Residual atrial fibrillation and clinical consequences following postoperative supraventricular arrhythmias

Postoperative Atrial Fibrillation After Cardiac Surgery: A Meta-Analysis

BACKGROUND

Postoperative atrial fibrillation (POAF) is common after cardiac surgery and linked to poorer short-term and long-term outcomes; however, conflicting evidence exists on stroke risk and how the index procedure affects outcomes. This study aims to provide a comprehensive review of the published outcomes of POAF after cardiac surgery, examined as a whole and by index procedure.

METHODS

A systematic review of POAF after cardiac surgery was conducted. Outcomes related to POAF were analyzed in a meta-analysis, and aggregate survival data were derived to examine long-term survival.

RESULTS

Sixty-one studies with 239,018 patients were identified, the majority (78.7%) undergoing coronary surgery. POAF occurred in 25.5% of patients and was associated with significantly higher rates of early mortality and stroke (odds ratio [OR], 1.74; P < .001; and OR, 2.21, P < .001, respectively) along with longer intensive care and overall hospital length of stay (mean difference 0.8 days, P = .008; and mean difference 2.8 days, P < .001, respectively). After a median of 6.6 years (range, 0.5-20 years), mortality and stroke remained significantly higher for those with POAF (OR, 1.57, P < .001; and OR, 1.81, P = .001). Pooled hazard ratio for long-term mortality was significantly higher for patients who underwent coronary surgery compared with isolated valve surgery.

CONCLUSIONS

POAF is common after cardiac surgery and is associated with significantly higher rates of both short-term and long-term stroke and mortality as well as increased hospital stay. Differences in hazard for long-term survival may be due to the underlying pathophysiological risk factors for POAF, which differ by surgical procedure.

New-onset atrial fibrillation and outcomes following isolated coronary artery bypass surgery: A systematic review and meta-analysis

Prior meta‐analyses have shown that new‐onset atrial fibrillation (NOAF) occurs in up to 40% of patients following cardiac surgery and is associated with substantial major adverse cardiovascular events. The stroke and mortality implications of NOAF in isolated CABG without concomitant valve surgery is not known. We thought that NOAF would be associated with increased risk of stroke and mortality, even in patients undergoing isolated CABG. A blinded review of studies from MEDLINE, CENTRAL, and Web of Science was done by two independent investigators. Stroke, 30‐day/hospital mortality, long‐term cardiovascular mortality, and long‐term (>1 year) all‐cause mortality were analyzed. We used Review Manager Version 5.3 to perform pooled analysis of outcomes. Of 4461 studies identified, 19 studies (n = 129 628) met inclusion criteria. NOAF incidence ranged from 15% to 36%. NOAF was associated with increased risk of stroke (unadjusted OR 2.15 [1.82, 2.53] [P < .00001]; adjusted OR 1.88 [1.02, 3.46] [P = .04]). NOAF was associated with increased 30‐day/hospital mortality (OR 2.35 [1.67, 3.32] [P < .00001]) and long‐term cardiovascular mortality (OR 2.04 [1.35, 3.09] [P = .0007]) NOAF was associated with increased long‐term all‐cause mortality (unadjusted OR 1.79 [1.63, 1.96] [P < .00001]; adjusted OR 1.58 [1.24, 2.00] [P = .0002]). We found that the incidence of NOAF following isolated CABG is high and is associated with increased stroke rate and mortality. Early recognition and management of NOAF could improve outcomes.

Patients who develop post-operative atrial fibrillation have reduced survival after off-pump coronary artery bypass grafting

Objective

Post-operative atrial fibrillation (POAF) increases hospital stay, resource utilization, morbidity, and mortality. However, there is paucity of data about its effect in Indian patients undergoing off-pump coronary artery bypass grafting (CABG).

Methods

Seven hundred forty-eight patients underwent off-pump CABG from January 2015 to December 2016 (24 months). One hundred twenty-seven patients (16.7%) developed POAF. In an effort to mitigate the effects of wider risk factors on perioperative outcomes, a separate sub-analysis of patients based on risks quantified by EuroSCORE II (<> 3) was also performed.

Results

Age > 60 years and development of sepsis were the independent predictors for the development of POAF. Thirty-day/mortality rate was higher in the POAF group (7.1% vs. 1.4%; p value < 0.001). POAF was associated with increased ICU and hospital stay and increased incidence of stroke and renal dysfunction. The survival was significantly lower in the POAF group compared with the normal sinus rhythm (NSR) (3-year survival in POAF was 81.3% vs. 94.4% in the NSR group; Hazard ratio (HR) 3.867 (1.989–7.516)). Intra-aortic balloon pump (IABP) usage, age ≥ 60 years and sepsis were independent predictors for the development of POAF in low-risk patients. For the NSR group, 1-year survival was 98% and 3-year survival was 95.7%. For the POAF group, 1-year survival was 94.4% and 3-year survival was 84.0% (HR. 3.794 (1.897–7.591)).

Conclusion

The incidence of POAF was lower than reported in the wider global literature. Increasing age and development of post-operative sepsis were strong independent predictors of POAF. POAF increases the morbidity; length of hospital stay and these patients show decreased survival after off-pump CABG.

Atrial Fibrillation Post Coronary Artery Graft Surgery: A Review Of Literature

Atrial fibrillation (AF) is a failure that is observed in heart disease and is also known to be the most common heart rhythm disturbance post coronary artery bypass surgery. Although AF is considered a transient problem, it is usually accompanied with a variety of complications and morbidity for patients and may result in death. In the present study, pre- and post-operative considerable factors which may increase the risk and mortality of AF, and possible treatments have been concisely reviewed.

New-Onset Atrial Fibrillation After Coronary Artery Bypass Graft and Long-Term Risk of Stroke: A Meta-Analysis

BACKGROUND

New-onset atrial fibrillation (NOAF) after coronary artery bypass graft is related to an increased short-term risk of stroke and mortality. We investigated whether the long-term risk of stroke is increased.

METHODS AND RESULTS

We performed a systematic review and meta-analysis of studies that included patients who had coronary artery bypass graft and who afterwards developed NOAF during their index admission; these patients did not have previous atrial fibrillation. The primary outcome was risk of stroke at 6 months or more in patients who developed NOAF compared with those who did not. Odds ratios, relative risk, and hazard ratios were considered equivalent; outcomes were pooled on the log-ratio scale using a random-effects model and reported as exponentiated effect-sizes. We included 16 studies, comprising 108 711 participants with a median follow-up period of 2.05 years. Average participant age was 66.8 years, with studies including an average of 74.8% males. There was an increased long-term risk of stroke in the presence of NOAF (unadjusted studies effect-sizes=1.36, 95% confidence interval, 1.12-1.65, P=0.001, adjusted studies effect-sizes=1.25, 95% confidence interval, 1.09-1.42, P=0.001). There was evidence of moderate effect variation because of heterogeneity in studies reporting unadjusted (P=0.021, I2=49.8%) and adjusted data (P=0.081, I2=49.1%), and publication bias in the latter group (Egger's test, P=0.031). Sensitivity analysis on unadjusted data by study quality, design, and surgery did not alter the effect direction.

CONCLUSIONS

Presence of NOAF in patients post-coronary artery bypass graft is associated with increased long-term risk of stroke compared with patients without NOAF. Further studies may show whether the increased risk is mediated by atrial fibrillation and whether anticoagulation reduces risk.

Postoperative atrial fibrillation: Target for stroke prevention?

Purpose

A substantial number of patients without a history of atrial fibrillation who undergo surgery develop one or more episodes of atrial fibrillation in the first few days after the operation. We studied whether postoperative transient atrial fibrillation is a risk factor for future atrial fibrillation, stroke and death.

Method

We performed a narrative review of the literature on epidemiology, mechanisms, risk of atrial fibrillation, stroke and death after postoperative atrial fibrillation. We reviewed antithrombotic guidelines on this topic and identified gaps in current management.

Findings

Patients with postoperative atrial fibrillation are at high risk of developing atrial fibrillation in the long term. Mortality is also increased. Most, but not all observational studies report a higher risk of stroke. The optimal antithrombotic regimen for patients with postoperative atrial fibrillation has not been defined. The role of lifestyle changes and of surgical occlusion of the left atrial appendage in preventing adverse outcomes after postoperative atrial fibrillation is not established.

Conclusion

Further studies are warranted to establish the optimal strategy to prevent adverse long-term outcomes after transient, postoperative atrial fibrillation.

Atrial fibrillation at mid-term after bioprosthetic aortic valve replacement – implications for anti-thrombotic therapy

BACKGROUND

Little is known about mid-term (3-month) postoperative atrial fibrillation (MT-POAF) in patients treated with bioprosthetic aortic valve replacement (BAVR). The aim of this study was to describe the natural history, identify the predictors and investigate the potential consequences in terms of anti-thrombotic therapy.

METHODS AND RESULTS

During a longitudinal, prospective study, 219 patients were treated with BAVR early (7 days) and at mid-term postoperatively (30 and 90 days). POAF was monitored and risk factors were identified on logistic regression analysis. History of previous AF (OR, 3.08; 95% CI: 1.35-6.98), early POAF (OR, 5.93; 95% CI: 2.96-11.8), and BMI (per 5 kg/m(2): OR, 1.46; 95% CI: 1.03-2.09), were independent predictors for MT-POAF whereas sex, age and Euroscore were not. Results were identical when restricted to the 176 patients free from preoperative AF. In this subgroup, 36 patients (20.4%) had MT-POAF; 33 out of 174 (18.7%) would have required anticoagulation (CHA2DS2VASc score ≥ 1). Conversely, patients with BMI <27.7 and sinus rhythm at early follow-up had a very low risk of MT-POAF (OR, 0.16; 95% CI: 0.06-0.42).

CONCLUSIONS

There was a higher than expected occurrence of MT-POAF in patients treated with BAVR, particularly in overweight patients with early POAF. This raises the question of implementing an anti-thrombotic therapy in these patients at higher risk of delayed atrial arrhythmia.

Transient post-operative atrial fibrillation predicts short and long term adverse events following CABG

OBJECTIVE

To assess the relationship between the development of transient post-operative atrial fibrillation (TPOAF) following coronary artery bypass graft (CABG) surgery and risk of long-term mortality.

BACKGROUND

Atrial fibrillation (AF) following CABG is common and associated with increased morbidity and mortality in the perioperative period. However the impact of TPOAF and its management on long-term morbidity and mortality in patients undergoing first time, isolated CABG surgery remains unclear.

METHODS

The Cleveland Clinic Cardiovascular Information Registry was used to identify 5,205 consecutive patients who underwent CABG between January 1993 and December 2005. Patients with TPOAF (n=1,490) were compared to those without post-operative AF (n=3,645) for the endpoints of death, myocardial infarction (MI), or stroke at 1 year.

RESULTS

Overall rates of 1-year mortality, MI and stroke were 3.7%, 0.8%, and 2.6%, respectively. Patients with TPOAF had an increased risk of death at 1 year as compared to patients without POAF (6.4% vs. 2.7%; P<0.001), but there was not an increased risk of stroke or MI. Multivariate analysis identified TPOAF as an independent predictor of death at 1 year (HR 1.89, 95% CI, 1.42-2.53; P<0.001). After propensity matching, patients who developed TPOAF experienced a significantly increased risk of death compared with those without TPOAF (HR 1.96, 95% CI, 1.34-2.86; P<0.001).

CONCLUSIONS

In patients undergoing first time, isolated CABG, the presence of TPOAF identifies a subgroup of patients at increased risk for all-cause mortality. Future prospective studies to determine potential beneficial interventions in this large population are warranted.

Interventions for preventing post-operative atrial fibrillation in patients undergoing heart surgery

BACKGROUND

Atrial fibrillation is a common post-operative complication of cardiac surgery and is associated with an increased risk of post-operative stroke, increased length of intensive care unit and hospital stays, healthcare costs and mortality. Numerous trials have evaluated various pharmacological and non-pharmacological prophylactic interventions for their efficacy in preventing post-operative atrial fibrillation. We conducted an update to a 2004 Cochrane systematic review and meta-analysis of the literature to gain a better understanding of the effectiveness of these interventions.

OBJECTIVES

The primary objective was to assess the effects of pharmacological and non-pharmacological interventions for preventing post-operative atrial fibrillation or supraventricular tachycardia after cardiac surgery. Secondary objectives were to determine the effects on post-operative stroke or cerebrovascular accident, mortality, cardiovascular mortality, length of hospital stay and cost of treatment during the hospital stay.

SEARCH METHODS

We searched the Cochrane Central Register of ControlLed Trials (CENTRAL) (Issue 8, 2011), MEDLINE (from 1946 to July 2011), EMBASE (from 1974 to July 2011) and CINAHL (from 1981 to July 2011).

SELECTION CRITERIA

We selected randomized controlled trials (RCTs) that included adult patients undergoing cardiac surgery who were allocated to pharmacological or non-pharmacological interventions for the prevention of post-operative atrial fibrillation or supraventricular tachycardia, except digoxin, potassium (K(+)), or steroids.

DATA COLLECTION AND ANALYSIS

Two review authors independently abstracted study data and assessed trial quality.

MAIN RESULTS

One hundred and eighteen studies with 138 treatment groups and 17,364 participants were included in this review. Fifty-seven of these studies were included in the original version of this review while 61 were added, including 27 on interventions that were not considered in the original version. Interventions included amiodarone, beta-blockers, sotalol, magnesium, atrial pacing and posterior pericardiotomy. Each of the studied interventions significantly reduced the rate of post-operative atrial fibrillation after cardiac surgery compared with a control. Beta-blockers (odds ratio (OR) 0.33; 95% confidence interval) CI 0.26 to 0.43; I(2) = 55%) and sotalol (OR 0.34; 95% CI 0.26 to 0.43; I(2) = 3%) appear to have similar efficacy while magnesium's efficacy (OR 0.55; 95% CI 0.41 to 0.73; I(2) = 51%) may be slightly less. Amiodarone (OR 0.43; 95% CI 0.34 to 0.54; I(2) = 63%), atrial pacing (OR 0.47; 95% CI 0.36 to 0.61; I(2) = 50%) and posterior pericardiotomy (OR 0.35; 95% CI 0.18 to 0.67; I(2) = 66%) were all found to be effective. Prophylactic intervention decreased the hospital length of stay by approximately two-thirds of a day and decreased the cost of hospital treatment by roughly $1250 US. Intervention was also found to reduce the odds of post-operative stroke, though this reduction did not reach statistical significance (OR 0.69; 95% CI 0.47 to 1.01; I(2) = 0%). No significant effect on all-cause or cardiovascular mortality was demonstrated.

AUTHORS' CONCLUSIONS

Prophylaxis to prevent atrial fibrillation after cardiac surgery with any of the studied pharmacological or non-pharmacological interventions may be favored because of its reduction in the rate of atrial fibrillation, decrease in the length of stay and cost of hospital treatment and a possible decrease in the rate of stroke. However, this review is limited by the quality of the available data and heterogeneity between the included studies. Selection of appropriate interventions may depend on the individual patient situation and should take into consideration adverse effects and the cost associated with each approach.

Perioperative serum troponin I levels are associated with higher risk for atrial fibrillation in patients undergoing coronary artery bypass graft surgery

Atrial fibrillation (AF) remains a frequent complication after coronary artery bypass graft surgery (CABG). We evaluate the association of AF occurrence and serum cardiac troponin I (cTnI) levels in the early postoperative period after CABG. Between April 2009 and January 2010, 95 consecutive patients with sinus rhythm who underwent CABG were evaluated. The patients were divided into two groups according to their postoperative rhythms: sinus rhythm group (SR) and AF group (AF). Demographic, clinical variables, and troponin I were evaluated at the pre- and postoperative times. There were no clinical or demographic differences between the two groups. The postoperative troponin I in the SR group was lower than that in the AF group (0.66 ± 1.62 vs. 2.07 ± 5.01 ng/ml; P = 0.029). Using the receiver operating characteristic curves was found as the best cut-off value to predict AF occurrence at the value of 0.901 ng/ml. Using this value of cTnI, a sensitivity of 60% and a specificity of 87% for AF onset prediction were observed. The cTnI serum levels at the postoperative period after CABG were higher in patients who subsequently developed AF. The cut-off value of 0.901 ng/ml is useful for prediction and preventive therapeutic actions.

Postoperative atrial fibrillation is associated with late mortality after coronary surgery, but not after valvular surgery

BACKGROUND

Numerous studies have attempted to determine the etiology and prophylactic measures concerning atrial fibrillation (AF) after cardiac surgery. However, limited data are available analyzing the association between postoperative AF and late mortality. We sought to determine if AF after cardiac surgery affects postoperative survival.

METHODS

All cardiac surgery patients (n = 9,495) undergoing cardiac surgery between January 1994 and December 2004 were studied. The study population comprised coronary artery bypass graft surgery (CABG [n = 7,621]), valvular surgeries (n = 995), and their combination (n = 879). Patients affected by postoperative AF were identified, and long-term survival was obtained from Swedish population registry and evaluated using Cox proportional hazards methods to adjust for baseline differences.

RESULTS

The overall AF incidence was 26.7%, subdivided into 22.9%, 39.8%, and 45.2% for CABG, valve surgery, and combined procedures, respectively. The median follow-up for the entire study population was 7.9 years (maximum, 13.4). Postoperative AF independently affected long-term survival in CABG patients (hazard ratio 1.22; 95% confidence interval: 1.08 to 1.37). For isolated valvular surgery or combined procedures, AF was not significantly associated with long-term survival (hazard ratio 1.21, 95% confidence interval: 0.92 to 1.58; and hazard ratio 1.15, 95% confidence interval: 0.90 to 1.46, respectively).

CONCLUSIONS

Postoperative AF increases late mortality after isolated CABG surgery only. This finding was not statistically confirmed after isolated or combined valvular procedures. Our results draw the attention to possible AF recurrence after hospital discharge, indicating a strict postoperative surveillance.

Supraventricular Dysrhythmias

Cardiovascular nursing practice includes accountability for the clinical and organizational processes to ensure positive outcomes for patients having cardiac dysrhythmias. For patients with supraventricular dysrhythmias, nurses have studied patient outcomes related to mortality, morbidity, quality of life, psychological and physical functioning, and symptoms. Nurses have also explored these same outcomes associated with the management of supraventricular dysrhythmias. In addition, nurses have contributed to understanding organizational outcomes such as healthcare utilization and costs associated with these patients. For patients with atrial fibrillation after cardiac surgery, nurses have studied patient and organizational outcomes related to mortality, morbidity, symptoms, psychological and physical functioning, and economic outcomes. This research has included numerous interdisciplinary studies, and most of it has been descriptive or observational in design. Areas for future nursing outcomes research, including more interventional studies, are discussed.

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).

Epidemiology, Mechanisms, and Risks

Atrial fibrillation (AF) is one of the most frequent complications of cardiac surgery, affecting more than one third of patients. The mechanism of this arrhythmia is believed to be reentry. The electrophysiologic substrate may be preexisting or may develop due to heterogeneity of refractoriness after surgery. Multiple perioperative factors have been proposed to contribute to the latter, including operative trauma, inflammation, elevations in atrial pressure (including that due to left ventricular diastolic dysfunction), autonomic nervous system imbalance, metabolic and electrolyte imbalances, or myocardial ischemic damage incurred during the operation. Whether ectopic beats originating in the pulmonary veins explain at least some episodes of postoperative AF, as has been shown for nonsurgical patients with the arrhythmia, is of current interest as such sites could easily be isolated at the time of surgery. The development of postoperative AF is associated with a higher risk of operative morbidity, prolonged hospitalization, and increased hospital cost compared with that in patients remaining in sinus rhythm. Many factors have been identified as being associated with postoperative AF, but the most consistent variable across studies is increasing patient age. It is speculated that age-related pathologic changes in the atrium contribute to arrhythmia susceptibility. An important modifiable risk factor for postoperative AF is the failure to resume therapy with beta-adrenergic receptor blockers after surgery. The stratification of patients who are at higher risk for AF would focus preventative strategies on patients who are most likely to benefit from such therapy. Nonetheless, since postoperative AF often develops in patients with comorbidities who are predisposed to other complications and prolonged hospitalization, it is presently unclear whether the prevention of postoperative AF will result in improved patient outcomes, particularly shorter hospitalizations.

Interventions for preventing post-operative atrial fibrillation in patients undergoing heart surgery

BACKGROUND

Post-operative atrial fibrillation is a common complication of cardiac surgery and has been associated with increased incidence of other complications including post-operative stroke, increased hospital length of stay and increased cost of hospitalisation. Prevention of atrial fibrillation is a reasonable clinical goal and, consequently, many randomised trials have evaluated the effectiveness of pharmacological and non-pharmacological interventions. We systematically reviewed the literature and prepared meta-analyses to better understand the role and effects of various prophylactic therapies against post-operative atrial fibrillation.

OBJECTIVES

To assess the effects of pharmacological and non-pharmacological interventions for preventing post-cardiac surgery atrial fibrillation.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE and CINAHL from earliest achievable date to June 2003. We hand searched references from reports and earlier reviews. We searched abstract books and CD-ROMs from annual scientific meetings of American College of Cardiology, American Heart Association, North American Society of Pacing and Electrophysiology and European Heart Organization between 1997-2003. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials comparing pharmacological interventions or non-pharmacological interventions with control treatment, placebo or usual care for the prevention of post-operative atrial fibrillation in post-coronary artery bypass grafting or combined CABG and valvular surgery.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Fifty eight studies were included with a total of 8565 participants. Interventions included were amiodarone, beta blockers, solatol and pacing. Results favoured treatment for post-operative atrial fibrillation. The data for stroke favoured treatment by a non-significant effect size of 0.81, 95% confidence interval 0.51 to 1.28. Similarly, a positive indication for length of stay was derived but it too was not significant with a weighted mean difference of -0.66, 95% confidence interval -0.95 to -0.37. A positive result for cost of hospitalisation in favour of treatment was achieved, but the statistic is not significant due to low power and large standard deviations: a weighted mean difference of -2717, 95% confidence interval 7518 to 2084. Beta-blockers had the greatest magnitude of effect across 28 trials (4074 patients) with an odds ratio (random) of 0.35, 95% confidence interval 0.26 to 0.49. Across all treatment, the odds ratio favoured treatment with a ratio (random) of 0.43, 95% confidence interval 0.37 to 0.51.

REVIEWERS' CONCLUSIONS

Intervention is favoured across the three pharmacological interventions studied and the one non-pharmacological intervention, pacing. The length of stay data favoured treatment (-0.66, 95% confidence interval -0.95 to -0.37).

Postoperative atrial fibrillation and mortality after coronary artery bypass surgery

OBJECTIVES

We sought to determine if the occurrence of postoperative atrial fibrillation (AF) affects early or late mortality following coronary artery bypass surgery (CABG).

BACKGROUND

Atrial fibrillation is the most common arrhythmia seen following CABG.

METHODS

The Texas Heart Institute Cardiovascular Research Database was used to identify all patients that developed AF after isolated initial CABG from January 1993 to December 1999 (n = 994). This population was compared with patients who underwent CABG during the same period but did not develop AF (n = 5,481). In-hospital end points were adjusted using logistic regression models to account for baseline differences. Long-term survival was evaluated using a retrospective cohort design, where Cox proportional hazards methods were used to adjust for baseline differences, and with case-matched populations (n = 390, 195 per arm).

RESULTS

Atrial fibrillation was diagnosed in 16% of the population. Postoperative AF was associated with greater in-hospital mortality (odds ratio [OR] 1.7, p = 0.0001), more strokes (OR 2.02, p = 0.001), prolonged hospital stays (14 vs. 10 days, p < 0.0001), and a reduced incidence of myocardial infarction (OR 0.62, p = 0.01). At four to five years, survival was worse in patients who developed postoperative AF (74% vs. 87%, p < 0.0001 in the retrospective cohort; 80% vs. 93%, p = 0.003 in the case-matched population). On multivariate analysis, postoperative AF was an independent predictor of long-term mortality (adjusted OR 1.5, p < 0.001 in the retrospective cohort; OR 3.4, p = 0.0018 in the case-matched population).

CONCLUSIONS

The occurrence of AF following CABG identifies a subset of patients who have a reduced survival probability following CABG. The impact of various strategies, such as antiarrhythmics and warfarin, aimed at reducing AF and its complications deserves further study.

Atrial fibrillation after cardiac surgery: evidence on prophylactic interventions

Postoperative atrial fibrillation after heart surgery is frequent and may increase the length of hospital stay and costs of postoperative care of patients after heat surgery. Pharmacological and pacing interventions were evaluated in the large number of relatively small trials with often contradictory results. Conventional beta-blockers, sotalol, amiodarone and pacing were shown to be equally effective in the prevention of postoperative atrial fibrillation. Amiodarone and bi-atrial pacing were also effective in decreasing the length of hospital stay.

Incidence and clinical consequences of atrial fibrillation within 1 year of first-time isolated coronary bypass surgery

BACKGROUND

Atrial fibrillation (AF) is the commonest complication during cardiac surgery, however, the long-term prevalence of AF following surgery and its clinical consequences remain unclear.

PATIENTS AND METHODS

To investigate this, 877 consecutive patients undergoing first time CABG were followed for 1 year. Rhythm disturbances were diagnosed from serial ECGs and documented notes. The arrhythmia was treated medically and/or by cardioversion.

RESULTS

Out of 877, 17 patients (1.9%) died in the hospital and out of the remaining 860 patients 844 (98.1%) had a complete 1-year follow-up. Patients were divided according to their age: Group I (50 to 59 years), Group II (60 to 69 years) and Group III (70 to 79 years). The prevalence of AF in the general population was taken from the Framingham Heart Study. Patients in groups I and II had a higher incidence of AF before the operation than the general population (1.5% versus 0.4% and 3.1% versus 1.6%, respectively, P<0.05) and also higher incidence of AF at the 1-year follow-up (2% versus 0.4% and 4.6% versus 1.6% respectively, P<0.05). The incidence of AF in group III did not differ from the general population before operation, at the 6-week and 1-year follow-ups. As expected most of the patients with preoperative AF remained in AF after 1-year of CABG surgery. Importantly, the incidence of newly developed AF was higher in patients that developed infection and renal dysfunction in the postoperative period. AF did not predict embolic events at any stage of the study.

CONCLUSIONS

In conclusion, the incidence of AF for the first year following CABG is higher in patients <70 years but not in those >70 years when compared with the general population. AF was also associated to the occurrence of postoperative infection and renal dysfunction. Patients in this study were closely monitored and received timely appropriate treatment, and this may account for the absence of a relationship between AF and embolic events.

Incidence, Timing, Symptoms, and Risk Factors for Atrial Fibrillation After Cardiac Surgery

• Background Atrial fibrillation is the most common complication after cardiac surgery and a major cause of morbidity and increased cost of care.

• Objectives To examine the incidence, timing, symptoms, and risk factors for atrial fibrillation after cardiac surgery.

• Methods A total of 302 patients were continuously monitored for atrial fibrillation with standard hardwire and telemetry devices during hospitalization after coronary artery bypass graft and/or valve surgery and with wearable cardiac event recorders for 2 weeks after discharge from the hospital. After discharge, patients recorded and transmitted their rhythm by telephone daily and whenever they had symptoms suggestive of atrial fibrillation.

• Results Of the 302 patients, 127 (42%) had atrial fibrillation; 41 had it after discharge, and for 10 it was their first episode. The first episode occurred at a mean of 2.9 days after surgery (SD, 3.1; range, day of surgery to 21 days after surgery). Although palpitations was the most common symptom (17%), most episodes of atrial fibrillation (69%) were not associated with symptoms. Independent predictors of atrial fibrillation were age 65 years or greater, history of intermittent atrial fibrillation, atrial pacing, male sex, white race, and not having hyperlipidemia. Independent predictors of atrial fibrillation after discharge from the hospital were having atrial fibrillation while hospitalized, valve surgery, and pulmonary hypertension.

• Conclusions Atrial fibrillation is common after cardiac surgery and often occurs after discharge from the hospital and without accompanying symptoms. Outpatient monitoring may be warranted in patients with characteristics that place them at increased risk for atrial fibrillation.

Double-blind, placebo-controlled, randomized trial of prophylactic metoprolol for reduction of hospital length of stay after heart surgery: the beta-Blocker Length Of Stay (BLOS) study

BACKGROUND

Atrial fibrillation (AF) is a common complication of heart surgery. Previous studies have shown that there is an association between postoperative AF and prolongation of hospital length of stay. No previous trials have been primarily directed at demonstrating that the use of drugs that prevent AF would shorten length of stay and reduce the costs of postoperative care.

METHODS

A randomized, double-blind, placebo-controlled trial of metoprolol was performed in patients immediately after nonemergent heart surgery. Metoprolol was given orally at a dose of 100 mg per day after the patient's arrival in the intensive care unit until hospital discharge or 14 days, whichever was sooner. This dose was increased to 150 mg per day after the enrollment of 411 patients. The primary outcome measure of the study was hospital length of stay from admission to intensive care unit until hospital discharge. There were 1000 patients enrolled, evenly distributed to the metoprolol and placebo groups.

RESULTS

There was a 20% reduction in the risk of AF developing with metoprolol, from 39% of patients to 31% of patients (P =.01). There was no effect of treatment on hospital length of stay, which was 152 +/- 61 hours for placebo and 155 +/- 90 hours for metoprolol (P = 0.79). The cost of postoperative care in the 2 treatment groups was similar.

CONCLUSION

Prophylactic metoprolol reduces the risk of AF after heart surgery. It does not reduce hospital length of stay. Although it is cost effective for the reduction of AF, it did not reduce the overall cost of care.