The association between low serum calcium level and new-onset atrial fibrillation after coronary artery bypass grafting.

OBJECTIVES: This study aims to investigate the relationship between serum calcium levels and the incidence of postoperative atrial fibrillation in patients undergoing coronary artery bypass graft surgery.

METHODS: This retrospective, observational cohort study consecutively enrolled patients undergoing isolated coronary artery bypass grafting in Beijing Anzhen hospital from January 2018 to December 2021. Patients with a previous history of atrial fibrillation or atrial flutter or requiring concomitant cardiac surgery were excluded. A logistic regression model was used to determine predictors of postoperative atrial fibrillation. Multivariable adjustment, inverse probability of treatment weighting, and propensity score matching were used to adjust for confounders. Moreover, we conducted univariable and multivariable logistic regression analyses on preoperative and postoperative serum calcium and ionized serum calcium levels.

RESULTS: The analysis encompassed 12,293 patients. The postoperative atrial fibrillation rate was significantly higher in patients with low serum calcium level than those without (1379 [33.9%] versus 2375 [28.9%], P < 0.001). Low serum calcium level was associated with an increased odds ratio of postoperative atrial fibrillation (odds ratio [95% CI]: 1.27 [1.18-1.37], P < 0.001). Inverse probability of treatment weighting and propensity score matching analyses confirmed the results. The increased postoperative atrial fibrillation rate in low serum calcium level group still existed among subgroup analysis based on different age, sex, body mass index, hypertension, hyperlipidemia, CHA2DS2-VASc and magnesium.

CONCLUSIONS: Low serum calcium level indicates elevated postoperative atrial fibrillation risk in patients undergoing isolated coronary artery bypass graft surgery even after the adjustment for age, sex, cardiovascular risk factors, echocardiographic parameters and laboratory markers.