Prevention and treatment of atrial fibrillation after cardiac surgery

The incidence of postoperative atrial fibrillation in cardiac surgery is still high despite major advances in anesthetic, pharmacological and surgical techniques. Its precise mechanism is still totally unknown. Postoperative atrial fibrillation increases length of stay as well as hospital costs. Rate of postoperative atrial fibrillation spontaneous conversion is high. Several protocols have been developed for prevention and/or treatment of postoperative atrial fibrillation. Beta-blockers, amiodarone and atrial pacing reduce.atrial fibrillation incidence as compared to placebo. On the other hand, amiodarone and propafenone achieve a high conversion rate of installed postoperative atrial fibrillation. However, among many pharmacological options, the best treatment is still to be defined.     

Malignant ventricular tachyarrhythmias in association with propafenone treatment

During treatment with the class Ic antiarrhythmic agent propafenone, the drug appeared to cause malignant ventricular tachyarrhythmias in five patients. Sudden cardiac death occurred in two of them. Three patients exhibited a transition from non-self-terminating ventricular tachycardia to ventricular fibrillation. In the other two patients electrocardiography during syncope revealed ventricular fibrillation. The observed malignant arrhythmias occurred within the first three days of treatment for chronic complex ventricular ectopic activity. Two of the five patients had markedly impaired left ventricular function. All patients received digoxin and low dose diuretic therapy. In contrast to drug induced arrhythmias encountered with other type I antiarrhythmic agents, the proarrhythmic effects of propafenone were not associated with marked QT prolongation. QRS duration was only slightly affected.     

Randomized controlled trial of remote ischemic preconditioning and atrial fibrillation in patients undergoing cardiac surgery

AIMTo study whether remote ischemic preconditioning (RIPC) has an impact on clinical outcomes, such as post-operative atrial fibrillation (POAF).METHODSThis was a prospective, single-center, single-blinded, randomized controlled study. One hundred and two patients were randomized to receive RIPC (3 cycles of 5 min ischemia and 5 min reperfusion in the upper arm after induction of anesthesia) or no RIPC (control). Primary outcome was POAF lasting for five minutes or longer during the first seven days after surgery. Secondary outcomes included length of hospital stay, incidence of inpatient mortality, myocardial infarction, and stroke.RESULTSPOAF occurred at a rate of 54% in the RIPC group and 41.2% in the control group (P = 0.23). No statistically significant differences were noted in secondary outcomes between the two groups.CONCLUSIONThis is the first study in the United States to suggest that RIPC does not reduce POAF in patients with elective or urgent cardiac surgery. There were no differences in adverse effects in either group. Further studies are required to assess the relationship between RIPC and POAF.     

Randomized placebo-controlled trial on local applications of opioids after hemorrhoidectomy

Background  

Hemorrhoidectomy is associated with considerable postoperative pain. This study assessed whether a small dose of morphine or oxycodone administered in the embedded sponge set in the anus at the end of a hemorrhoidectomy intervention reduced postoperative pain.     

Management of atrial fibrillation after cardiac surgery

A best evidence topic in cardiac surgery was written according to a structured protocol addressing the question ‘for post‐cardiac surgery atrial fibrillation (AF), do clinical outcomes differ between rate or rhythm control strategies?’ Altogether, 2174 papers were found using the reported searches, of which 5 represented the best evidence to answer the clinical question. Hospital length of stay ranged from 5.0 to 13.2 days for rate control and 5.2 to 10.3 days for rhythm control. Freedom from AF at follow up was achieved in 84.2–91 and 84.2–96% in rate and rhythm control groups respectively. Minimal serious adverse events were noted in all studies analysed and there was no difference between rate and rhythm control groups. We conclude that in the management of post‐cardiac surgery, AF, rate control and rhythm control are equivalent in terms of hospital length of stay, freedom from arrhythmia at follow up and complication rates.     

Intravenous propafenone in paroxysmal atrial fibrillation: A randomized,placebo-controlled,double-blind,multicenter clinical trial

Background: Pharmacological conversion of paroxysmal atrial fibrillation is frequently necessary. The aim of this study was to compare intravenous propafenone, a class Ic antiar-rhythmic agent, with placebo in paroxysmal atrial fibrillation (AF) of recent onset (<72 h). Patients and methods: We randomly allocated 75 patients, aged 18 to 70 years, with paroxysmal AF to receive intravenous propafenone (2 mg/kg in 15 min followed by 1 mg/kg in 2 h) or the matching placebo. Patients were followed for 3 h. Exclusion criteria were the presence of one of the following: clinical heart failure, recent acute myocardial infarction, hypotension, atrioventricular block, Wolff-Parkinson-White syndrome, or current treatment with antiarrhythmic agents or digitalis. Results: No sign of heart disease was found in 74.7% of the patients. Echocardiographically determined left atrium diameter was similar in the two groups. Conversion to sinus rhythm occurred in 24 of 41 patients allocated to propafenone and in 10 of 34 patients allocated to placebo (odds ratio 3.2, 95% confidence intervals 1.3-7.9;p<0.01). Mean conversion time was 34 ± 29 and 71 ± 55 min, respectively, for propafenone and placebo. Mean heart rate in nonconverters decreased from 146 to 109 beats/min in patients treated with propafenone while it remained virtually unchanged in those treated with placebo. Only minor side effects were noted. Conclusions: Intravenous propafenone is an effective therapeutic option for restoring sinus rhythm in patients with paroxysmal AF of recent onset.     

环肺静脉口外线性消融治疗心房颤动术后房性心律失常的随访研究

目的通过随访探讨心房颤动(房颤)射频消融术后近期房性心律失常发作对远期成功率的影响,并探讨发生机制。方法2004年4月至2005年9月共入选52例房颤患者,男性44例,女性8例,年龄24～67(52．6±12．0)岁,病程2-280(35．8±37)个月。其中42例为阵发性房颤,10例为持续性房颤,所有患者均有房颤发作的心电图。13例合并原发性高血压,2例合并房间隔缺损,2例为峡部依赖型心房扑动消融术后,余均无器质性心脏病。所有患者在建立En- Site-NavX左心房几何构型后,于肺静脉口外0．5～1．0 cm处环左侧和右侧肺静脉设置消融线。盐水灌注消融导管于系统导航下沿拟定的消融线逐点消融至肺静脉电位消失。阵发性房颤患者均每日服用普罗帕酮450 mg,培哚普利4 mg,共3个月;持续性房颤患者服用胺碘酮第1周0．6 g／d,第2周O．4g/d,以后0．2g／d,共3个月;培哚普利4 mg／,d,共3个月。结果术后随访6～23 (15．0±5．1)个月。4例因并发症排除;余48例患者,1例术后1个月内发作非典型心房扑动,持续2 d后自行转复窦性心律,随访7个月未有房性心律失常发作。20例患者术后3个月内有阵发性房颤发作,3个月后,12例患者房颤不再发作,余8例随访至6个月,仍有房颤发作。结论心房颤动射频消融术后近期房颤发作者,并不能预测远期房性心律失常发作。术后3个月内有房性心律失常发作而以后不再发作者,可能是心房电学和组织学重构逆转的一个步骤。     

Mechanisms, prevention, and treatment of atrial fibrillation after cardiac surgery

Post-operative atrial fibrillation (POAF) is a frequent complication occurring in 30% to 50% of patients after cardiac surgery. It is associated with an increased risk of mortality and morbidity, predisposes patients to a higher risk of stroke, requires additional treatment, and increases the costs of the post-operative care. The aim of this review is to present the current state of knowledge about the risk factors, mechanisms, prevention, and treatment of this complication. In addition to the well known risk factors for the development of POAF such as age, left atrial enlargement, and valvular surgery, new metabolic risk factors related to visceral obesity have been identified. With regard to the prevention of POAF, beta-blocker drugs are effective and safe and can be used in most patients, whereas amiodarone can be added in high-risk patients. Biatrial pacing was shown to be effective; however, its complexity might limit its application. Although there are only few data regarding the usefulness of magnesium, statins, N-3 polyunsaturated fatty acids, and corticosteroids, their addition to beta-blocker drugs might be of benefit for further reducing POAF. Treatment includes the use of an AV nodal blocking agent to achieve the rate control. If AF does not spontaneously convert to sinus rhythm within 24 h, anticoagulation should be initiated and a rhythm control strategy should be attempted. More investigations are warranted to explore mechanisms by which POAF occurs. This new knowledge would undoubtedly translate into a more efficient prevention and treatment of this common post-operative complication that is associated with a major health and economic burden.     

The use of propafenone in the treatment of tachyarrhythmias in children

Propafenone was given to 60 children (mean age 4.5 years) withparoxysmal re-entrant supraventricular tachycardia (rSVT: 41cases), postoperative automatic junctional tachycardia (JET:eight cases), automatic atrial tachycardia (AT: four cases),ventricular tachycardia (VT: four cases) and atrial flutter(AF: three cases). In acute cases (29) propafenone was administered intravenously(mean dose 1.3±0.5 mg . kg^–1) chronic oral treatment(mean dose of either 11±3.3 mg . kg. day^–1 or 265±78mg . m^–2 . day^–1) was given to 48 children, in 2–3divided doses. Overall efficacy was 76% for acute and 69% forchronic treatment, with best results in paroxysmal rSVT. Itwas effective in 89% acutely of those treated acutely and in69% of those administered chronically. The efficacy of propafenonein the prevention of rSVT was strictly related to the incidenceof attacks before treatment. propafenone was indeed inefficaciousin 6/11, 6/14 and 0/12 of patients with daily, weekly and monthlyattacks respectively. Side effects were observed in 25% of patients: 6% required suspensionof therapy due to pro-arrhythrnic effects in one patient onintravenous administration, peripheral neuropathy in one caseand hypotension in two postoperative JET patients. In conclusion, its efficacy and limited side effects make propafenonea relatively safe and very useful drug in the treatment of varioustachyarrhythmias. However, risk of unpredictable toxic levelsrequires careful use of the drug especially in the first daysof treatment, when a daily monitoring of ECG is strongly recommended.     

Randomized controlled trial of bilateral intrapleural block in cardiac surgery

The aim of this study was to determine the efficacy of bilateral intrapleural block with bupivacaine as a preemptive analgesic for postoperative pain in coronary artery bypass graft surgery. In a double-blind prospective clinical trial, 70 patients were randomly divided into a bupivacaine group (20 mL bupivacaine 0.25% and 0.5 mL adrenaline 1/200,000 each side) and a control group (20.5 mL normal saline each side). Evaluation of the severity of pain was performed using the visual analog scale at 12 and 24 h after entering the intensive care unit and again during chest tube removal. Pain scores at 12 and 24 h after intensive care unit admission were significantly lower in the bupivacaine group. There were no side-effects related to intrapleural block, such as pneumothorax or emphysema. In coronary artery bypass graft candidates, preemptive analgesia with bilateral intrapleural block using bupivacaine provided relatively less painful conditions during the first 24 h after surgery, but it did not improve the clinical outcome.     

Effectiveness of intravenous propafenone for conversion of recent-onset atrial fibrillation: A placebo-controlled study

To evaluate the efficacy of propafenone in converting recent-onset atrial fibrillation (AF) lasting <7 days, 182 patients were treated intravenously with propafenone (Group 1, n = 98) and with placebo 0.9% saline solution (Group 2, n = 84) in a double blind study. The treatment was continued until sinus rhythm (SR) was restored, but for no more than 24 h. Eighty-nine patients treated with propafenone (90.8%) and 27 patients treated with placebo (32.1%) responded to the treatment and SR was restored (p < 0.0005). The mean time for SR restoration was 2.51± 2.77 h in Group 1, and 17.15± 7.8 h in Group 2 (p < 0.0005). In both groups the patients in whom SR was not restored (nonresponders) had larger left atrial size and longer duration of AF than responders at the onset of the arrhythmia. Nonresponders in Group 1 showed a decrease in mean ventricular rate (MVR) from 143± 16 to 101± 18 (p < 0.0005), while in the nonresponders in Group 2 no reduction of MVR was observed. Two patients whose SR was restored with propafenone had sinus standstill lasting 3.4 and 3.8 s, respectively. Propafenone used intravenously is an effective, quick, and safe drug for treating AF. Moreover, it significantly reduces MVR in nonresponders.     

Naproxen as prophylaxis against atrial fibrillation after cardiac surgery: the NAFARM randomized trial

Purpose

We sought to assess the effect of naproxen versus placebo on prevention of atrial fibrillation after coronary artery bypass graft (CABG) surgery.

Methods

In this randomized, double-blind, placebo-controlled, single-center trial of 161 consecutive patients undergoing CABG surgery, patients received naproxen 275 mg every 12 hours or placebo at the same dosage and interval over 120 hours immediately after CABG surgery. The primary outcome was the occurrence of atrial fibrillation in the first 5 postoperative days.

Results

The incidence of postoperative atrial fibrillation was 15.2% (12/79) in the placebo versus 7.3% (6/82) in the naproxen group (P = .11). The duration of atrial fibrillation episodes was significantly lower in the naproxen (0.35 hours) versus placebo group (3.74 hours; P = .04). There was no difference in the overall days of hospitalization between placebo (17.23 ± 7.39) and naproxen (18.33 ± 9.59) groups (P = .44). Intensive care unit length of stay was 4.0 ± 4.57 days in the placebo and 3.23 ± 1.25 days in the naproxen group (P = .16). The trial was stopped by the data monitoring committee before reaching the initial target number of 200 patients because of an increase in renal failure in the naproxen group (7.3% vs 1.3%; P = .06).

Conclusions

Postoperative use of naproxen did not reduce the incidence of atrial fibrillation but decreased its duration, in a limited sample of patients after CABG surgery. There was a significant increase in acute renal failure in patients receiving naproxen 275 mg twice daily. Our study does not support the routine use of naproxen after CABG surgery for the prevention of atrial fibrillation.     

Randomized, double-blind, placebo-controlled trial of corticosteroids after Kasai portoenterostomy for biliary atresia

The objective of this study was to evaluate adjuvant corticosteroids after Kasai portoenterostomy for biliary atresia. The study consisted of a prospective, 2-center, double-blind, randomized, placebo-controlled trial of post-Kasai portoenterostomy corticosteroids (oral prednisolone: 2 mg/kg/day from day 7 to day 21 and 1 mg/kg/day from day 22 to day 28). The data were compared with chi2 or Mann-Whitney tests, as appropriate. Seventy-one postoperative infants with type 3 biliary atresia were randomized to receive either oral prednisolone (n = 36) or a placebo (n = 37). At 1 month, the median bilirubin level was lower in the steroid group (66 versus 92 micromol/L, P = 0.06), but no difference was evident at 6 (P = 0.56) or 12 (P = 0.3) months. The proportion of infants with a normal bilirubin level (<20 micromol/L) at 6 (47% versus 49%, P = 0.89) and 12 months (50% versus 40%, P = 0.35) was not significantly different. The need for transplantation by 6 (12% versus 13%, P = 0.99) and 12 months (26% versus 35%, P = 0.47) was not significantly different. The steroid effect was more pronounced in younger infants (less than 70 days at Kasai portoenterostomy, n = 51), with a reduced bilirubin level at 1 month (64 versus 117 micromol/L, P = 0.01) and with a greater proportion with a normal bilirubin level at 12 months (54% versus 37%, P = 0.22). CONCLUSION: There was a beneficial effect on the rate of reduction of bilirubin in the early postoperative period (specifically in infants less than 70 days old at surgery), but this steroid regimen did not reduce the need for liver transplantation.     

Risk factors for atrial tachyarrhythmias after the fontan operation

Objectives. The purpose of this study was to define the incidence and risk factors for atrial tachyarrhythmias after the Fontan operation.Background. Atrial tachyarrhythmias cause morbidity after the Fontan operation. Causative factors may be affected by the type of systemic to pulmonary connection.Methods. The Fontan operation was performed in 270 consecutive patients between 1982 and 1992. The mean age at operation was 7.0 ± 4.3 years. Direct atriopulmonary connection was used in 138 patients (51%), total cavopulmonary connection in 94 (35%) and right atrial to right ventricular connection in 38 (14%).Results. Atrial tachyarrhythmias were seen early postoperatively in 55 patients (20%), preoperative atrial tachyarrhythmia being the only risk factor. Follow-up was achieved for 228 early survivors (97%) at a mean interval of 4.4 years. There were 20 late deaths. Late atrial tachyarrhythmias were noted in 29% of patients who received an atriopulmonary connection, 14% of those who received a total cavopulmonary connection and 18% of those who received a right ventricular connection (p < 0.02).Significant risk factors as determined by unvariate and multiple logistic regression analysis were atriopulmonary connection type (odds ratio 0.40 for total cavopulmonary relative to atriopulmonary connection [p < 0.05] and 0.37 for right ventricular relative to atriopulmonary connection [p = 0.08]), longer follow-up interval (odds ratio 1.32 for each consecutive year [p < 0.002]) and atrial tachyarrhythmia in the operative period (odds ratio 6.31 [p < 0.0001]).Conclusions. Early postoperative atrial tachyarrhythmias, length of follow-up and atriopulmonary connection are significant independent risk factors for the presence of late atrial tachyarrhythmias.     

Quantitative electrocardiography for predicting postoperative atrial fibrillation after cardiac surgery

Background

Atrial fibrillation (AF) after cardiac surgery is a common marker of poor outcomes. Quantitative electrocardiographic (ECG) measurements may be valuable predictors of postoperative AF.

Methods

We evaluated clinical and ECG predictors of postoperative AF in 13 356 patients who underwent cardiac surgery in sinus rhythm.

Results

A total of 4724 patients (35%) developed postoperative AF. P-wave amplitude in leads aVR and V₁ were the strongest ECG predictors. A less negative P-wave amplitude in lead aVR was associated with increased risk for postoperative AF (odds ratio, 1.46; 95% confidence interval, 1.32-1.61), as was a more positive or a more negative P-wave amplitude in lead V₁ (odds ratio, 1.25; 95% confidence interval, 1.16-1.36) after adjusting for clinical and procedural predictors of postoperative AF. Reclassification analysis showed a 7% discrimination improvement (P < .0001).

Conclusions

P-wave amplitude in lead aVR and lead V₁ are powerful predictors of postoperative AF and, in combination with other clinical predictors, can guide application of prophylactic interventions.     

围术期应用胺碘酮预防治疗心脏术后心房颤动

目的评价心脏手术围术期预防性应用胺碘酮对术后心房颤动(简称房颤)的预防作用。方法采用双盲、随机研究,将124例心脏手术者随机分为胺碘酮组(n=64),对照组(n=60)。胺碘酮组术前每天服用胺碘酮200mg,3次/天,至少7天,术后改为每天口服200mg,1次/天,直到出院。对照组则服用安慰剂,其剂量及服药方法与胺碘酮组相同。术前服用时间为13±7天,总剂量为4.8±0.9g。结果胺碘酮组术后房颤发生率、房颤时的心室率均较对照组低(23.4%vs41.7%,112±21次/分vs135±31次/分,P均<0.05),两组围术期并发症的发生率及死亡率均无显著差异。胺碘酮组的住院时间较对照组短(14.9±3.3天vs20.5±2.6天,P<0.05)。结论心脏手术围术期预防性服用胺碘酮是安全的,并且能显著降低术后房颤的发生率及房颤发生时的心室率,缩短住院时间。