Atrial fibrillation following cardiac surgery: clinical features and preventative strategies

Atrial fibrillation (AF) is a common complication of cardiacsurgery, with an increasing incidence. Post-operative AF resultsin many complications and increased healthcare resources. Despitesubstantial interest in the prediction and prevention of post-operativeAF, as well as guidelines for the management of this commonarrhythmia, there is still some uncertainty about appropriaterisk stratification and management. The aim of this review articleis to provide an overview of clinical predictive features forthe development of AF following cardiac surgery and suitablepreventive measures, using both antiarrhythmic and non-antiarrhythmicstrategies.     

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。     

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.     

心脏外科术前使用他汀类药物预防术后心房颤动发生的荟萃分析

目的 从循证医学的角度评价在拟行心脏手术的患者中,他汀类药物术前干预对心脏外科手术后心房颤动(房颤)发生的影响.方法 计算机检索和筛选他汀类药物术前应用对心脏外科手术后房颤发生影响的随机对照试验(randomized controlled trial,RCT),根据确定的纳入标准和排除标准提取文献资料并作质量评价,采用Cochrane协作网提供的Review Manager 5.1软件进行荟萃(meta)分析.结果 共纳入11个RCT研究,共1542例患者.使用随机效应模型合并,在常规治疗的基础上,他汀类药物手术前应用比对照组(未使用他汀类药物或使用安慰剂)明显降低心脏外科手术后房颤发生率[OR=0.48,95％ CI为(0.38,0.61)],P＜0.00001；缩短重症监护住院时间[加权均数差(weighted mean difference,WMD)为-0.08,95％ CI为(-0.13,-0.03)],P=0.003,单位:d.缩短总住院时间[WMD=-0.49,95％ CI为(-0.72,-0.27)],P＜0.0001,单位:d.结论 他汀类药物手术前应用,明显降低心脏外科手术后房颤发生率,缩短在重症监护中心和总住院时间.但由于纳入的研究数量偏少,且存在着一定偏倚风险,因此该疗效评价的结果尚需高质量大样本的随机双盲对照试验的验证.     

Interventions for prevention of post-operative atrial fibrillation and its complications after cardiac surgery: a meta-analysis.

AIMS: Atrial fibrillation (AF) is the most common complication after cardiac surgery. We aimed to evaluate, by meta-analysis, all randomized trials testing interventions for preventing AF. METHODS AND RESULTS: Ninety-four trials of prevention of post-operative AF were identified, by standard search methods, and analysed by standard meta-analysis techniques. All five commonly tested interventions, beta-blockers (BBs), sotalol, amiodarone, magnesium, and atrial pacing, were effective in preventing AF. The odds ratio (OR) for the effect of BB on the incidence of AF was 0.36 (95% CI 0.28-0.47, P<0.001), but after trials confounded by post-operative non-study BB withdrawal were excluded was 0.69 (95% CI 0.54-0.87, P=0.002). Sotalol reduced AF, compared with placebo (OR 0.34, 95% CI 0.26-0.45, P<0.001) and compared with conventional BB (OR 0.42, 95% CI 0.26-0.65, P<0.001). Amiodarone reduced AF (OR 0.48, 95% CI 0.40-0.57, P<0.001). Magnesium (Mg) also had an effect (OR 0.57 95% CI 0.42-0.77) but there was significant heterogeneity (P<0.001), partly explained by concomitant BB. The effect of Mg with BB was less (OR 0.83, 95% CI 0.60-1.16). Pacing reduced AF (OR 0.60, 95% CI 0.47-0.77, P<0.001), despite wide variations in techniques. Only amiodarone and pacing significantly reduced length of stay, average -0.60 days (95% CI -0.92 to -0.29) and -1.3 days (95% CI -2.55 to -0.08), respectively. Collectively, all treatments analysed together reduced stroke (OR 0.63, 95% CI 0.41-0.98). Amiodarone was the only intervention that alone significantly reduced stroke rate (OR 0.54, 95% CI 0.30-0.95). CONCLUSION: All five interventions reduced the incidence of AF, though the effect of BBs is less than previously thought. The significant reductions in length of stay and stroke in meta-analysis suggest that there are worthwhile benefits from aggressive prevention. Larger studies to confirm these clinical benefits and evaluate their cost-effectiveness would be worthwhile.     

Atrial fibrillation: Mechanistic insights and treatment options

Atrial fibrillation (AF) remains the most common clinically encountered arrhythmia. Unlike supraventricular arrhythmias that use a defined mechanism, AF involves a wide spectrum of arrhythmias from lone AF to paroxysmal to chronic AF. AF is an arrhythmia that may develop in several ways. Mechanical remodeling manifests as decreased atrial contractility and increased atrial compliance which leads to a stretch of the atrial myocardium. Atrial remodeling may also increase in atrial fibrosis which can slow conduction velocity and can shorten the refractory period in atria with long-standing AF. It is still unclear whether initiation of AF activates direct inflammatory effects or whether the presence of a pre-existing systemic inflammatory state promotes further persistence of AF.Currently, the patient population undergoing AF ablation has greatly expanded. Patients are older and have larger left atrial size and are more likely to have persistent/permanent AF. It is likely that AF comprises a spectrum of disease with no single mechanism adequate enough to comprehensively explain AF and its variability. The management of patients with AF involves elements of anticoagulation, rate control and rhythm control and such treatment strategies are not necessarily mutually exclusive of each other.     

Atrial fibrillation independently prolongs hospital stay after coronary artery bypass surgery

BACKGROUND: Atrial fibrillation (AF) is the most common arrhythmia occurring in patients after coronary artery bypass surgery (CABG). HYPOTHESIS: The purpose of this study was to determine whether AF independently prolonged postoperative length of stay (LOS). METHODS: Consecutive patients undergoing elective CABG were identified. Baseline clinical variables, postoperative course including the development of AF, and postoperative LOS were recorded. RESULTS: In all, 216 patients (aged 61 +/- 13 years) were examined. Postoperative LOS was 11.3 +/- 6.4 days (median LOS = 9 days). Fifty-five patients (25%) developed AF. Among 16 variables examined, the univariate predictors of LOS included age (p < 0.001), preoperative left ventricular ejection fraction (p < 0.001), absence of a prior smoking history (p < 0.05), bypass limited to venous conduits (p < 0.001), postoperative AF (p < 0.001), and the occurrence of a postoperative event (p < 0.001). Length of stay for patients who developed AF was significantly longer than that for patients who did not (15.1 +/- 9.0 vs. 10.0 +/- 4.6 days, p < 0.001). After adjusting for other significant variables, the occurrence of AF after CABG independently prolonged LOS: patients who developed AF stayed 3.2 +/- 1.7 days longer than patients who did not (p < 0.001). CONCLUSIONS: Atrial fibrillation lengthens hospital stay after CABG, and its effect is independent of other important variables. Identification of patients who are at risk for AF and successful treatment to prevent AF will likely contribute to major reductions in consumption of health care resources in patients with CABG.     

Diastolic function and new-onset atrial fibrillation following cardiac surgery

Background:

Numerous studies have reported predictors of new-onset postoperative atrial fibrillation (POAF) following cardiac surgery, which is associated with increased length of stay, cost of care, morbidity, and mortality. The purpose of this study was to examine the association between preoperative diastolic function and occurrence of new-onset POAF in patients undergoing a variety of cardiac surgeries at a single institution.

Methods:

Using data from a prospective study from November 2007 to January 2010, a retrospective review was conducted. The diastolic function of each patient was determined from preoperative transthoracic echocardiograms. Occurrence of new-onset POAF was prospectively noted for each patient in the original study. Demographic and operative characteristics of the study population were analyzed to determine predictors of POAF.

Results:

Of 223 patients, 91 (40.8%) experienced new-onset POAF. Univariate predictors of POAF included increasing age, male gender, operations involving mitral valve repair/replacement, nonsmoking, hypertension, increased intraoperative pulmonary artery pressure, grade I diastolic dysfunction, abnormal diastolic function of any grade, decreased medial e’, elevated medial E/e’, and increased left atrial volume. Multivariate predictors of POAF included increasing age, increased left atrial volume, and elevated initial intraoperative pulmonary artery pressure. Even after exclusion of patients with hypertrophic obstructive cardiomyopathy or those undergoing mitral valve operations, diastolic dysfunction was not a multivariate predictor of POAF.

Conclusions:

In the patient population studied here, preoperative diastolic dysfunction was not predictive of POAF. In addition to increasing age, initial intraoperative pulmonary artery systolic pressure and left atrial volume were both significant multivariate predictors of POAF.     

Polyunsaturated fatty acids for the prevention of atrial fibrillation after cardiac surgery: An updated meta-analysis of randomized controlled trials

BackgroundSeveral clinical trials showed inconsistent results of the effect of polyunsaturated fatty acids (PUFA) on the incidence of post-operative atrial fibrillation (POAF). The aim of this meta-analysis is to investigate the effect of PUFA on the incidence of POAF in patients undergoing cardiac surgery.Methods and resultsPUBMED, EMBASE, Cochrane Library, and Google Scholar databases were searched for randomized controlled trials. Statistical heterogeneity was assessed using I² statistic and Cochran's Q statistic. The effect of PUFA on the incidence of POAF was presented as risk ratio (RR) with 95% confidence intervals (CIs) using a fixed effect model or random effect model depending on statistical heterogeneity. Subgroup analyses were conducted based on the baseline characteristics of patients, types of surgery, the ratio of eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA), and the quality of the studies. Eight trials with 2687 patients were included in the analysis. Treatment with PUFA had no effect on the incidence of POAF in patients undergoing cardiac surgery compared to placebo [RR 0.86; 95% CI 0.71–1.04, p = 0.110]. Subgroup analyses showed the quality of the studies, the ratio of EPA/DHA, accompanied with diabetes might impact the effect of PUFA on POAF. No evidence of publication bias was detected.ConclusionsThe present analysis suggests that treatment with PUFA preoperatively has no effect on the incidence of POAF in patients undergoing open heart surgery. However, patients with diabetes might get benefits from the treatment with PUFA preoperatively.     

Atrial natriuretic peptide in atrial fibrillation before and after electrical cardioversion therapy

In eight patients with atrial fibrillation of less than 3 monthsduration and without congestive heart failure the plasma concentrationof atrial natriuretic peptide was determined one day before,the day after and again 30 days after electrical cardioversiontherapy. The pretreatment plasma concentration of the peptidewas 99 pg mg^–1 (23–480, median and range). The dayafter cardioversion to sinus rhythm the peptide concentrationhad normalized to 36 pg ml^–1 (18–151). The plasmaconcentration of atrial natriuretic peptide remained stablein all but one patient for a period of 30 days (46 pg ml^–1,16–695) (P = 0·03). In conclusion, the plasma concentration of atrial natriureticpeptide in patients with atrial fibrillation was significantlyreduced after electrical cardioversion to sinus rhythm and remainedstable for a period of 30 days.     

Renal function is associated with risk of atrial fibrillation after cardiac surgery

BACKGROUND: Atrial fibrillation (AF) frequently occurs after cardiac surgery and is responsible for increased morbidity and resource use. The aim of the present study was to evaluate the association of impaired renal function and the development of postoperative AF. METHODS AND RESULTS: Patients undergoing elective cardiac surgery in the absence of significant left ventricular dysfunction (n=253; average age 65+/-11 years) were recruited to the present prospective study. Ninety-nine patients (39.1%) developed AF during the postoperative period. Creatinine clearance, estimated by the calculated glomerular filtration rate (GFR), was prospectively assessed to determine the association of baseline renal function and the development of postoperative AF. Baseline calculated GFR was assessed as a continuous and a categorical variable (normal: greater than 90 mL/min/1.73 m(2); mildly decreased: 60 mL/min/1.73 m(2) to 89 mL/min/1.73 m(2); and moderately to severely decreased: less than 60 mL/min/1.73 m(2)). Baseline creatinine clearance was 72+/-22.2 mL/min/1.73 m(2) and 78.8+/-23.5 mL/min/1.73 m(2) in patients with and without postoperative AF, respectively (P=0.02). There was an independent association between decreasing calculated GFR and the development of postoperative AF (OR for 10 mL decrease in calculated GFR: 1.21, 95% CI 1.02 to 1.39). In addition to calculated GFR, surgery for valvular heart disease (versus coronary artery bypass grafting [OR 2.23, 95% CI 1.09 to 3.14; P<0.01]), age (OR per 10-year increase in age 1.92, 1.18 to 2.59) and perioperative nonuse of beta-adrenergic blockers (OR 1.62, 95% CI 1.12 to 3.55; P<0.01) were identified as independent predictors of postoperative AF. CONCLUSIONS: In the setting of cardiac surgery, impaired calculated GFR is associated with an increased risk for the development of postoperative AF. These data provide additional evidence supporting the association between renal dysfunction and adverse cardiovascular outcomes.     

Atrial fibrillation and subtype of atrial fibrillation in cardiac amyloidosis: clinical and echocardiographic features,impact on mortality

Background: Atrial fibrillation (AF) commonly affects patients with cardiac amyloidosis (CA). Amyloid deposition within the left atrium may be responsible for the subtype of AF in either permanent or non-permanent form. The prognostic implications of AF and its clinical subtype according to the type of CA are still controversial in this population. This study sought to investigate the prevalence, incidence and prognostic implications of AF and the clinical subtype of AF (permanent or non-permanent) in patients with CA.

Methods: Two hundred and thirty-eight patients with CA and full medical records were retrospectively enrolled in the study: About 115 (48%) with light chain (AL) amyloidosis and 123 (52%) with transthyretin amyloidosis (ATTR). Patient’s medical records were reviewed to establish baseline prevalence, incidence and impact on all-cause and cardiovascular mortality during follow-up of AF.

Results: One hundred and four (44%) patients had history of AF at the time of diagnosis: 62 (60%) permanent and 42 (40%) non-permanent. There were 30 (26%) and 74 (60%) patients with history of AF among patients with AL and ATTR (including 5 hereditary and 69 wild-type), respectively (p<.0001). During the follow-up, 48 new patients developed AF (29, 12 and 7 among patients with AL, wild-type ATTR and hereditary ATTR). After adjustment for age, survival was similar in patients with or without history of AF (HR 0.87 (95% CI, 0.60 to 1.27; p?=?.467). AF had no impact on cardiovascular mortality. Among the 152 patients with history of AF included in the whole study, there were 75 (49%) patients with permanent AF. After adjustment for age, survival was similar in patients with permanent and non-permanent AF: HR 1.29 (95% CI, 0.84 to 1.99; p?=?.251). The results were the same among patients with AL or wild-type amyloidosis. Subtype of AF had no impact on cardiovascular mortality.

Conclusions: AF is common in patients with CA. However, AF and clinical subtype of AF have no impact on all-cause mortality, whatever the type of amyloidosis.     

Atrial fibrillation after surgery for esophageal carcinoma： Clinical and prognostic significance

AIM:To retrospectively evaluate the clinical relevance,perioperative risk factors,outcome of differentpharmacological prophylaxis,and short-term prognosticvalue of atrial fibrillation(AF)after surgery foresophageal carcinoma.METHODS:We retrospectively studied 63 patients withAF after surgery for esophageal carcinoma in comparisonwith 126 patients without AF after esophagectomyduring the same time.Postoperative AF incidence wasrelated to different clinical factors possibly involved in itsoccurrence and short-term survival.RESULTS:A strong relationship was observed betweenAF and postoperative hypoxia,history of chronicobstructive pulmonary disease(COPD),postoperativethoracic-gastric dilatation,age older than 65 years,malesex and history of cardiac disease.No difference wasobserved between the two groups with regard to short-term mortality and length of hospital stay.CONCLUSIONS:AF occurs more frequently afteresophagectomy in aged and male patients.Other factorscontributing to postoperative AF are history of COPD andcardiac disease,postoperative hypoxia and thoracic-gastric dilatation.     

Galectin-3 is an independent predictor of postoperative atrial fibrillation and survival after elective cardiac surgery

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A comparison of clinical characteristics and long-term prognosis in asymptomatic and symptomatic patients with first-diagnosed atrial fibrillation: The Belgrade Atrial Fibrillation Study

Background

To investigate baseline characteristics and long-term prognosis of carefully characterized asymptomatic and symptomatic patients with atrial fibrillation (AF) in a ‘real-world’ cohort of first-diagnosed non-valvular AF over a 10-year follow-up period.

Methods and results

We conducted an observational, non-interventional, and single-centre registry-based study of consecutive first-diagnosed AF patients. Of 1100 patients (mean age 52.7 ± 12.2 years and mean follow-up 9.9 ± 6.1 years), 146 (13.3%) had asymptomatic AF.Persistent or permanent AF, slower ventricular rate during AF (< 100/min), CHA₂DS₂–VASc score of 0, history of diabetes mellitus and male gender were independent baseline risk factors for asymptomatic AF presentation (all p < 0.01) with a good predictive ability of the multivariable model (c-statistic 0.86, p < 0.001).Kaplan–Meier 10-year estimates of survival free of progression of AF (log-rank test = 33.4, p < 0.001) and ischemic stroke (log-rank test = 6.2, p = 0.013) were significantly worse for patients with asymptomatic AF compared to those with symptomatic arrhythmia. In the multivariable Cox regression analysis, intermittent asymptomatic AF was significantly associated with progression to permanent AF (Hazard Ratio 1.6; 95% CI, 1.1–2.2; p = 0.009).

Conclusions

In a ‘real-world’ setting, patients with asymptomatic presentation of their first-diagnosed AF could have different risk profile and long-term outcomes compared to those with symptomatic AF. Whether more intensive monitoring and comprehensive AF management including AF ablation at early stage following the incident episode of AF and increased quality of oral anticoagulation could alter the long-term prognosis of these patients requires further investigation.