronary artery bypass grafting varies within normal ranges. 3. Patients with postoperative atrial fibrillation had higher chloride and lower phosphate concentration immediately after surgery and lower ionized calcium and phosphate level 18-20 hours after the surgery.