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References 1. Stricker KH, Rothen HU, Fuhrer J (1998) Atrial tachyarrhythmia after cardiac surgery. Int Care Med 24: 645±662 2. Ommen SR, Odell JA, Stanton MS (1997) Atrial arrhythmias after cardiothoracic surgery. N Engl J Med 336: 1429±1434 3. American College of Chest Physicians/ Society of Critical Care Medicine Consensus Conference (1992) Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. Crit Care Med 20: 864±874 4. Donaldson L, Grant IS, Naysmith MR, Thomas JSJ (1998) Acute amiodaroneinduced lung toxicity. Int Care Med 24: 626±630 A. Mayr × H. Knotzer × N. Mutz × W. Hasibeder ( ) Department of Anesthesiology and General Intensive Care Medicine, Division of General and Surgical Intensive Care Medicine, The Leopold Franzens University, A-6020 Innsbruck, Austria e-mail:
[email protected] Tel. 0043 (0) 512 504 2404 Fax: 0043 (0) 512 504 2490
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K.M. Ho
Atrial tachyarrhythmia after cardiac surgery: role of magnesium infusion Received: 23 September 1998 Accepted: 23 November 1998 Sir: I read the recent review article ªAtrial tachyarrhythmia after cardiac surgeryº by Dr. Stricker and his colleagues with great interest [1]. It gave a very comprehensive account of different pharmacological agents in the prevention and treatment of atrial tachyarrhythmia after cardiac surgery. The role of intravenous magnesium in the prevention of postoperative atrial tachyarrhythmia after cardiac surgery has been controversial. Magnesium deficiency is common during and after cardiac surgery in both adults and children [2]. More than half of all atrial tachyarrhythmia after cardiac surgery occur after the first postoperative day. The study by England et al. [3]
showed that the treatment group as a whole who received intravenous magnesium bolus intraoperatively did not have less postoperative tachyarrhythmia. However, those who received magnesium and had been documented normomagnesaemic postoperatively had significantly less atrial tachyarrhythmia compared with those who received magnesium but remained hypomagnesaemic. This study actually suggested that successful correction of hypomagnesaemia can reduce atrial tachyarrhythmia after cardiac surgery. Subsequent randomised controlled studies showed that magnesium is useful in the prevention of atrial tachyarrhythmia after cardiac surgery if it is given by infusion up to 120 h postoperatively [4, 5]. Magnesium is useful in the prevention of atrial tachyarrhythmia after cardiac surgery if the dose used is sufficient to prevent hypomagnesaemia or when it is continuously infused up to 120 h postoperatively rather than given as a single intraoperative bolus.
References 1. Stricker KH, Rothen HU, Fuhrer J (1998) Atrial tachyarrhythmia after cardiac surgery. Intensive Care Med 24: 654±662 2. Satur CM (1997) Magnesium and cardiac surgery. Ann R Coll Surg Engl 79: 349±354 3. England MR, Gordon G, Salem M, Chernow B (1992) Magnesium administration and dysrhythmias after cardiac surgery. a placebo-controlled doubleblind randomised trial. JAMA 268: 2395±2402 4. Wistbacka J, Koistinen J, Karlquist K, Lepojarvi M, Kanhela R, Laurila J, Nissinen J, Pokela R, Solmela E, Ruokoven A, Nuntinen L (1995) Magnesium substition in elective coronary artery surgery: a double-blind clinical study. J Cardiothorac Vasc Anesth 9: 140±146 5. Nurözzler F, Tokgozoglu L, Pasaoglu I, Boke E, Ersoy, Bozer Y (1996) Atrial fibrillation after coronary artery bypass surgery: Predictors and role of MgSO4 replacement. J Card Surg 11: 421±427 K.M. Ho Department of Anaesthesia and Intensive Care, Pamela Youde Eastern Hospital, Chai Wan, Hong Kong e-mail: 106 243.1476@compuserve,com Tel. + 8 52-25 95-71 11 Fax + 8 52-23 70-32 20
K. Stricker H. U. Rothen J. Fuhrer
Reply Received: 16 October 1998 Accepted: 23 November 1998 Sir: Mayr and colleagues mention the systemic inflammatory response syndrome (SIRS) as a risk factor for postoperative atrial tachyarrhythmia. The definition of SIRS is very broad [1]. Many patients after cardiopulmonary bypass meet the criteria for SIRS and we do not know whether it has to be considered as a single clinical entity or as a spectrum of responses related to the surgical procedure. Particular aspects of SIRS after cardiopulmonary bypass could provide us with a rich field of research, as suggested by Taylor [2]. Mayr and colleagues are encouraged by their experience in converting postoperative atrial tachyarrhythmia with infusions of class III anti-arrhythmic agents, mostly amiodarone. However, only the results of a prospective trial should lead to further treatment suggestions, as admitted by Mayr et al. We agree with Dr. Kwok M. Ho that magnesium in the prevention of postoperative atrial tachyarrhythmia is controversial. The studies mentioned by Kwok comprise only small numbers of subjects, and in our opinion these results do not justify the routine prophylactic administration of magnesium. However, in selected patients with known risk factors for hypomagnesemia (e. g. diuretics, alcohol abuse) magnesium substitution may be beneficial.
References 1. American College of Chest Physicians/ Society of Critical Care Medicine Consensus Conference (1992) Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. Crit Care Med 10: 864±874 2. Taylor KM (1996) SIRS ± the systemic inflammatory response syndrome after cardiac operations. Ann Thorac Surg 61: 1607±1608 K. Stricker × H. U. Rothen Institute for Anesthesiology and Intensive Care Medicine, Inselspital, CH-3010 Bern, Switzerland
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J. Fuhrer ( ) Department of Cardiology, University Hospital, Inselspital, CH-3010 Bern, Switzerland Tel. + 41 31 6 32 96 54 Fax + 41 31 6 32 42 99
