The relation between blood and tissue magnesium levels and development of atrial fibrillation after coronary artery bypass surgery

Abstract

Objective: Atrial fibrillation (AF) is a common complication of cardiovascular surgery and its mechanisms are not well understood. The aim of our study was a prospective investigation of the relationship between AF development and tissue or blood magnesium levels. Methods: This prospective observational study evaluated 20 patients undergoing elective initial coronary artery bypass graft (CABG) surgery. Right atrial appendage and skeletal muscle samples were obtained for tissue magnesium level analysis before, during (at 60 th minute) and 30 minutes after cardiopulmonary bypass (CPB) with simultaneous blood samples. Daily measurements of blood Mg levels and continuous monitoring for AF were performed for 7 postoperative days. Statistical analyses were performed using ANOVA, independent samples t and Chi-square tests. Results: AF developed in 5 out of 20 patients during postoperative period (25%). Patients with or without AF did not differ in terms of tissue and blood magnesium levels during and early after CPB and during 7 days after the operation. Blood magnesium levels were significantly higher in the whole study population on postoperative days 3 through 7 (day 3 -1.13±0.11 mmol/L; day 4-, 1.18±0.07 mmol/L; day 5-1.15±0.10 mmol/L; day 6-1.17±0.08 mmol/L; and day 7, 1.22±0.08 mmol/L) compared to day 1 and day 2 (day 1-0.96±0.13 mmol/L and day 2-1.02±0.12 mmol/L; p<0.002 for all comparisons). Conclusion: Although patients with and without AF did not significantly differ with regard to blood and tissue magnesium levels, the coincidence of an early postoperative reduction in magnesium levels in all patients and occurrence of all AF incidences at this time period suggests a potential association deserving further investigation. (Anadolu Kardiyol Derg 2010; 10: 446-51) Key words: Coronary artery bypass grafting, atrial fibrillation, tissue magnesium level, blood magnesium level ÖZET Amaç: Atriyal fibrilasyon (AF), mekanizması halen tam olarak anlaşılmamakla birlikte kardiyovasküler cerrahi sonrası en sık karşılaşılan komplikasyonlardan biridir. Çalışmamızda, prospektif olarak doku ve kan magnezyum seviyelerine ile AF arasındaki ilişkinin araştırılması planlanmıştır. Yöntemler: Bu prospektif gözlemsel çalışmada, elektif koroner arter baypas greft cerrahisi uygulanacak 20 hastanın kardiyopulmoner baypas öncesi, pompanın 60. dakikası, pompadan sonraki 30. dakikada eş zamanlı olarak atriyum dokusu, rektus abdominis kas dokusu ve kan örnekleri, ayrıca postoperatif 7 gün boyunca günlük kan örnekleri alındı ve magnezyum seviyelerine bakıldı. AF postoperatif 7.güne kadar sürekli monitorize edildi. İstatistiksel analizlerde ANOVA, bağımsız örneklem t ve Ki-kare testleri kullanıldı. Bulgular: Postoperatif dönemde 20 hastadan 5'inde AF gelişti (%25). AF gelişen ve gelişmeyen hastalar arasında kardiyopulmoner baypas öncesi, sırası ve sonrasındaki kan ve doku magnezyum düzeyleri ve postoperatif 7 gün boyunca kan magnezyum düzeyleri açısından fark yoktu. Tüm hastalarda ise kan magnezyum düzeyleri 3 ile 7. günler arasında (3. gün ...

Magnesium Adjunctive Therapy in Atrial Arrhythmias

“…Hypomagnesemia is an independent risk factor for POAF, and causes higher atrial myocardial excitability . These findings are supported by studies that report decreased serum Mg levels 3–5 days postcardiac surgery: a period that parallels the time frame for POAF . Intracellular hypomagnesemia may be present despite normal serum levels and should be considered as a contributor to postoperative atrial arrhythmias …”

Pre-operative use of anti-aggregants may reduce atrial fibrillation development rate during coronary bypass surgery

“…Diverse experimental and clinical trials are conducted to reduce post-operative AF development rate and associated complications; however, AF rate still remains to be up to 40% during bypass surgery. The etiology of postoperative AF is not well defined, although recent studies suggest a multi-factorial mechanism, which includes oxidative stress, inflammation, atrial fibrosis, and excessive production of catecholamines, changes in autonomic tone and in the expression of connexins (3,4). By evaluating retrospectively our coronary bypass surgery results, we observed that we did not discontinue preoperatively used anti-aggregants since a long time and that postoperative AF rate was lower than found in coronary literature.…”

Role of Per Operative Use of Intravenous Magnesium in Reducing the Incidence of Per and Post Operative Arrhythmias in Conventional Coronary Artery Bypass Graft Surgery

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