Postoperative oral amiodarone as prophylaxis against atrial fibrillation after coronary artery surgery

OBJECTIVE: To assess the prophylactic effect of postoperative oral amiodarone on the incidence and severity of atrial fibrillation (AF) after coronary artery surgery. DESIGN: Prospective, randomized, blinded, controlled study. SETTING: University hospital. PARTICIPANTS: Patients who had coronary artery surgery (n = 200). INTERVENTIONS: Patients in group 1 (n = 100) received oral amiodarone, 15 mg/kg, 4 hours after arrival in the intensive care unit, followed by 7 mg/kg/d until hospital discharge. Patients in group 2 (n = 100) received placebo. MEASUREMENTS AND MAIN RESULTS: Incidence, duration, and recurrence of new episodes of AF and maximal ventricular rate response were recorded from day 0 until hospital discharge. Side effects related to amiodarone and complications induced by new-onset AF were noted. The incidence of new-onset AF (12% v 25%) and maximal ventricular rate response (120 +/- 21 beats/min v 135 +/- 24 beats/min) were significantly lower in the amiodarone group. There were no side effects related to the administration of amiodarone. The incidence of complications induced by AF was comparable between the 2 groups. CONCLUSION: Postoperative prophylactic oral amiodarone after coronary artery surgery is safe and effective in reducing the incidence of new-onset AF and maximal ventricular rate response.     

Intravenous amiodarone or magnesium sulphate is not cost-beneficial prophylaxis for atrial fibrillation after coronary artery bypass surgery

Our aims were to examine whether the administration of amiodaroneor magnesium sulphate after coronary artery bypass graft surgery(CABG) could reduce the occurrence of atrial fibrillation, andto identify the risk factors associated with atrial fibrillationafter CABG. Patients scheduled for elective CABG (n=155) wereallocated randomly, in a controlled double-blind study, to receiveimmediately after surgery a 72-h infusion of amiodarone (900 mgper 24 h), magnesium (4 g per 24 h) or placebo(0.9% NaCl; 50 ml per 24 h) intravenously. A 72-hHolter ECG was recorded concomitantly. The primary end-pointwas the prevention of atrial fibrillation; its onset was consideredas prophylactic failure. An interim safety analysis was performedin 147 patients. The cumulative occurrence of atrial fibrillationwas 27% in the placebo group, 14% in the amiodarone group (P=0.14)and 23% in the magnesium group (P=0.82). Although amiodaronedelayed the onset of the first tachyarrhythmic episode (P=0.02),it was associated with the need for longer periods of vasoactivedrug infusion and invasive monitoring and a longer stay in theintensive care unit. Variables associated with the onset ofatrial fibrillation were older age (odds ratio 1.9) and a plasmamagnesium concentration at 24 h of less than 0.95 mmollitre^–1 (odds ratio 6.7). Postoperative administrationof amiodarone reduced the occurrence of atrial fibrillationafter elective CABG surgery, but was associated with a longerduration of cardiovascular instability and longer need for intensivecare; magnesium prophylaxis had no effect. Advanced age anda low plasma magnesium concentration are risk factors for postoperativeatrial fibrillation. Br J Anaesth 2000; 85: 690–5     

Intravenous magnesium sulfate prophylaxis for atrial fibrillation after coronary artery bypass surgery

OBJECTIVE: Atrial fibrillation is a rhythm disorder commonly seen early after coronary artery bypass grafting, and it increases morbidity. METHODS: To investigate the effectiveness of magnesium sulfate in the prophylaxis of atrial fibrillation, we conducted a prospective, randomized, placebo-controlled clinical study on 200 consecutive patients in whom we performed elective and initial coronary artery bypass grafting operations. In each group 50% of patients underwent beating-heart operations. In the treatment group 100 patients (76 men and 24 women; mean age, 57.63 +/- 9.68 years) received 24.34 mEq (3 g) of magnesium sulfate in 100 mL of saline solution that was administered over 2 hours (50 mL/h) preoperatively, perioperatively, and at postoperative days 0, 1, 2, and 3. In the control group 100 patients (74 men and 26 women; mean age, 59.96 +/- 9.29 years) received only 100 mL of saline solution according to the same administration schedule as the treatment group. RESULTS: Atrial fibrillation developed in 15 patients from the treatment group and in 16 patients from the control group. The arrhythmia developed after 37.87 +/- 12.76 and 45.26 +/- 15.27 hours in the treatment and control groups, respectively. Although a significant relationship was found between low magnesium sulfate levels and increased incidence of atrial fibrillation (P <.05), when the incidence of postoperative atrial fibrillation is concerned, no significant difference was found between the 2 groups (P >.05). Also, no significant difference was found between operations with cardiopulmonary bypass and beating-heart operations in terms of atrial fibrillation incidence (P >.05). However, atrial fibrillation extended the duration of hospital stay in both groups (P <.05). CONCLUSION: Our findings indicate that magnesium sulfate infusion alone is not sufficient for the prophylaxis of atrial fibrillation.     

Intravenous amiodarone for prevention of atrial fibrillation after coronary artery bypass grafting

BACKGROUND: Atrial fibrillation occurs in 10% to 40% of patients who undergo coronary artery bypass grafting. This prospective study assesses the safety and efficacy of low-dose intravenous amiodarone in the prevention of atrial fibrillation after coronary artery bypass grafting. METHODS: One hundred forty patients were randomly divided into two groups: an amiodarone group (n = 74) receiving intravenous amiadarone in a loading dose of 150 mg and maintenance dose of 0.4 mg x kg(-1) x h(-1) for 3 days before and 5 days after operation and a control group (n = 76) receiving matching infusions of 5% glucose solution. RESULTS: Atrial fibrillation occurred in 9 (12%) of the amiodarone group patients and in 26 (34%) of the control group patients during hospitalization (p < 0.01). The maximum ventricular rate during atrial fibrillation was significantly slower in the amiodarone group (107 +/- 21) than in the control group (138 +/- 24 beats per minute, p < 0.01). The duration of atrial fibrillation in the amiodarone group (1.1 +/- 1.2 hours) was significantly shorter than that in the control group (3.2 +/- 1.3 hours, p = 0.01). The two groups had no significant differences in incidence of major morbidity (8 of 74 versus 8 of 76 in amiodarone and control groups, respectively) or mortality (4 of 74 versus 5 of 76). However, the control group had significantly longer intensive care unit stays (132 +/- 24 versus 111 +/- 19 hours, p < 0.01). CONCLUSIONS: Perioperative low-dose intravenous amiodarone significantly reduces the incidence, ventricular rate, and duration of atrial fibrillation after coronary artery bypass grafting. Furthermore, low-dose intravenous amiodarone is well tolerated and does not increase the risk of intraoperative or postoperative complications.     

小剂量胺碘酮预防冠状动脉旁路移植术后心房纤颤

目的 评价小剂量胺碘酮对冠状动脉旁路移植术后心房纤颤的预防效果、耐受性和安全性。方法 对1998至1999年235例冠状动脉旁路移植术后病人进行回顾性研究分析，其中对照组155例予常规药物，试验组80例合用小剂量胺碘酮。结果 常规药物治疗组21．93％出现心房纤颤，而小剂量胺碘酮预防用药组10％出现心房纤颤(P=0．024)。小剂量胺碘酮致心律失常3例，无甲状腺及肺部并发症发生。结论 预防应用小剂量胺碘酮能明显降低术后心室率，减少心房纤颤发生率，延迟发作，缩短持续时间，促进心房纤颤转复，同时改善心功能。小剂量胺碘酮毒副作用低于大剂量胺碘酮，尤其适用于缺血性心脏病合并心肌梗死及左心功能不全者。     

Effects of amiodarone and thoracic epidural analgesia on atrial fibrillation after coronary artery bypass grafting

OBJECTIVE: This study was designed to assess the effects of a perioperative dosing regimen of amiodarone administration, high thoracic epidural anesthesia (TEA), or a combination of the 2 regimens on atrial fibrillation (AF) after coronary artery bypass grafting (CABG). DESIGN AND SETTING: The study was prospective, controlled, and randomized and was performed in a tertiary health care center associated with a university. PARTICIPANTS: One hundred sixty-three patients scheduled for coronary artery bypass graft surgery. INTERVENTIONS: In this 2 x 2 factorial-designed study the patients were randomized to 1 of 4 regimens in which group E had perioperative TEA, group E+A had TEA and amiodarone, group A had amiodarone, and group C served as control. The epidural catheter was inserted at T1-3 the day before surgery. TEA groups received TEA for 96 hours. The amiodarone regimen consisted of a single loading dose of 1,800 mg of amiodarone orally. Intravenous infusion of amiodarone was started after induction of anesthesia and was administered at 900 mg over 24 hours for the subsequent 3 days. MEASUREMENTS AND MAIN RESULTS: AF was documented using Holter monitoring. In group E 22 of 44 (50%), in group E+A 10 of 35 (28.6%), in group A 10 of 36 (27.8%), and in the control group 20 of 48 (41.7%) patients developed AF (odds ratio amiodarone/nonamiodarone 0.47 [0.24-0.90]; P = 0.02). CONCLUSIONS: The perioperative amiodarone regimen used in this study was effective in reducing the incidence of AF after CABG while TEA was not.     

Prophylaxis of atrial fibrillation with magnesium sulfate after coronary artery bypass grafting

Ninety-nine consecutive consenting patients were prospectively entered into a randomized, double-blind, placebo-controlled trial to determine the efficacy of postoperative magnesium therapy on the incidence of cardiac arrhythmias after elective coronary artery bypass grafting. No patient had documented or suspected arrhythmias preoperatively. Forty-nine patients received 178 mEq of magnesium given over the first 4 postoperative days, and 50 patients received only placebo. The clinical characteristics of both groups were similar. The preoperative mean serum magnesium concentration was similar in both study (1.90 mEq/L) and placebo (1.90 mEq/L) groups. The mean postoperative serum magnesium concentration in study patients was significantly elevated over postoperative days 1 through 4 when compared with preoperative levels (p less than 0.001). The postoperative mean serum magnesium concentration in control patients declined and remained significantly depressed through postoperative day 3 (p less than 0.001), but increased to preoperative levels by postoperative day 4. The mean serum magnesium concentration was significantly greater in the study patients as compared with the control patients over postoperative days 1 through 4 (p less than 0.001). Although there was no significant difference between groups with respect to episodes of ventricular arrhythmias, there was a significant decrease in the number of episodes of atrial fibrillation in the group receiving magnesium therapy (p less than 0.02). There were no recognized adverse effects of magnesium therapy. Prophylactic magnesium administration seems to lessen the incidence and severity of atrial fibrillation after coronary artery bypass grafting.     

Combination of sotalol and magnesium prevents atrial fibrillation after coronary artery bypass grafting

BACKGROUND: Atrial fibrillation (AF) is a common complication reported in 20% to 40% of patients after coronary operations. Sotalol alone and magnesium alone have been shown to partially decrease the incidence of AF. The goal of this study was to evaluate the efficacy of these two pharmacological agents, used alone or in combination, to reduce postoperative AF. METHODS: Two hundred seven consecutive coronary artery bypass patients (mean age 62 +/- 11 years) were randomized to receive sotalol alone (80 mg twice daily for 5 days starting from the morning of the first postoperative day) (group S), magnesium alone (1.5 g daily for 6 days starting in the operating room just before cardiopulmonary bypass) (group M), both pharmacologic agents at the same dosages (group S+M), or no antiarrhythmic agents (group CTR). All patients with an ejection fraction less than 0.40 were excluded. RESULTS: The incidence of postoperative AF was 11.8% (6/51) in the S group, 14.8% (8/54) in the M group, 1.9% (1/52) in the S+M group, and 38% (19/50) in the CTR group. The following differences were significant: group CTR versus groups S, M, and S+M with values of p = 0.002, p = 0.007 and p < 0.0001, respectively; and group S+M versus groups S and M with p = 0.04 and p = 0.01, respectively. CONCLUSIONS: Incidence of AF after coronary operation was significantly reduced by the administration of sotalol alone and magnesium alone; more importantly, the incidence was further reduced by combining these agents.     

Predictors of atrial fibrillation after off-pump coronary artery bypass graft surgery

Background: Postoperative atrial fibrillation (AF) is one of the most commoncomplications after cardiothoracic surgery and is associatedwith an increased risk of stroke, and longer hospital stay.The pathophysiology of postoperative AF is uncertain, and itsprevention remains unsatisfactory. Many previous studies haveexamined the predictors of AF after on-pump coronary arterybypass graft surgery (CABG), but there are few reports afteroff-pump CABG. Methods: The aim of the present prospective observational study, in which296 consecutive patients were enrolled, was to elucidate thepredictors of AF after off-pump CABG. The association of perioperativefactors with AF was investigated using univariate analysis.Significant variables were included into a stepwise logisticregression model to ascertain their independent influence onthe occurrence of AF. Results: The incidence of AF was 32%. AF prolonged the time until patientswere fit for discharge by 3 days (P < 0.01). Stepwise multivariateanalysis identified increasing age [odds ratio (OR) 1.44 per10-yr increase; 95% confidence interval (CI) 1.06–1.95],intraoperative average core temperature (OR 1.64; 95% CI 1.05–2.56),the average cardiac index in the intensive care unit (OR 0.37;95% CI 0.19–0.71), and intraoperative fluid balance (OR0.96 per 100-ml increase; 95% CI 0.93–0.99) as independentpredictors of postoperative AF. Conclusion: Our present findings indicate that ageing, the intraoperativefluid balance, and postoperative cardiac index are associatedwith the onset of AF after off-pump CABG.     

Predictors of atrial fibrillation after off-pump coronary artery bypass graft surgery

OBJECTIVE: Atrial fibrillation is the most common complication after coronary artery bypass graft surgery. This arrhythmia may lead to hemodynamic compromise, prolonged hospitalization, and increased risk for cerebral thromboembolism. Older age is the only variable consistently associated with the development of postoperative atrial fibrillation; however, no strong predictive model exists. The purpose of this study was to identify perioperative characteristics associated with new-onset atrial fibrillation in patients undergoing off-pump coronary artery bypass grafting. DESIGN: Prospective, observational. SETTING: University tertiary care hospital. PARTICIPANTS: One hundred sixty consecutive patients undergoing off-pump coronary artery bypass grafting. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Incidence of postoperative atrial fibrillation was the major outcome. Atrial fibrillation occurred in 33 patients (20.6%). Multivariate analysis identified reintervention (odds ratio 26.8), revascularization of the ramus medianus (odds ratio 3.9), and age (odds ratio 1.069 per year) as the only independent predictors of postoperative atrial fibrillation. All patients were in sinus rhythm at hospital discharge. One hospital death was noted. CONCLUSIONS: Despite the less invasive approach, the incidence of postoperative atrial fibrillation is high after off-pump coronary artery bypass grafting. Older age, grafting of the ramus medianus, and a redo operation were predictors of new-onset postoperative atrial fibrillation. It is possible that left atrial stretching with heart dislocation during revascularization of the lateral wall could lead to postoperative atrial fibrillation.     

Predicting the risk of atrial fibrillation after coronary artery bypass surgery

Atrial fibrillation (AF) is the most common arrhythmia, with an incidence of 17–33%, after coronary artery bypass grafting (CABG) and it increases the cost of operative treatment. β‐Blocker therapy reduces markedly the incidence of postoperative AF. The more effective preventive methods, e.g. amiodarone therapy or atrial pacing, are not cost‐effective for all the patients. Thus, identification of patients at high risk of AF after CABG would be helpful. This review summarizes the predictors of postoperative AF and the current methods for risk stratification. In summary, identification of the patients at high risk of postoperative AF remains a challenge. The clinical usefulness of most of the conventional factors, e.g. age or history of AF, is low. Even attempts to build logistic regression models based on the pre‐ and intraoperative variables have failed to provide powerful predictors for postoperative AF after CABG. From the new predictors, the P‐wave duration in signal‐averaged ECG looks promising. Sensitivity and negative predictive value are high, positive predictive value remains low, which limits its usefulness. Contrary, even detailed analysis of standard 12‐lead ECG or measure of heart rate variability has failed to provide useful information for risk stratification. A new method for risk stratification has been developed in our centre. The diagnostic accuracy of high‐rate atrial pacing seems to be sufficient to identify a group of patients to whom prophylactic treatment could be proactively targeted. Further experience is, however, warranted to verify significance of this method in everyday clinical practice.     

Intravenous magnesium for prevention of atrial fibrillation after coronary artery bypass surgery: a systematic review and meta-analysis

Atrial fibrillation (AF) is one of the most common complications after coronary artery bypass surgery. The objective of this study was to assess the effectiveness of intravenous magnesium in preventing postoperative atrial fibrillation. A meta-analysis of eight identified randomized controlled trials, reporting comparisons between magnesium and control was undertaken. The primary outcome was incidence of postoperative atrial fibrillation. Our review revealed that use of intravenous magnesium is associated with a significant reduction in the incidence of atrial fibrillation after coronary artery bypass surgery, with a relative risk of 0.64 (95% confidence interval = 0.47, 0.87, and p = 0.004).     

Predictors of atrial fibrillation occurrence after coronary artery bypass graft surgery

Purpose  

Postoperative atrial fibrillation (AF) is the most common complication after coronary artery bypass graft (CABG) surgery, with an incidence of 20%–50%. The objective of this study was to investigate perioperative risk factors of postoperative sustained AF by the way of logistic regression analysis.     

Predicting the risk of atrial fibrillation after coronary artery bypass surgery

Atrial fibrillation (AF) is the most common arrhythmia, with an incidence of 17-33%, after coronary artery bypass grafting (CABG) and it increases the cost of operative treatment. beta-Blocker therapy reduces markedly the incidence of postoperative AF. The more effective preventive methods, e.g. amiodarone therapy or atrial pacing, are not cost-effective for all the patients. Thus, identification of patients at high risk of AF after CABG would be helpful. This review summarizes the predictors of postoperative AF and the current methods for risk stratification. In summary, identification of the patients at high risk of postoperative AF remains a challenge. The clinical usefulness of most of the conventional factors, e.g. age or history of AF, is low. Even attempts to build logistic regression models based on the pre- and intraoperative variables have failed to provide powerful predictors for postoperative AF after CABG. From the new predictors, the P-wave duration in signal-averaged ECG looks promising. Sensitivity and negative predictive value are high, positive predictive value remains low, which limits its usefulness. Contrary, even detailed analysis of standard 12-lead ECG or measure of heart rate variability has failed to provide useful information for risk stratification. A new method for risk stratification has been developed in our centre. The diagnostic accuracy of high-rate atrial pacing seems to be sufficient to identify a group of patients to whom prophylactic treatment could be proactively targeted. Further experience is, however, warranted to verify significance of this method in everyday clinical practice.     

Perioperative magnesium supplementation to prevent atrial fibrillation after off-pump coronary artery surgery: a randomized controlled study

OBJECTIVE: Atrial fibrillation is a common complication after cardiac surgery. Magnesium is an effective and safe antiarrhythmic agent for arrhythmias that develop after cardiac surgery. The authors performed a study to evaluate the role of perioperative magnesium for prophylaxis of atrial fibrillation after off-pump coronary artery surgery. DESIGN: Randomized controlled study. SETTING: University teaching hospital. PARTICIPANTS: One hundred sixty consecutive patients undergoing elective, isolated, off-pump coronary artery bypass grafting were prospectively randomized into 2 groups. INTERVENTIONS: Patients in the magnesium group (n = 80) received a 2.5-g (20 mEq) magnesium sulphate infusion intraoperatively over 30 minutes, and the placebo group (n = 80) received normal saline solution. MEASUREMENTS AND MAIN RESULTS: Postoperative atrial fibrillation occurred in 16 of 80 patients (20%) in the magnesium group and in 18 of 80 (22.5%) in the placebo group (p = 0.9). CONCLUSION: The use of 2.5 g of intraoperative magnesium showed no effect in preventing atrial fibrillation after off-pump coronary artery bypass.     

Selective prophylaxis of atrial fibrillation with amiodarone after cardiac surgery

AIM: Atrial fibrillation (AF) is common after cardiac surgery, but prophylaxis for patients especially prone to developing this arrhythmia has not been studied to date. We investigated amiodarone as prophylaxis for AF in selected patients after open-heart surgery. METHODS: In the first stage we studied a group of 204 consecutive cardiac surgery patients and devised a formula from some of the known risk factors of AF for each sex to serve as a predictor model. In this first group we were able to quantify the probability of developing this arrhythmia. In the second stage we applied this formula to a group of 231 consecutive cardiac surgery patients and then selectively treated the high-risk patients for AF: 25 men (16.1%) and 29 women (53.7%). In the first 24 h of treatment with amiodarone, 22 patients (10 men and 12 women) were excluded from the study due to sinus bradycardia. Therapy consisted of amiodarone 900 mg intravenously every 24 h for the first 2 postoperative days, followed by 600 mg intravenously every 24 h until discharge from the Intensive Care Unit. RESULTS: Expected AF in males fell from 34.4% (52/151) in the observation group to 11% (17/155) in the treated group, and in females from 50.9% in the observation group (27/53) to 9.3% (5/54) in the treated group (P<0.001). CONCLUSIONS: Patient-selective prophylaxis of AF with amiodarone can be a highly effective measure.     

Intraoperative amiodarone as prophylaxis against atrial fibrillation after coronary operations

BACKGROUND: New onset of atrial fibrillation is a frequent complication after coronary artery bypass grafting and is a major cause of postoperative morbidity. Preoperative oral treatment with amiodarone hydrochloride has been shown to be efficacious as prophylaxis. The present study investigated whether intraoperative use of intravenous amiodarone has a preventive effect on the incidence of atrial fibrillation after coronary revascularization. METHODS: In a prospective study, 150 consecutive patients (mean age, 63 +/- 8 years; 132 men and 18 women) undergoing coronary artery bypass grafting were randomly assigned to one of three groups. Two groups received different doses of intravenous amiodarone (group I, 300-mg bolus and 20 mg x kg(-1) x day(-1) for 3 days; group II, 150-mg bolus and 10 mg x kg(-1) x day(-1) for 3 days) after aortic cross-clamping and one group, placebo (group III). Continuous electrocardiographic online monitoring was performed for 10 days. Arrhythmias were analyzed with respect to type, frequency, duration, and clinical relevance. RESULTS: New onset of atrial fibrillation occurred in 24% of patients in group I, 28% in group II, and 34% in group III (p = not significant). Atrial fibrillation with a rapid ventricular response (>120 beats per minute) was significantly more frequent in the control group (group I, 14%; group II, 24%; group III, 32%; p < 0.05, group I versus group III) and appeared significantly earlier (group I, day 4.3 +/- 2.5; group II, day 4.8 +/- 2.9; group III, day 2.6 +/- 1.3; p < 0.05, group III versus groups I and II). Temporary atrial pacing because of bradycardia (<60 beats per minute) was necessary significantly more often in group I (group I, 48%; group II, 40%; group III, 28%; p < 0.05, group I versus group III). Early mortality rate (group I, 4%; group II, 2%; group III, 4%), rate of perioperative complications (group I, 14%; group II, 20%; group III, 14%), and duration of hospital stay (group I, 14.0 days; group II, 14.4 days; group III, 14.7 days) were not different between groups. CONCLUSIONS: Intraoperative prophylactic use of amiodarone does not prevent new onset of atrial fibrillation in patients undergoing coronary artery bypass grafting and had no effect on outcome. Therefore, intraoperative prophylactic treatment with amiodarone at the tested doses does not appear to be justified.