A double-blind randomized clinical trial comparing different doses of magnesium in cardioplegic solution for prevention of atrial fibrillation after coronary artery bypass graft surgery

Association between preprocedural serum potassium level and atrial fibrillation recurrence after catheter ablation

BACKGROUND

The association between serum potassium and atrial fibrillation (AF) recurrence after catheter ablation remains unclear.

OBJECTIVE

To investigate whether preprocedural serum potassium influences AF recurrence in patients underwent catheter ablation.

METHODS

We used data of AF patients who underwent de novo catheter ablation from the prospective Chinese Atrial Fibrillation Registry Study (CAFR). Patients with prior ablation and without baseline serum potassium were excluded. The primary outcome was 1-year AF recurrence after 3-month blanking period from the ablation. Restricted cubic spline and Cox proportional models were used to compare outcomes across serum potassium categories.

RESULTS

A total of 4838 AF patients with de novo catheter ablation was enrolled. At 1 year, AF recurrence occurred in 1347 (27.8%) patients. The relationship between preprocedural serum potassium and 1-year AF recurrence after ablation presented as U-shape (P for nonlinear = 0.048). Compared with the group of serum potassium within 4.41-4.60 mmol/L, the risk of AF recurrence increased significantly in the lowest serum potassium group (≤4.00 mmol/L) after multivariate analysis (HR 1.26, 95% CI 1.06-1.51, P = 0.010). Other categories with lower or higher serum potassium levels including 4.01-4.20 mmol/L (HR=1.18), 4.21-4.40 mmol/L (HR=1.16), 4.61-4.80 mmol/L (HR=1.07) and ≥4.81 mmol/L (HR=1.11) showed nonsignificant higher recurrence risk.

CONCLUSIONS

The relationship between preprocedural potassium and AF recurrence was U-shaped, with an optimal potassium range (4.41-4.60 mmol/L). Lower potassium level is associated with increased AF recurrence risk after catheter ablation.

Alteration of plasma trace elements magnesium, copper, zinc, iron and calcium during and after coronary artery bypass grafting surgery

BACKGROUND

Dietary factors including trace elements contribute to the development of disorders including coronary artery diseases. Whether there are differences in concentrations of trace elements between on-pump and off-pump coronary artery bypass grafting (CABG) surgery remains unclear. The aim of this study was to investigate the differences in the plasma level of four trace elements Cu, Fe, Zn, magnesium (Mg), and calcium (Ca) during and after CABG between on-pump and off-pump procedure and the correlation between these trace elements and the development of postoperative AF.

METHODS

Fifty-three CABG patients using on-pump or off-pump methods were enrolled. The blood sample was taken before skin incision (T1), 4 h after skin incision (T2), postoperative day1 (T3), and day3 (T4) respectively. Plasma concentrations of Mg, Ca, Fe, Zn, and Cu were determined.

RESULTS

The plasma Mg concentration reached the highest level at T3 (0.94 ± 0.03 vs. 1.20 ± 0.03 mmol/L,P < 0.001) and completely recovered at T4 whereas Zn (11.28 ± 0.23 vs. 6.80 ± 0.20 mmol/L, P < 0.001) and Fe (10.97 ± 0.51 vs. 2.22 ± 0.1 μmol/L, P < 0.001) was lowest at T3 and partially recovered at T4. Cu was lowest at T2 (12.10 ± 0.33 vs. 9.62 ± 0.25 μmol/L, P < 0.001) then increased until T4. There were significant differences in Mg and Fe (P < 0.05), as well as Cu (P < 0.01) between on-pump and off-pump groups. No significant differences were detected between postoperative atrial fibrillation and sinus rhythm groups.

CONCLUSIONS

In CABG, Cu and Zn are significantly reduced and Cu is recovered at postoperative Day 1 but Zn takes longer to recover. Addition of Mg and Ca during CABG are sufficient to maintain the plasma concentration. However, supplementation of Cu and Zn during and after CABG may be necessary. Further, the correlation between these trace elements and postoperative AF is to be further determined.

Postoperative complications associated with coronary artery bypass graft surgery and their therapeutic interventions

Coronary artery disease is one of the commonest surgery demanding cardiovascular diseases. Coronary artery bypass graft surgery is practiced all over the world for the treatment of coronary artery disease. Systemic trauma during the surgery is associated with a wide range of complications, some of which are fatal. Preoperative risk factors such as age, previous illness and obesity are common predictors of these adverse events. Advances in therapeutic medicine have allowed timely treatment of these adverse events and co-morbidities. This review summarizes some of the most occurring complications associated with coronary artery bypass graft and corresponding treatment options.

Postoperative Atrial Fibrillation Following Cardiac Surgery: From Pathogenesis to Potential Therapies

Postoperative atrial fibrillation (POAF) is a major complication after cardiac surgery which can lead to high rates of morbidity and mortality, an enhanced length of hospital stay, and an increased cost of care. POAF is postulated to be a multifactorial phenomenon; however, some major pathogeneses have been proposed, including inflammatory pathways, oxidative stress, and autonomic dysfunction. Genetic studies also showed that inflammatory pathways, beta-1 adrenoreceptor variants, G protein-coupled receptor kinase 5 gene variants, and non-coding single-nucleotide polymorphisms in the 4q25 chromosomal locus are involved in this phenomenon. Moreover, several predisposing factors lead to the development of POAF, consisting of pre-, intra-, and postoperative contributors. The main predisposing factors comprise age, prior history of major cardiovascular risk factors, and ischemia-reperfusion injury during surgery. The management of POAF is based on the usual therapies used for non-surgical AF, including medications for either rate control or rhythm control in hemodynamically unstable patients. The perioperative administration of β-blockers and some antiarrhythmic agents has been recommended in major international guidelines. In addition, upstream therapies consisting of colchicine, magnesium, statins, and antioxidants have attenuated the incidence of POAF; however, some uncomfortable side effects developed in large randomized trials. The use of anticoagulation has also resulted in less mortality in patients with POAF at higher risk of thromboembolic events. Despite these recommendations, the actual regimen for the prevention of POAF remains controversial. In this review, we highlight the pathogenesis, predisposing factors, and potential therapeutic options for the management of patients at risk for or with POAF following cardiac surgery.