Systemic Magnesium to Reduce Postoperative Arrhythmias After Coronary Artery Bypass Graft Surgery: A Meta-Analysis of Randomized Controlled Trials

The role of magnesium in cardiac arrest

Cardiac arrest is a leading cause of death globally. Only 25.8% of in-hospital and 33.5% of out-of-hospital individuals who achieve spontaneous circulation following cardiac arrest survive to leave the hospital. Respiratory failure and acute coronary syndrome are the two most common etiologies of cardiac arrest. Effort has been made to improve the outcomes of individuals resuscitated from cardiac arrest. Magnesium is an ion that is critical to the function of all cells and organs. It is often overlooked in everyday clinical practice. At present, there have only been a small number of reviews discussing the role of magnesium in cardiac arrest. In this review, for the first time, we provide a comprehensive overview of magnesium research in cardiac arrest focusing on the effects of magnesium on the occurrence and prognosis of cardiac arrest, as well as in the two main diseases causing cardiac arrest, respiratory failure and acute coronary syndrome. The current findings support the view that magnesium disorder is associated with increased risk of cardiac arrest as well as respiratory failure and acute coronary syndrome.

Magnesium prophylaxis of new-onset atrial fibrillation: A systematic review and meta-analysis

PURPOSE

Atrial fibrillation (AF) is the most common cardiac arrhythmia in intensive care units (ICU) and is associated with increased morbidity and mortality. Magnesium prophylaxis has been shown to reduce incidence of AF in cardiac surgery patients, however, evidence outside this population is limited. The objective of this study is to summarize studies examining magnesium versus placebo in the prevention of NOAF outside the setting of cardiac surgery.

SOURCE

We performed a comprehensive search of MEDLINE, EMBASE, and Cochrane Library (CENTRAL) from inception until January 3rd, 2023. We included all interventional research studies that compared magnesium to placebo and excluded case reports and post cardiac surgery patients. We conducted meta-analysis using the inverse variance method with random effects modelling.

PRINCIPAL FINDINGS

Of the 1493 studies imported for screening, 87 full texts were assessed for eligibility and six citations, representing five randomized controlled trials (n = 4713), were included in the review, with four studies (n = 4654) included in the pooled analysis. Administration of magnesium did not significantly reduce the incidence of NOAF compared to placebo (OR 0.72, [95% CI 0.48 to 1.09]).

CONCLUSION

Use of magnesium did not reduce the incidence of NOAF, however these studies represent diverse groups and are hindered by significant bias. Further studies are necessary to determine if there is benefit to magnesium prophylaxis for NOAF in non-cardiac surgery patients.

Utility of magnesium sulfate in the treatment of rapid atrial fibrillation in the emergency department: a systematic review and meta-analysis

Atrial fibrillation with rapid ventricular response (Afib/RVR) is a frequent reason for emergency department (ED) visits and can be treated with a variety of pharmacological agents. Magnesium sulfate has been used to prevent and treat postoperative Afib/RVR. We performed a systematic review and meta-analysis to assess the effectiveness of magnesium for treatment of Afib/RVR in the ED. PubMed and Scopus databases were searched up to June 2021 to identify any relevant randomized trials or observational studies. We used Cochrane's Risk-of-Bias tools to assess study qualities and random-effects meta-analysis for the difference of heart rate (HR) before and after treatment. Our search identified 395 studies; after reviewing 11 full texts, we included five randomized trials in our analysis. There were 815 patients with Afib/RVR; 487 patients (60%) received magnesium treatment, whereas 328 (40%) patients received control treatment. Magnesium treatment was associated with significant reduction in HR [standardized mean difference (SMD), 0.34; 95% CI, 0.21-0.47; P < 0.001; I2 = 4%), but not associated with higher rates of sinus conversion (OR, 1.46; 95% CI, 0.726-2.94; P = 0.29), nor higher rates of hypotension and bradycardia (OR, 2.2; 95% CI, 0.62-8.09; P = 0.22). Meta-regressions demonstrated that higher maintenance dose (corr. coeff, 0.17; P = 0.01) was positively correlated with HR reductions, respectively. We observed that magnesium infusion can be an effective rate control treatment for patients who presented to the ED with Afib/RVR. Further studies with more standardized forms of control and magnesium dosages are necessary to assess the benefit/risk ratio of magnesium treatment, besides to confirm our observations.

Preoperative Oral Magnesium loading to prevent postoperative Atrial Fibrillation following Coronary Surgery (POMAF-CS): A prospective randomized controlled trial

OBJECTIVES

Postoperative atrial fibrillation is common following coronary artery bypass grafting surgery. Hypomagnesemia is frequent after coronary artery bypass grafting surgery. No previous trials have assessed the effect of preoperative magnesium loading on postoperative atrial fibrillation incidence.

METHODS

Design: This was a single-center, double-blind, placebo-controlled, parallel-group trial, with balanced randomization [1:1]. Participants: were recruited from November 2018 until May 2019. Patients received either 3.2 g of magnesium daily (4 tablets of 0.4 g each twice daily) for 72 hours preoperatively and 1.6 g of magnesium (4 tablets) on the day of surgery, or placebo tablets.

RESULTS

The primary outcome was the incidence of postoperative atrial fibrillation. Secondary outcomes included time to extubation, transfusion rate, critical care unit and hospital length of stay. Of the 210 randomized participants, 200 (100 in each group) completed the study. 10 (10%) and 22(22%) subjects developed postoperative atrial fibrillation in the magnesium and placebo groups, respectively (RR = 0.45, 95% CI: 0.23 - 0.91). Hospital and critical care unit length of stay were comparable between the 2 groups. No side effect related to magnesium administration were documented.

CONCLUSION

In this randomized controlled trial, preoperative loading with oral administration of magnesium for 3 days in patients admitted for coronary artery bypass grafting surgery decreases the incidence of postoperative atrial fibrillation compared to placebo (NCT03703349).

CLINICAL TRIAL REGISTRY NUMBER

NCT03703349.

Role of Prophylactic Magnesium Supplementation in Prevention of Postoperative Atrial Fibrillation in Patients Undergoing Coronary Artery Bypass Grafting: a Systematic Review and Meta-Analysis of 20 Randomized Controlled Trials

Background

Several randomized trials have evaluated the efficacy of prophylactic magnesium (Mg) supplementation in prevention of post-operative atrial fibrillation (POAF) in patients undergoing cardiac artery bypass grafting (CABG). We aimed to determine the role of prophylactic Mg in 3 different settings (intraoperative, postoperative, intraoperative plus postoperative) in prevention of POAF.

Methods

A systemic literature search was performed (until January 19, 2019) using PubMed, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials to identify trials evaluating Mg supplementation post CABG. Primary outcome of our study was reduction in POAF post CABG.

Results

We included a total of 2,430 participants (1,196 in the Mg group and 1,234 in the placebo group) enrolled in 20 randomized controlled trials. Pooled analysis demonstrated no reduction in POAF between the two groups (RR 0.90; 95% CI, 0.79-1.03; p=0.13; I2=42.9%). In subgroup analysis, significant reduction in POAF was observed with postoperative Mg supplementation (RR 0.76; 95% CI, 0.58-0.99; p=0.04; I2=17.6%) but not with intraoperative or intraoperative plus postoperative Mg supplementation (RR 0.77; 95% CI, 0.49-1.22; p = 0.27; I2=49% and RR 0.92; 95% CI, 0.68-1.24; p = 0.58; I2=51.8%, respectively).

Conclusions

Magnesium supplementation, especially in the postoperative period, is an effective strategy in reducing POAF following CABG.

Epidural analgesia for adults undergoing cardiac surgery with or without cardiopulmonary bypass

BACKGROUND

General anaesthesia combined with epidural analgesia may have a beneficial effect on clinical outcomes. However, use of epidural analgesia for cardiac surgery is controversial due to a theoretical increased risk of epidural haematoma associated with systemic heparinization. This review was published in 2013, and it was updated in 2019.

OBJECTIVES

To determine the impact of perioperative epidural analgesia in adults undergoing cardiac surgery, with or without cardiopulmonary bypass, on perioperative mortality and cardiac, pulmonary, or neurological morbidity.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase in November 2018, and two trial registers up to February 2019, together with references and relevant conference abstracts.

SELECTION CRITERIA

We included all randomized controlled trials (RCTs) including adults undergoing any type of cardiac surgery under general anaesthesia and comparing epidural analgesia versus another modality of postoperative pain treatment. The primary outcome was mortality.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by Cochrane.

MAIN RESULTS

We included 69 trials with 4860 participants: 2404 given epidural analgesia and 2456 receiving comparators (systemic analgesia, peripheral nerve block, intrapleural analgesia, or wound infiltration). The mean (or median) age of participants varied between 43.5 years and 74.6 years. Surgeries performed were coronary artery bypass grafting or valvular procedures and surgeries for congenital heart disease. We judged that no trials were at low risk of bias for all domains, and that all trials were at unclear/high risk of bias for blinding of participants and personnel taking care of study participants.Epidural analgesia versus systemic analgesiaTrials show there may be no difference in mortality at 0 to 30 days (risk difference (RD) 0.00, 95% confidence interval (CI) -0.01 to 0.01; 38 trials with 3418 participants; low-quality evidence), and there may be a reduction in myocardial infarction at 0 to 30 days (RD -0.01, 95% CI -0.02 to 0.00; 26 trials with 2713 participants; low-quality evidence). Epidural analgesia may reduce the risk of 0 to 30 days respiratory depression (RD -0.03, 95% CI -0.05 to -0.01; 21 trials with 1736 participants; low-quality evidence). There is probably little or no difference in risk of pneumonia at 0 to 30 days (RD -0.03, 95% CI -0.07 to 0.01; 10 trials with 1107 participants; moderate-quality evidence), and epidural analgesia probably reduces the risk of atrial fibrillation or atrial flutter at 0 to 2 weeks (RD -0.06, 95% CI -0.10 to -0.01; 18 trials with 2431 participants; moderate-quality evidence). There may be no difference in cerebrovascular accidents at 0 to 30 days (RD -0.00, 95% CI -0.01 to 0.01; 18 trials with 2232 participants; very low-quality evidence), and none of the included trials reported any epidural haematoma events at 0 to 30 days (53 trials with 3982 participants; low-quality evidence). Epidural analgesia probably reduces the duration of tracheal intubation by the equivalent of 2.4 hours (standardized mean difference (SMD) -0.78, 95% CI -1.01 to -0.55; 40 trials with 3353 participants; moderate-quality evidence). Epidural analgesia reduces pain at rest and on movement up to 72 hours after surgery. At six to eight hours, researchers noted a reduction in pain, equivalent to a reduction of 1 point on a 0 to 10 pain scale (SMD -1.35, 95% CI -1.98 to -0.72; 10 trials with 502 participants; moderate-quality evidence). Epidural analgesia may increase risk of hypotension (RD 0.21, 95% CI 0.09 to 0.33; 17 trials with 870 participants; low-quality evidence) but may make little or no difference in the need for infusion of inotropics or vasopressors (RD 0.00, 95% CI -0.06 to 0.07; 23 trials with 1821 participants; low-quality evidence).Epidural analgesia versus other comparatorsFewer studies compared epidural analgesia versus peripheral nerve blocks (four studies), intrapleural analgesia (one study), and wound infiltration (one study). Investigators provided no data for pulmonary complications, atrial fibrillation or flutter, or for any of the comparisons. When reported, other outcomes for these comparisons (mortality, myocardial infarction, neurological complications, duration of tracheal intubation, pain, and haemodynamic support) were uncertain due to the small numbers of trials and participants.

AUTHORS' CONCLUSIONS

Compared with systemic analgesia, epidural analgesia may reduce the risk of myocardial infarction, respiratory depression, and atrial fibrillation/atrial flutter, as well as the duration of tracheal intubation and pain, in adults undergoing cardiac surgery. There may be little or no difference in mortality, pneumonia, and epidural haematoma, and effects on cerebrovascular accident are uncertain. Evidence is insufficient to show the effects of epidural analgesia compared with peripheral nerve blocks, intrapleural analgesia, or wound infiltration.

Magnesium sulphate replacement therapy in cardiac surgery patients: A systematic review

OBJECTIVE

The objective of this review was to identify evidence to inform clinical practice guidelines for magnesium sulphate (MgSO₄) replacement therapy for postoperative cardiac surgery patients.

DATA SOURCES

Three databases were systematically searched: CINAHL Complete, MEDLINE Complete, and EmBase.

REVIEW METHOD USED

A systematic literature review method was used to locate, appraise, and synthesise available evidence for each step of the medication management cycle (indication, prescription, preparation, administration, and monitoring) for MgSO₄ replacement therapy. Database searches used combinations of synonyms for postoperation or surgery, cardiac, heart, arrhythmia, atrial fibrillation, and magnesium sulphate. Search results were independently screened for inclusion by two researchers at title, abstract, and full-text stages with good statistical agreement (kappa scores of 0.99, 0.87, and 1.00, respectively).

RESULTS

Twenty-four included studies reported varying methodologies, data collected, and medication management practices. Of these, 23 studies (95.8%) excluded patients with comorbidities commonly observed in clinical practice. This review identified low-level evidence for two practice recommendations: (i) concurrent administration of MgSO₄ with medications recommended as the best practice for prevention of postoperative atrial fibrillation and (ii) clinical and laboratory monitoring of magnesium blood serum levels, vital signs, and electrocardiography should be performed during MgSO₄ replacement therapy. Evidence to inform MgSO₄ replacement therapy for each medication management cycle step was limited; therefore, a guideline could not be developed.

CONCLUSIONS

Although MgSO₄ is routinely administered to prevent hypomagnesaemia in postoperative cardiac surgery patients, there was insufficient evidence to guide critical care nurses in each medication management cycle step for MgSO₄ replacement therapy. These findings precluded the development of comprehensive recommendations to standardise this practice. Poor standardisation can increase the risk for patient harm related to variation in clinical processes and procedural errors. In light of this evidence gap, consensus of expert opinion should be used as a strategy to guide MgSO₄ medication management.

Evaluating the effect of magnesium supplementation and cardiac arrhythmias after acute coronary syndrome: a systematic review and meta-analysis

BACKGROUND

Atrial and ventricular cardiac arrhythmias are one of the most common early complications after cardiac surgery and these serve as a major cause of mortality and morbidity after cardiac revascularization. We want to evaluate the effect of magnesium sulfate administration on the incidence of cardiac arrhythmias after cardiac revascularization by doing this systematic review and meta-analysis.

METHODS

The search performed in several databases (SID, Magiran, IranDoc, IranMedex, MedLib, PubMed, EmBase, Web of Science, Scopus, the Cochrane Library and Google Scholar) for published Randomized controlled trials before December 2017 that have reported the association between Magnesium consumption and the incidence of cardiac arrhythmias. This relationship measured using odds ratios (ORs) with a confidence interval of 95% (CIs). Funnel plots and Egger test used to examine publication bias. STATA (version 11.1) used for all analyses.

RESULTS

Twenty-two studies selected as eligible for this research and included in the final analysis. The total rate of ventricular arrhythmia was lower in the group receiving magnesium sulfate than placebo (11.88% versus 24.24%). The same trend obtained for the total incidence of supraventricular arrhythmia (10.36% in the magnesium versus 23.91% in the placebo group). In general the present meta-analysis showed that magnesium could decrease ventricular and supraventricular arrhythmias compared with placebo (OR = 0.32, 95% CI 0.16-0.49; p < 0.001 and OR = 0.42, 95% CI 0.22-0.65; p < 0.001, respectively). Subgroup analysis showed that the effect of magnesium on the incidence of cardiac arrhythmias was not affected by clinical settings and dosage of magnesium. Meta-regression analysis also showed that there was no significant association between the reduction of ventricular arrhythmias and sample size.

CONCLUSION

The results of this meta-analysis study suggest that magnesium sulfate can be used safely and effectively and is a cost-effective way in the prevention of many of ventricular and supraventricular arrhythmias.

Effect of magnesium on arrhythmia incidence in patients undergoing coronary artery bypass grafting

BACKGROUND

Cardiac arrhythmia after coronary artery bypass grafting (CABG) surgery is a common complication of cardiac surgery. The effect of serum magnesium, hypomagnesaemia treatment and prophylactic administration of magnesium in the development and prevention of arrhythmias is controversial and there are many different ideas. This study evaluates the therapeutic effects of magnesium in cardiac arrhythmia after CABG surgery.

METHODS

The clinical trial enrolled 250 patients who underwent CABG. Based on the initial serum levels of magnesium, patients were divided into two groups: hypomagnesium and normomagnesium. Based on bioethics committee requirements, patients in the hypo-magnesium group received magnesium treatments until they attained normal magnesium blood levels. Both groups underwent CABG with normal blood levels of magnesium. After surgery, each group was randomly divided into two subgroups: one subgroup received a bolus dose of magnesium sulphate (30 mg/kg in 5 min) and the other subgroup received a placebo. Subgroups were under observation in the intensive care unit for 3 days and arrhythmias were recorded. Data from all four subgroups were analysed statistically and interpreted.

RESULTS

The results of this study showed that the occurrence of arrhythmia was not significantly different among subgroups (P > 0.05). There was no significant relationship between blood levels of magnesium and arrhythmia during the 3 days post-surgery (P > 0.05).

CONCLUSION

The results of this study showed that magnesium sulphate administration did not significantly improve the incidence of arrhythmias in hypo- and normo-magnesium patients after CABG. There was no significant correlation between post-operative serum levels of magnesium and arrhythmia during 3 days.

Magnesium supplementation: Pharmacokinetics in cardiac surgery patients with normal renal function

BACKGROUND

Intravenous magnesium is routinely administered in intensive care units (ICU) to treat arrhythmias after cardiothoracic surgery. There are no data on the pharmacokinetics of continuous magnesium infusion therapy.

OBJECTIVE

To investigate the pharmacokinetics of continuous magnesium infusion, focusing on serum and urinary magnesium concentration, volume of distribution and half-life.

METHODS

We administered a 10 mmol bolus of magnesium-sulfate followed by a continuous infusion of 3 mmol/h for 12 h in twenty cardiac surgery patients. We obtained blood and urine samples prior to magnesium administration and after one, six, and 12 h.

RESULTS

Median magnesium levels increased from 1.09 (IQR 1.00-1.23) mmol/L to 1.59 (1.45-1.76) mmol/L after 60 min (p < .001), followed by 1.53 (1.48-1.71) and 1.59 (1.48-1.76) mmol/L after 6 and 12 h. Urinary magnesium concentration increased from 9.2 (5.0-13.9) mmol/L to 17 (13.6-21.6) mmol/L after 60 min (p < .001). Cumulative urinary magnesium excretion was 28 mmol (60.9% of the dose given). The volume of distribution was 0.25 (0.22-0.30) L/kg. There were no episodes of severe hypermagnesemia (≥3 mmol/L).

CONCLUSION

Combined bolus and continuous magnesium infusion therapy leads to a significant and stable increase in magnesium serum concentration despite increased renal excretion and redistribution.

Magnesium status and magnesium therapy in cardiac surgery: A systematic review and meta-analysis focusing on arrhythmia prevention

PURPOSE

To investigate magnesium as prophylaxis or treatment of postoperative arrhythmias in cardiac surgery (CS) patients. To assess impact on biochemical and patient-centered outcomes.

MATERIALS AND METHODS

We searched MEDLINE, CENTRAL and EMBASE electronic databases from 1975 to October 2015 using terms related to magnesium and CS. English-Language RCTs were included involving adults undergoing CS with parenterally administered magnesium to treat or prevent arrhythmias, compared to control or standard antiarrythmics. We extracted incidence of postoperative arrhythmias, termination following magnesium administration and secondary outcomes (including mortality, length of stay, hemodynamic parameters, biochemistry).

RESULTS

Thirty-five studies were included, with significant methodological heterogeneity. Atrial fibrillation (AF) was most commonly reported, followed by ventricular, supraventricular and overall arrhythmia frequency. Magnesium appeared to reduce AF (RR 0.69, 95% confidence interval (95%CI) 0.56-0.86, p=0.002), particularly postoperatively (RR 0.51, 95%CI 0.34-0.77, p=0.003) for longer than 24h. Maximal benefit was seen with bolus doses up to 60mmol. Magnesium appeared to reduce ventricular arrhythmias (RR=0.46, 95%CI 0.24-0.89, p=0.004), with a trend to reduced overall arrhythmias (RR=0.80, 95%CI 0.57-1.12, p=0.191). We found no mortality effect or significant increase in adverse events.

CONCLUSIONS

Magnesium administration post-CS appears to reduce AF without significant adverse events. There is limited evidence to support magnesium administration for prevention of other arrhythmias.

Database evaluation of the association between serum magnesium levels and the risk of atrial fibrillation in the community

BACKGROUND

In population studies, mild hypomagnesemia, determined by a single measurement, was associated with incident atrial fibrillation, over ~20 years of follow-up. We sought to determine whether mild (≤ 1.7 mg/dL) and moderate (≤ 1.5mg/dL) hypomagnesemia are temporally associated with increased incidence of atrial fibrillation (AF) in the community.

METHODS

Health Maintenance Organization (HMO) database cohort study including beneficiaries with ≥ 1 serum magnesium measurement between 2004 and 2013. The follow-up period was defined from the first magnesium measurement to first listing in an AF registry (for cases) and December 2013 or date of death or loss to follow-up (for controls). We analyzed the association between serum magnesium quintiles, as well as the above clinically relevant hypomagnesemia thresholds, and incident AF using Cox proportional hazard regression analysis, adjusting for confounders. The association between serum magnesium and AF occurring within 3 months was also examined.

RESULTS

Among 162,162 subjects, 2228 (1.4%) developed AF over a median follow-up of 25.3 months. Compared to the middle quintile the lowest magnesium quintile (≤ 1.9 mg/dL) had a significantly higher risk of AF (HR, 1.21; 95% CI: 1.07-1.37). Increased AF risk was also associated with mild (HR, 1.44; 95% CI: 1.20-1.73) and moderate hypomagnesemia (HR, 1.57; 95% CI: 1.14-2.15). No association was found when limiting the follow-up period to 3 months.

CONCLUSIONS

In our study, hypomagnesemia was associated with incident AF over prolonged but not short-term follow-up periods, suggesting that this association may not be causal.

Increases in intravenous magnesium use among hospitalized patients: an institution cross-sectional experience

BACKGROUND

Among hospitalized patients, indications for the measurement of magnesium levels and treatment of hypomagnesemia with intravenous magnesium are not well defined. Recently, there have been reports of worldwide shortages of intravenous magnesium sulphate.

OBJECTIVE

To examine secular trends in the administration of intravenous magnesium on hospital wards at a tertiary care institution. The secondary objective is to identify factors associated with magnesium use among admitted patients.

METHODS

Retrospective cross-section review of hospitalized patients at a single Canadian tertiary care center. Utilization of non-parental nutrition intravenous magnesium from 2003 to 2013 stratified by hospital ward was examined. In addition, patient level data from select wards (including medical and surgical services) was examined at early and more recent time period (4/2006 versus 4/2013).

RESULTS

Among the 248,329 hospitalized patients, intravenous magnesium use increased by 2.86 fold from 2003 to 2013. Not all wards had an increase whereas some had nearly a 10 fold increase in use. In the sample (n = 769), (adjusting for admission magnesium level, presence of an indication for intravenous magnesium, ward location, comorbidity and demographics) intravenous magnesium administration was higher (25.8 % versus 5.5 %) in 2013 versus 2006 (OR 13.91 (95 % CI, 6.21-31.17, p < 0.001). Despite this increase in intravenous magnesium administration, <3 % of patients were admitted on oral magnesium in 2006 and 2013. For patients receiving intravenous magnesium only a minority were discharged on oral therapy despite low levels.

CONCLUSIONS

This center has witnessed a considerable increase in the use of in-hospital intravenous magnesium over the last 6 years that cannot be explained for by medical indications. The risks and benefits of this therapy deserve further study. If this change in practice is representative of other North American hospitals, it may be responsible for recent drug shortages.

Magnesium in man: implications for health and disease

Magnesium (Mg(2+)) is an essential ion to the human body, playing an instrumental role in supporting and sustaining health and life. As the second most abundant intracellular cation after potassium, it is involved in over 600 enzymatic reactions including energy metabolism and protein synthesis. Although Mg(2+) availability has been proven to be disturbed during several clinical situations, serum Mg(2+) values are not generally determined in patients. This review aims to provide an overview of the function of Mg(2+) in human health and disease. In short, Mg(2+) plays an important physiological role particularly in the brain, heart, and skeletal muscles. Moreover, Mg(2+) supplementation has been shown to be beneficial in treatment of, among others, preeclampsia, migraine, depression, coronary artery disease, and asthma. Over the last decade, several hereditary forms of hypomagnesemia have been deciphered, including mutations in transient receptor potential melastatin type 6 (TRPM6), claudin 16, and cyclin M2 (CNNM2). Recently, mutations in Mg(2+) transporter 1 (MagT1) were linked to T-cell deficiency underlining the important role of Mg(2+) in cell viability. Moreover, hypomagnesemia can be the consequence of the use of certain types of drugs, such as diuretics, epidermal growth factor receptor inhibitors, calcineurin inhibitors, and proton pump inhibitors. This review provides an extensive and comprehensive overview of Mg(2+) research over the last few decades, focusing on the regulation of Mg(2+) homeostasis in the intestine, kidney, and bone and disturbances which may result in hypomagnesemia.

Anticoagulation strategies for the management of postoperative atrial fibrillation

Patients undergoing thoracic and cardiac procedures are at the highest risk for postoperative atrial fibrillation (POAF). POAF is associated with poor short-term and long-term outcomes, including high rates of early and late stroke, and late mortality. Patients with POAF that persists for longer than 48 hours should be anticoagulated on warfarin. Three new oral anticoagulants are available for the treatment of nonvalvular atrial fibrillation and have been found to be as efficacious or superior to warfarin in the prevention of stroke in high-risk patients, with similar to lower rates of major bleeding, and lower rates of intracranial hemorrhage.

Magnesium supplementation reduces postoperative arrhythmias after cardiopulmonary bypass in pediatrics: a metaanalysis of randomized controlled trials

Postoperative arrhythmia (POA) is the most common complication encountered after cardiopulmonary bypass (CPB). The preventive effect of magnesium in POA has been confirmed by metaanalyses in adults, but less is known in pediatric patients. A metaanalysis of published trials was conducted to examine the efficacy of magnesium supplementation in POA prevention among pediatric patients undergoing CPB. Relevant trials were identified from electronic databases (Medline, Embase, Web of Science, and Cochrane library). Pooled relative risk (RR) and 95 % confidence intervals (CI) were calculated using Mantel-Haenszel random-effects models, and heterogeneity was determined qualitatively according to I (2) and chi-squared statistical analyses. Among 121 potentially relevant studies, five randomized controlled trials met the inclusion criteria, resulting in a pooled total of 348 participants. Compared with placebo, magnesium supplementation decreased the incidence of arrhythmia after CPB in pediatric patients by 66 % (RR, 0.34; 95 % CI, 0.18-0.65; P = 0.001), with no heterogeneity between trials (heterogeneity P = 0.68; I (2) = 0 %). Magnesium supplementation significantly reduces the incidence of postoperative arrhythmias in pediatric patients undergoing CPB. Although the findings encourage the use of magnesium as an alternative to postoperative arrhythmias after CPB in pediatric patients, higher-quality randomized clinical trials are necessary before the findings can be generalized.

Perioperative Systemic Magnesium to Minimize Postoperative Pain

Background:

Systemic magnesium has been used to minimize postoperative pain with conflicting results by clinical studies. It remains unknown whether the administration of perioperative systemic magnesium can minimize postoperative pain. The objective of the current investigation was to evaluate the effect of systemic magnesium on postoperative pain outcomes.

Methods:

A wide search was performed to identify randomized controlled trials that evaluated the effects of systemic magnesium on postoperative pain outcomes in surgical procedures performed under general anesthesia. Meta-analysis was performed using a random-effect model. Publication bias was evaluated by examining the presence of asymmetric funnel plots using Egger regression.

Results:

Twenty randomized clinical trials with 1,257 subjects were included. The weighted mean difference (99% CI) of the combined effects favored magnesium over control for pain at rest (≤4 h, −0.74 [−1.08 to −0.48]; 24 h, −0.36 [−0.63 to −0.09]) and with movement at 24 h, −0.73 (−1.37 to −0.1). Opioid consumption was largely decreased in the systemic magnesium group compared with control, weighted mean difference (99% CI) of −10.52 (−13.50 to −7.54) mg morphine IV equivalents. Publication bias was not present in any of the analysis. Significant heterogeneity was present in some analysis, but it could be partially explained by the sole intraoperative administration of magnesium compared with the intraoperative and postoperative administration. None of the studies reported clinical toxicity related to toxic serum levels of magnesium.

Conclusion:

Systemic administration of perioperative magnesium reduces postoperative pain and opioid consumption. Magnesium administration should be considered as a strategy to mitigate postoperative pain in surgical patients.

Magnesium adjunctive therapy in atrial arrhythmias

Magnesium (Mg) is an important intracellular ion with cardiac metabolism and electrophysiologic properties. A large percentage of patients with arrhythmias have an intracellular Mg deficiency, which is out of line with serum Mg concentrations, and this may explain the rationale for Mg's benefits as an atrial antiarrhythmic agent. A current limitation of antiarrhythmic therapy is that the potential for cardiac risk offsets some of the benefits of therapy. Mg enhances the balance of benefits to harms by enhancing atrial antiarrhythmic efficacy and reducing antiarrhythmic proarrhythmia potential as well as providing direct antiarrhythmic efficacy when used as monotherapy in patients undergoing cardiothoracic surgery.