Tehran University of Medical Sciences The Research in Heart Yield and Translational Medicine (RHYTHM) 3115-7270 21 2 2026 04 26 141 145 Kiran Kishor Pisekar U. N. Mehta Institute of Cardiology and Research Center Ritesh Shah U. N. Mehta Institute of Cardiology and Research Center Kaushal Patel U. N. Mehta Institute of Cardiology and Research Center Ramesh Patel U. N. Mehta Institute of Cardiology and Research Center Bhawana Sharma U. N. Mehta Institute of Cardiology and Research Center Cheshta Sangwan U. N. Mehta Institute of Cardiology and Research Center Pratik Shah U. N. Mehta Institute of Cardiology and Research Center 2026 02 25 2026 04 19 Atrial fibrillation (AF) is highly prevalent in patients undergoing cardiac surgery, and persistent AF poses significant challenges in postoperative rhythm management. This study investigated whether maintaining high-normal potassium levels (>4.4 mmol/L) during and after cardiopulmonary bypass (CPB) enhances SR restoration and stability in patients with persistent AF. A prospective observational study of 245 patients undergoing elective cardiac surgery was conducted, with potassium levels maintained above 4.5 mmol/L during CPB and supplemented postoperatively for 48 hours. Outcomes included SR conversion rates, hemodynamic parameters, and predictors of rhythm stability. Results showed that 87% of patients reverted to SR post-CPB, with 71% maintaining SR at 48 hours. Higher intraoperative potassium levels (mean, 4.54 vs 4.41 mmol/L; P=.02) significantly predicted successful cardioversion, whereas larger left atrial diameter (67.2 vs 53.8 mm; P<.001) correlated with AF persistence. Hemodynamic stability improved in patients with SR, with lower heart rates, higher mean arterial pressures, and reduced ICU stays (52.5 vs 58.8 h; P<.001). The study concludes that maintaining high-normal potassium levels during and after CPB facilitates SR restoration and short-term stability in patients with persistent AF, improving hemodynamics and reducing ICU dependency. Left atrial enlargement remains a key determinant of AF recurrence. These findings support perioperative potassium optimization as a feasible strategy to enhance postoperative outcomes, warranting further multicenter trials for validation. https://jthc.tums.ac.ir/index.php/jthc/article/view/2443 https://jthc.tums.ac.ir/index.php/jthc/article/download/2443/1259