Atrial fibrillation after coronary artery bypass grafting: does the type of procedure influence the early postoperative incidence?

Preoperative B-Type Natriuretic Peptides to Predict Postoperative Atrial Fibrillation in Cardiac Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

Post-operative atrial fibrillation (AF) is the most common complication following cardiac surgery. There has been extensive exploration of clinical variables, imaging, and biomarkers to predict its occurrence after cardiac surgery. In this study, we examine the emerging biomarkers B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) to assess their pre-operative values and correlations with the occurrence of post-operative AF in patients undergoing cardiac surgery.

METHODS

A comprehensive literature search was conducted using PubMed, EMBASE, MEDLINE via Ovid, ClinicalTrials.Gov, Scopus, and Cochrane Central Register of Controlled Trials (CENTRAL) to identify studies published until March 2023. The studies were included if they reported pre-operative BNP or NT-proBNP values and the development of post-operative AF in cardiac surgery patients. Subsequently, data were extracted, and a meta-analysis was performed using Review Manager 5.4 4 (The Cochrane Collaboration, 2020) and SPSS version 28 (IBM Corp, Armonk, NY, USA) to assess the difference between pre-operative BNP and NT-proBNP levels between patients with post-operative AF (AF group) and those without (No-AF group) using a random-effect model. Further analysis was performed in three subgroups: isolated coronary artery bypass grafting, isolated valve, and combined/mixed surgery group.

RESULT

A total of 20 studies, including 9,079 participants were identified and included in the systematic review and meta-analysis. Pre-operative BNP levels were reported in 11 studies, and NT-proBNP levels were reported in 10 studies, of which one study reported both BNP and NT-proBNP levels. There is an overall significant difference between pre-operative levels of BNP (p=0.03, I2=95%) and NT-proBNP (p<0.001, I2=65%) when compared between AF and No-AF groups. Nonetheless, subgroup analysis showed there is no significant difference in pre-operative BNP levels, except in isolated valve surgery (p<0.001), whereas all subgroups showed significantly different pre-operative levels of NT-proBNP.

CONCLUSIONS

Elevated levels of both BNP and NT-proBNP were observed in patients who developed post-operative AF after undergoing cardiac surgery. In particular, pre-operative NT-proBNP levels were elevated in all patients irrespective of the type of surgical procedure, but elevated pre-operative BNP was only seen in valve surgery patients. These findings suggest the potential usefulness of NT-proBNP as a promising biomarker for predicting the occurrence of post-operative AF following cardiac surgery.

Impact of sleep disordered breathing on postoperative atrial fibrillation in patients who underwent cardiac surgery: a meta-analysis

Objective: An increasing number of studies suggest that sleep disordered breathing (SDB) may be associated with postoperative atrial fibrillation (POAF), but these studies present discrepant results. Thus, this meta-analysis aimed to synthesize the data associating SDB with POAF in patients who underwent cardiac surgery.Methods: A literature search was performed in the Scopus, PubMed, Web of Science, EMBASE, CENTRAL, Weipu, Wanfang Data, and China National Knowledge Infrastructure databases before August 2022. Data were extracted, and the strength of the relationship between SDB and the risk of POAF was evaluated using odds ratio (OR) and 95% confidence intervals (CIs). All statistical analysis was carried out using the Stata 12.0 software.Results: A total of 24 studies with 660,685 subjects were included in current meta-analysis. SDB was significantly associated with the risk of POAF in the patients who underwent cardiac surgery (OR = 1.49; 95% CI, 1.30-1.70; p < .001). Next subgroup analysis revealed that such association may be increased in the group with medical equipment-measured SDB (OR = 2.27; 95% CI, 1.59-3.23; p < .001), prospective studies (OR = 2.17; 95% CI, 1.55-3.03; p < .001), patients without a previous history of atrial fibrillation (OR = 2.04; 95% CI, 1.47-2.82; p < .001), and patients who received a coronary artery bypass graft (OR = 2.10; 95% CI, 1.45-3.05; p < .001). No publication bias was identified.Conclusion: The results of meta-analysis support that SDB may be associated with an increased risk of POAF in patients who had undergone cardiac surgery, and these results should be confirmed in more rigorously designed studies.KEY MESSAGESPatients with SDB who underwent cardiac surgery showed increased risk of POAF.The relationship between SDB and POAF should be explained with caution with the consideration of various covariate.The effect of pre-treatment of SDB on POAF should be examined in future.

Impact of Denervation by Heart Transplantation on Post-operative Atrial Fibrillation Susceptibility

Atrial fibrillation is common following cardiac and non-cardiac thoracic surgery and is associated with poorer outcomes, including: increased risk of stroke, hemodynamic instability, prolonged hospital stay, and increased mortality. Current understanding suggests that post-op atrial fibrillation results from the interplay of local and systemic operative inflammation, increased sympathetic activity, perhaps the release of free radical species in the perioperative period, and the patient's underlying cardiac substrate. Cardiac denervation following orthotopic heart transplant (OHT) using modern bicaval techniques presents a unique opportunity to study the relative contribution of the autonomic nervous system to post-op atrial fibrillation susceptibility. Observational studies show a reduced incidence of post-operative atrial fibrillation following orthotopic heart transplant compared to other cardiac and thoracic surgeries. Moreover, comparison of atrial fibrillation rates with double lung transplant recipients suggests that cardiac denervation has a contribution apart from surgical pulmonary vein isolation alone. This report reviews current concepts of the mechanisms of post-op atrial fibrillation with a focus on the role of the autonomic nervous system, the autonomic regulation of the native heart, and evidence regarding the impact of cardiac denervation following OHT.

Clinical burden associated with postsurgical complications in major cardiac surgeries in Asia-Oceania countries: A systematic review and meta-analysis

BACKGROUND

Evidence on the burden of postsurgical complications is mainly from studies in western countries, and little is highlighted in the Asia-Oceania region. This study aimed to identify and compare the burden of postsurgical complications in major cardiac surgeries in Asia-Oceania countries.

METHODS

A systematic search was performed in PubMed, Embase, and CENTRAL between January 2000 and July 2018. Inclusion criteria were: (a) observational studies or randomized control trials; (b) studied in coronary artery bypass graft (CABG) and/or heart valve procedures; (c) measured postsurgical clinical outcomes; and (d) conducted in Asia-Oceania countries. Pooled effects were calculated using a random-effects model.

RESULTS

Of the 6032 articles screened, 472 studies with a total of 614 161 patients met the inclusion criteria. The pooled incidences (95% confidence interval) of hospital mortality and 30-day mortality were similar at 2.38% (2.16%-2.59%) and 2.33% (2.16%-2.50%), respectively. Length of stay (LOS) was 14.07 days (13.44-14.71 days). The incidence for atrial fibrillation (AF) and stroke/cerebrovascular accident (CVA) was 17.49% (15.99%-18.99%) and 1.64% (1.51%-1.78%), respectively. Below outcomes tended to be better in studies on CABG compared to heart valve procedures, including the incidence of hospital mortality (1.97%[1.75%-2.18%] vs 3.97% [3.29%-4.65%]), AF (16.47% [14.85%-18.10%] vs 21.98% [17.41%-26.54%]), stoke/CVA (1.51% [1n 37%-1.65%] vs 2.55% [2.07%-3.04%]), and mean LOS (days) (13.08 [12.51-13.65] vs 19.58 [16.72-22.45]). Similarly, all postsurgical complications tended to be higher in studies involving high-risk patients vs non-high-risk patients.

CONCLUSIONS

There are opportunities to improve clinical outcomes of patients with high surgical risks and those undertaking heart valve procedures, as they tend to have poorer survival and higher risk in developing postsurgical complications.

Fragmented QRS complexes are associated with postoperative atrial fibrillation development after coronary artery bypass grafting surgery

OBJECTIVE

Postoperative atrial fibrillation (PoAF) is one of the most frequent complications and a major risk factor of morbidity and mortality after coronary artery bypass grafting (CABG). Fragmented QRS complex (fQRS) on a 12-lead surface ECG is recently gained increasing attention as a simplified noninvasive ECG marker with diagnostic and prognostic value in various cardiac conditions. The aim of the present study was to evaluate the association between development of PoAF and presence of fQRS on admission ECG in patients undergoing CABG surgery.

METHODS

A total of 242 patients who underwent CABG between February 2016 and June 2018 were included in this study. The patients were divided into two groups as developing and nondeveloping PoAF groups in the postoperative period. fQRS was defined as the presence of various RSR' patterns including an additional R wave, notching of the R or S waves, or the presence of more than one fragmentation in two contiguous leads.

RESULTS

In-hospital mortality was higher in PoAF (+) group compared to PoAF (-) group (20.5 vs. 6.4%, P = 0.004). PoAF rate was higher in fQRS (+) group than fQRS (-) group (25.3 vs. 9.8%, P = 0.001). In multivariate analysis, the presence of fQRS complexes on admission ECG [odds ratio (OR) 2.801, 95% confidence interval (CI) 1.262-6.211, P = 0.011) and hemoglobin (OR 0.794; 95% CI, 0.641-0.985; P = 0.036) were identified as independent predictors of PoAF after CABG surgery.

CONCLUSION

The presence of fQRS on admission ECG was found to be an independent predictor of PoAF in patients undergoing isolated CABG.

Clinical significance and risk factors for new onset and recurring atrial fibrillation following cardiac surgery - a retrospective data analysis

Background

Although mortality after cardiac surgery has significantly decreased in the last decade, patients still experience clinically relevant postoperative complications. Among others, atrial fibrillation (AF) is a common consequence of cardiac surgery, which is associated with prolonged hospitalization and increased mortality.

Methods

We retrospectively analyzed data from patients who underwent coronary artery bypass grafting, valve surgery or a combination of both at the University Hospital Muenster between April 2014 and July 2015. We evaluated the incidence of new onset and intermittent/permanent AF (patients with pre- and postoperative AF). Furthermore, we investigated the impact of postoperative AF on clinical outcomes and evaluated potential risk factors.

Results

In total, 999 patients were included in the analysis. New onset AF occurred in 24.9% of the patients and the incidence of intermittent/permanent AF was 59.5%. Both types of postoperative AF were associated with prolonged ICU length of stay (median increase approx. 2 days) and duration of mechanical ventilation (median increase 1 h). Additionally, new onset AF patients had a higher rate of dialysis and hospital mortality and more positive fluid balance on the day of surgery and postoperative days 1 and 2. In a multiple logistic regression model, advanced age (odds ratio (OR) = 1.448 per decade increase, p < 0.0001), a combination of CABG and valve surgery (OR = 1.711, p = 0.047), higher C-reactive protein (OR = 1.06 per unit increase, p < 0.0001) and creatinine plasma concentration (OR = 1.287 per unit increase, p = 0.032) significantly predicted new onset AF. Higher Horowitz index values were associated with a reduced risk (OR = 0.996 per unit increase, p = 0.012). In a separate model, higher plasma creatinine concentration (OR = 2.125 per unit increase, p = 0.022) was a significant risk factor for intermittent/permanent AF whereas higher plasma phosphate concentration (OR = 0.522 per unit increase, p = 0.003) indicated reduced occurrence of this arrhythmia.

Conclusions

New onset and intermittent/permanent AF are associated with adverse clinical outcomes of elective cardiac surgery patients. Different risk factors implicated in postoperative AF suggest different mechanisms might be involved in its pathogenesis. Customized clinical management protocols seem to be warranted for a higher success rate of prevention and treatment of postoperative AF.

Electronic supplementary material

The online version of this article (10.1186/s12871-017-0455-7) contains supplementary material, which is available to authorized users.

Atrial Fibrillation is Associated with Increased Pacemaker Implantation Rates in the Placement of AoRTic Transcatheter Valve (PARTNER) Trial

Atrial fibrillation (AF) is associated with worse outcomes in many cardiovascular diseases. There are few data examining pacemaker implantation rates and indications in patients with AF who undergo transcatheter aortic valve replacement (TAVR). To examine the impact of AF on the incidence of and indications for pacemakers in patients undergoing TAVR, we evaluated data of 1723 patients without pre-existing pacemakers who underwent TAVR in the Placement of AoRTic TraNscathetER Valve (PARTNER) trial. Permanent pacemaker implantation rates and indications were compared in groups based on baseline and discharge heart rhythm: sinus rhythm (SR) vs. AF. 1211 patients manifested SR at baseline/SR at discharge (SR/SR), 105 SR baseline/AF discharge (SR/AF), and 407 AF baseline/AF discharge (AF/AF). Patients who developed and were discharged with AF (SR/AF) had the highest rates of pacemaker implantation at 30 days (13.7% SR/AF vs. 5.4% SR/SR, p=0.0008 and 5.9% AF/AF, p=0.008) and 1 year (17.7% SR/AF vs. 7.1% SR/SR, p=0.0002 and 8.1% AF/AF, p=0.0034). Conversion from SR to AF by discharge was an independent predictor of increased pacemaker implantation at 30 days (HR 2.19 vs. SR/SR, 95% CI 1.23-3.93, p=0.008) and 1 year (HR 1.91 vs. SR/SR, 95% CI 1.33-3.80). Pacemaker indications differed between groups, with relatively more implanted in the AF groups for sick sinus syndrome (SSS) versus AV block. In conclusion, conversion to AF is an independent predictor of permanent pacemaker implantation in TAVR patients. Indications differ depending on heart rhythm, with patients in AF manifesting clinically significant tachy-brady syndrome versus AV block.

Leukocyte filtration and aprotinin: synergistic anti-inflammatory protection

Cardiopulmonary bypass activates an array of cellular and humoral inflammatory mechanisms that culminate in diverse or organ-specific injury. A manifestation of inflammatory injury to the heart, atrial fibrillation ranks among the most frequent and potentially life-threatening postsurgical complications. Pulmonary manifestations of the inflammatory response are also of major concern. Neutrophils activated by passage through the extracorporeal circuit inflict local injury and provoke the inflammatory cascade by producing oxyradicals and proinflammatory factors. This study tested if a combination of leukocyte depletion and aprotinin suppression of neutrophils could minimize postbypass atrial fibrillation and pulmonary dysfunction. In part one, two randomized groups of 90 patients undergoing primary coronary artery bypass grafting received full Hammersmith aprotinin alone (control group) or combined with leukofiltration (study group) and were prospectively examined. The dual treatment decreased the incidence of postoperative atrial fibrillation (7 of 90, 7.8%) by 67% versus aprotinin alone (21 of 90, 23.3%). Respiratory gas exchange in these patients was assessed from pulmonary shunt fraction. In the first two hours postbypass, pulmonary shunt fraction in the dual treatment group increased 40% less than in the group receiving aprotinin alone (p = 0.002), and subsided more quickly and completely over the next six hours. In part two, the cardiopulmonary bypass group receiving aprotinin+leukofiltration was retrospectively compared with 45 patients undergoing off-pump coronary revascularization. A strong, albeit not statistically significant trend (p= 0.08) toward a lower incidence of atrial fibrillation was found in the dual treatment group versus the off-pump group (8 of 45, 17.8%). These findings suggest that combining mechanical and pharmacologic suppression of the systemic inflammatory response could mitigate its deleterious arrhythmic and pulmonary complications.

Atrial Fibrillation Is Associated With Increased Mortality in Patients Undergoing Transcatheter Aortic Valve Replacement: Insights From the Placement of Aortic Transcatheter Valve (PARTNER) Trial

BACKGROUND

This study sought to evaluate the impact of atrial fibrillation (AF) on clinical outcomes in patients undergoing transcatheter aortic valve replacement.

METHODS AND RESULTS

Data were evaluated in 1879 patients with baseline and discharge ECGs who underwent transcatheter aortic valve replacement in the Placement of AoRTic TraNscathetER Valve (PARTNER) trial. A total of 1262 patients manifested sinus rhythm (SR) at baseline/SR at discharge, 113 SR baseline/AF discharge, and 470 AF baseline/AF discharge. Patients who converted from SR to AF by discharge had the highest rates of all-cause mortality at 30 days (P<0.0001 across all groups; 14.2% SR/AF versus 2.6% SR/SR; adjusted hazard ratio [HR]=3.41; P=0.0002) and over 2-fold difference at 1 year (P<0.0001 across all groups; 35.7% SR/AF versus 15.8% SR/SR; adjusted HR=2.14; P<0.0001). The presence of AF on baseline or discharge ECG was a predictor of 1-year mortality (adjusted HR=2.14 for SR/AF group and HR=1.88 for AF/AF groups; P<0.0001 for both groups versus SR/SR). For patients discharged in AF, those with lower ventricular response (ie, <90 bpm) experienced less 1-year all-cause mortality (HR=0.74; P=0.04).

CONCLUSIONS

After transcatheter aortic valve replacement, the presence of AF at discharge, and particularly, the conversion to AF by discharge and higher ventricular response are associated with increased mortality. These data underscore the deleterious impact of AF, as well as the need for targeted interventions to improve clinical outcomes, in patients undergoing transcatheter aortic valve replacement.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00530894.

Off-Pump Coronary Artery Bypass Surgery

Off-pump coronary artery bypass surgery has been adopted enthusiastically worldwide. However, despite more than 6 years’ experience and refinement, many surgeons use it only sporadically and some hardly at all. This reluctance persists despite support for the procedure because of the lack of properly designed risk models and/or randomized studies. Although it has not been overwhelmingly shown that off-pump surgery is superior to the conventional on-pump procedure, the technique has its place in our specialty. It has been shown to be better for noncritical end points in selected patients in the hands of selected surgeons. That there are differences in surgical skill among surgeons is something we all know but rarely discuss in public. Until now, disparities in skill have been most salient with uncommon and extraordinarily challenging operations. Perhaps the off-pump procedure should be regarded as the “challenging” aspect of coronary artery bypass surgery, and self-restraint may need to remain in force if we are to continue to achieve the highest level of clinical excellence.

Do preoperative C-reactive protein and mean platelet volume levels predict development of postoperative atrial fibrillation in patients undergoing isolated coronary artery bypass grafting?

Introduction

Atrial fibrillation (AF) after coronary artery bypass grafting (CABG) operation is associated with increased risk of prolonged hospitalisation, health expenses and adverse clinical outcomes.

Aim

To investigate the relationship of atrial fibrillation after an isolated coronary artery bypass operation with levels of mean platelet volume and C-reactive protein.

Material and methods

Among 1240 patients who underwent operations for isolated coronary artery bypass grafting with cardiopulmonary bypass between January 2007 and May 2014, 1138 (91.8%) patients with preoperative normal sinusal rhythm were enrolled in the study. Patients were assigned to group 1 (n = 294) comprising patients who developed atrial fibrillation in the first 72 postoperative hours or group 2 (n = 844) comprising patients who remained in normal sinusal rhythm in the postoperative period.

Results

The incidence of postoperative atrial fibrillation was 25.8%. The preoperative mean platelet volume (fl) and C-reactive protein (mg/dl) values in group 1 were 9.1 ±0.5 and 1.1 ±0.9 respectively, while these values were 8.3 ±0.6 and 0.5 ±0.3 respectively in group 2, which was statistically significant (p = 0.0001). Length of stay in the hospital (p = 0.0001) was higher in group 1. The values of mean platelet volume (fl) and mean C-reactive protein (mg/dl) were 9.9 ±0.9 and 30.9 ±3.4 respectively in group 1, while the values of mean platelet volume (fl) and mean C-reactive protein (mg/dl) were 8.8 ±0.6 and 24.9 ±4.8 respectively in group 2 (p = 0.0001 for mean platelet volume, p = 0.0001 for C-reactive protein). The difference between the groups was statistically significant in terms of postoperative neurologic events (p = 0.0001) and hospital mortality (p = 0.001). Increased C-reactive protein and mean platelet volume levels were found to be independent predictors of postoperative atrial fibrillation.

Conclusions

In our study, elevated preoperative mean platelet volume and C-reactive protein levels were associated with development of postoperative atrial fibrillation.

The role of N-terminal pro-brain natriuretic peptide in prediction of postoperative atrial fibrillation

AIM

To analyze prognostic value of different factors in postoperative atrial fibrillation prediction.

MATERIAL AND METHODS

Study included 39 patients with coronary artery disease without previous paroxysmal atrial fibrillation. Multiple correlation, logistic regression and ROC-analysis were performed to create predictive model of postoperative atrial fibrillation prognosis. Authors have analyzed most of described in literature preoperative predictors of atrial fibrillation to define the role of different risk factors. Prognostic role of N-terminal pro-brain natriuretic peptide (NT-proBNP) is assessed.

RESULTS

We revealed high informativeness of NT-proBNP to predict postoperative atrial fibrillation after on-pump coronary artery bypass grafting.

The influence of epidural anesthesia on the electrical activity of heart atria

Introduction

High thoracic epidural anesthesia (TEA) causes blockade of sympathetic fibers involved in innervation of the heart (segments T1-T4), which results in changes of cardiac electrophysiology. The anti-arrhythmic effects of TEA on supraventricular arrhythmias, mainly atrial fibrillation, are controversial.

The aim of the study

The aim of the study was to assess the influence of epidural anesthesia on the electrical function of heart atria, including proven markers of increased risk of perioperative atrial fibrillation, such as P wave dispersion and P wave maximum duration.

Material and methods

The study involved 50 male patients, without a history of previous heart diseases, scheduled for elective surgical procedures. Patients received thoracic epidural anesthesia (group T, n = 25) or lumbar epidural anesthesia (group L, n = 25). The measurements were obtained from a continuous recording of ECG before epidural anesthesia and after the detection of blockade (T1 or T8 segment sensory block in groups T and L, respectively).

Results

The statistical analysis of electrocardiographic parameters, including the maximum, minimum and mean P wave duration; P wave dispersion; the maximum, minimum and mean PR interval duration; and PR interval dispersion, did not show any inter- or intragroup differences at selected time points.

Conclusions

Regardless of its location, epidural anesthesia and sympathetic blockade associated with this procedure do not significantly affect the electrical functions of the cardiac atria reflected in superficial ECG, including the electrocardiographic parameters that are considered to be markers of increased risk of perioperative atrial fibrillation, such as P wave dispersion and its maximum duration.

Genetic diversity of the KCNE1 gene and susceptibility to postoperative atrial fibrillation

BACKGROUND

The human KCNE1 protein forms the β-subunit of the IKs potassium channel and is important in the regulation of the atrial action potential duration. The purpose of this study was to investigate the association between the nonsynonymous 112G>A mutation of the KCNE1 gene and postcardiac surgery atrial fibrillation (AF).

METHODS AND RESULTS

A cohort of patients scheduled for cardiac surgery was prospectively recruited. The genotype of 112G>A polymorphism was determined using polymerase chain reaction/restriction fragment analysis and confirmed with direct sequencing of the polymerase chain reaction product. In total, 509 patients were recruited in the study, of whom 203 (39.9%) had at least 1 qualifying episode of postoperative AF. An increased frequency of the G allele was observed in the postoperative AF group compared with the group without postoperative AF (0.628 vs 0.552, respectively, P = .016). The individual's relative risk of postoperative AF increased as the number of G alleles increased from 1.36 (95% CI 0.89-2.08) for G allele heterozygotes to 1.62 (95% CI 1.08-2.43) for G allele homozygotes (P = .04 for trend). The multivariate analysis revealed the abnormal ejection fraction (odds ratio [OR] 1.585, 95% CI 1.076-2.331, P = .020), age (OR 1.043, 95% CI 1.022-1.064, P < .001), type of surgery (aortic valve replacement) (OR 1.869, 95% CI 1.094-3.194, P = .022), and the 112G>A genotype (OR 1.401 [in additive model], 95% CI 1.052-1.865, P = .021) to be independent predictors of postoperative AF.

CONCLUSION

This study confirmed the association of the 112G>A polymorphism and postoperative AF in a cohort of patients undergoing cardiac surgery.

U-shaped relationship between tissue docosahexaenoic acid and atrial fibrillation following cardiac surgery

BACKGROUND/OBJECTIVES

Randomised controlled trials (RCTs) evaluating the effect of fish oil supplementation on postoperative atrial fibrillation (POAF) following cardiac surgery have produced mixed results. In this study, we examined relationships between levels of red blood cell (RBC) n-3 long-chain polyunsaturated fatty acids (LC-PUFAs) and the incidence of POAF.

SUBJECTS/METHODS

We used combined data (n=355) from RCTs conducted in Australia and Iceland. The primary end point was defined as POAF lasting >10 min in the first 6 days following surgery. The odds ratios (ORs) for POAF were compared between quintiles of preoperative RBC n-3 LC-PUFA levels by multivariable logistic regression.

RESULTS

Subjects with RBC docosahexaenoic acid (DHA) in the fourth quintile, comprising a RBC DHA range of 7.0-7.9%, had the lowest incidence of POAF. Subjects in the lowest and highest quintiles had significantly higher risk of developing POAF compared with those in the fourth quintile (OR=2.36: 95% CI; 1.07-5.24 and OR=2.45: 95% CI; 1.16-5.17, respectively). There was no association between RBC eicosapentaenoic acid levels and POAF incidence.

CONCLUSIONS

The results suggest a 'U-shaped' relationship between RBC DHA levels and POAF incidence. The possibility of increased risk of POAF at high levels of DHA suggests an upper limit for n-3 LC-PUFAs in certain conditions.

Does Off-pump Coronary Artery Bypass Reduce the Prevalence ofAtrial Fibrillation?

INTRODUCTION

To examine whether or not off-pump CABG (Coronary Artery Bypass Reduce) reduces the incidence of AF after cardiac surgery.

METHODS

The study was carried out in 939 consecutive coronary artery disease patients with sinus rhythm from which 383 patients underwent off-pump CABG, and 556 patients were operated through on-pump CABG. All patients were monitored postoperatively during intensive care unit (ICU) stay. Then, the incidence and predictive risk factors of post operative AF (POAF) in two groups were determined and compared with each other.

RESULTS

Overall, the mean age of the patients was 56.0±12.8 years with 234 patients (24.9%) being older than 65 years. POAF developed in 38 patients (9.9%) of the off-pump and in 93 patients (16.7%) of the on-pump CABG. There was significant difference between two groups when considering the incidence of POAF (P=0.002). Among preoperative risk factors, age>65 years had a significant association with the incidence of AF in both groups. This study also showed that most of the POAF cases converted to sinus rhythm after treatment. Moreover, these finding demonstrated that conversion to sinus rhythm is significantly more probable in off-pump group (P=0.006).

CONCLUSION

A reduced prevalence of POAF could be observed in patients with off-pump as compared with on-pump techniques. Furthermore, conversion to sinus rhythm in off-pump group was significantly more probable than on-pump group.

Ischemia-modified albumin use as a prognostic factor in coronary bypass surgery

BACKGROUND

Various types of markers have been used so far in order to reveal myocardial perfusion defect. However, these markers usually appear in the necrosis phase or in the late stage. Having been the focus of various investigations recently, ischemia-modified albumin (IMA) is helpful in establishing diagnosis in the early stages of ischemia, before necrosis develops.

METHODS AND RESULTS

30 patients that underwent only coronary bypass surgery due to ischemic heart disease within a specific period of time have been included in the study. IMA levels were studied in the preoperative, intraoperative, and postoperative periods. The albumin cobalt binding assay was used for IMA determination. Hemodynamic parameters (atrial fibrillation, the need for inotropic support, ventricular arrhythmia) of the patients in the postoperative stage were evaluated. Intraoperative measurement values (mean ± SD) of IMA (0.67677 ± 0.09985) were statistically significantly higher than those in the preoperative (0.81516 ± 0.08894) and postoperative (0.70477 ± 0.07523) measurements. Considering atrial fibrillation and need for inotropics, a parallelism was detected with the levels of IMA.

CONCLUSIONS

IMA is an early-rising marker of cardiac ischemia and enables providing a direction for the treatment at early phases.

Effect of dietary fish oil on atrial fibrillation after cardiac surgery

An open-label study reported that ingestion of a fish oil concentrate decreased the incidence of atrial fibrillation (AF) after coronary artery bypass grafting (CABG) surgery. However, a general cardiac surgery population involves valve and CABG surgeries. We undertook a double-blinded randomized controlled trial to examine the effectiveness of fish oil supplementation on the incidence of postsurgical AF after CABG and valve procedures. The primary end point was incidence of AF in the first 6 days after surgery. Two hundred patients were randomized to receive fish oil (providing 4.6 g/day of long-chain ω-3 fatty acids) or a control oil starting 3 weeks before surgery; 194 subjects completed the study, with 47 of 97 subjects in the control group and 36 of 97 subjects in the fish oil group developing AF (odds ratio 0.63, 95% confidence interval [CI] 0.35 to 1.11). There was a nonstatistically significant delay in time to onset of AF in the fish oil group (hazard ratio 0.66, 95% CI 0.43 to 1.01). There was a significant decrease in mean length of stay in the intensive care unit in the fish oil group (ratio of means 0.71, 95% CI 0.56 to 0.90). In conclusion, in a mixed cardiac surgery population, supplementation with dietary fish oil did not result in a significant decrease in the incidence of postsurgical AF. However, there was a significant decrease in time spent in the intensive care unit.

Post-operative atrial fibrillation: a maze of mechanisms

Post-operative atrial fibrillation (POAF) is one of the most frequent complications of cardiac surgery and an important predictor of patient morbidity as well as of prolonged hospitalization. It significantly increases costs for hospitalization. Insights into the pathophysiological factors causing POAF have been provided by both experimental and clinical investigations and show that POAF is ‘multi-factorial’. Facilitating factors in the mechanism of the arrhythmia can be classified as acute factors caused by the surgical intervention and chronic factors related to structural heart disease and ageing of the heart. Furthermore, some proarrhythmic mechanisms specifically occur in the setting of POAF. For example, inflammation and beta-adrenergic activation have been shown to play a prominent role in POAF, while these mechanisms are less important in non-surgical AF. More recently, it has been shown that atrial fibrosis and the presence of an electrophysiological substrate capable of maintaining AF also promote the arrhythmia, indicating that POAF has some proarrhythmic mechanisms in common with other forms of AF. The clinical setting of POAF offers numerous opportunities to study its mechanisms. During cardiac surgery, biopsies can be taken and detailed electrophysiological measurements can be performed. Furthermore, the specific time course of POAF, with the delayed onset and the transient character of the arrhythmia, also provides important insight into its mechanisms.

This review discusses the mechanistic interaction between predisposing factors and the electrophysiological mechanisms resulting in POAF and their therapeutic implications.

Body mass index predicts new-onset atrial fibrillation after cardiac surgery

OBJECTIVE

New-onset postoperative atrial fibrillation (POAF) after cardiac surgery is associated with increased morbidity and mortality. Since obesity is becoming increasingly prevalent, identifying body mass index (BMI) as a risk factor for POAF could be of importance. The aim of our study is to investigate the effect of BMI on POAF, independent of other risk factors.

METHODS

We analyzed data of 6788 men and 2560 women who underwent coronary artery bypass grafting, valve surgery, or a combination of both, and who had no history of atrial fibrillation. Men and women were analyzed separately because risk factors of POAF were expected to be distributed unequally over both sexes.

RESULTS

The independent effect of gender was analyzed in a combined model. POAF occurred in 2517/9348 (27%) of patients. Multivariate logistic regression analyses showed that BMI (odds ratio (OR) 1.03; 95% confidence interval (CI): 1.01-1.04; p<0.001 in men and OR 1.03; 95% CI: 1.02-1.05; p<0.001 in women), age (OR 1.06; 95% CI: 1.05-1.07; p<0.001 in men and OR 1.05; 95% CI: 1.04-1.06; p<0.001 in women), valve surgery compared to coronary surgery (e.g., mitral valve surgery compared to coronary artery bypass grafting: OR 3.4; 95% CI: 2.4-4.6; p<0.001 in men and OR 2.9; 95% CI: 2.0-4.3; p<0.001 in women) and male gender (OR 1.23; 95% CI: 1.09-1.38; p=0.001) were the only independent risk factors for POAF, whereas chronic obstructive pulmonary disease, hypertension, off-pump coronary artery bypass grafting, extra corporal circulation time, and transfusion of blood products were not.

CONCLUSION

Body mass index, age, undergoing valve surgery and male gender, are independent risk factors for POAF.

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.

Impact of high thoracic epidural anesthesia on incidence of perioperative atrial fibrillation in off-pump coronary bypass grafting: A prospective randomized study

OBJECTIVE

Atrial fibrillation is one of the most common complications in patients undergoing coronary artery bypass grafting. The goal of this study was to investigate the impact of high thoracic epidural anesthesia on reduction of perioperative arrhythmia in patients undergoing off-pump coronary artery bypass grafting.

METHODS

We prospectively randomized 132 patients undergoing elective off-pump coronary bypass grafting using either general anesthesia (GA) (n = 66) or combined general and high thoracic epidural anesthesia (GA+TEA) (n = 66). Incidence of perioperative arrhythmias such as atrial fibrillation, serum epinephrine levels, heart rate variability, and hemodynamic parameters were compared between groups.

RESULTS

The incidence of perioperative dysarrhythmias was significantly lower (P < .01) in the GA+TEA group (3%) than in the GA group (23.7%). Intraoperative sinus bradycardia occurred in 91% of the patients in the GA+TEA group versus 5.3% in the GA group. After induction of anesthesia, the mean systolic arterial pressure decreased significantly from 128 +/- 5 to 92 +/- 4 mm Hg and the heart rate from 74 +/- 9 to 52 +/- 8 beats . min(-1) in the GA+TEA group, whereas in the GA group no significant hemodynamic changes were observed (P < .001). Serum epinephrine levels were significantly lower in the GA+TEA group (69 +/- 11 to 35 +/- 7 ng/dL) than in the GA group (72 +/- 9 to 70 +/- 9 ng/dL).

CONCLUSIONS

In our study cohort, high thoracic epidural anesthesia in combination with general anesthesia reduced significantly the incidence of perioperative arrhythmias such as atrial fibrillation. Furthermore, we observed a significant reduction of epinephrine serum levels in this patient group. The results of this study support a combination of general anesthesia with thoracic epidural anesthesia as a multidisciplinary approach, which may lead to a better patient outcome, improvement of early analgesia, and reduction of perioperative complications in off-pump coronary artery bypass procedures. The potential risks of thoracic epidural anesthesia during off-pump coronary artery bypass procedures should not be underestimated.

Predictors of Early Postoperative Atrial Fibrillation after Off-Pump Myocardial Revascularization

Objective

We determined the incidence and the predisposing factors of atrial fibrillation (AF) after aorta nontouch coronary artery bypass grafting without extracorporeal circulation.

Methods

From February 2001 to November 2005, 1359 patients (1159 men, 85.3%) of mean (±SD) age 64.8 (±9.8) years, who underwent off-pump coronary artery bypass grafting (OP-CAB), were prospectively enrolled. Demographics, perioperative data, and comorbidities were recorded in all patients. A 24-hour rhythm monitoring was performed in all patients until hospital discharge.

Results

Among 1359 patients, 273 (20.1%) had development of atrial fibrillation in the early postoperative period. Patients with AF had higher mean (±SD) age, 68.3 (±8.8) years, compared with control subjects [63.9 (± 9.9)] (P ≤ 0.0005). Univariate analysis showed that apart from age, history of arterial hypertension (P ≤ 0.02), chronic obstructive pulmonary disease (P ≤ 0.02), and the use of bilateral internal mammary arteries (P≤< 0.01) were predisposing factors for the development of AF. Logistic regression analysis showed that age, history of arterial hypertension, and the use of bilateral internal mammary arteries were predisposing factors for early postoperative AF after OP-CAB.

Conclusions

Atrial fibrillation occurred in approximately 20% of patients undergoing OP-CAB, mainly in older patients with arterial hypertension who received bilateral internal mammary artery grafts.

Red Cell Transfusion is Associated With an Increased Risk for Postoperative Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is a common complication after cardiac surgery and is associated with increased resource utilization. Recent evidence supports a role of inflammation in the development of AF. It is also known that red blood cell transfusion modulates inflammation by increasing plasma levels of inflammatory markers. Therefore, we tested the hypothesis that red blood cell transfusion increases the risk of postoperative AF for patients undergoing cardiac surgery.

METHODS

Between February 2002 and January 2005, 5,841 patients underwent isolated coronary artery bypass grafting with or without valve replacement. Patient and procedural variables associated with development of new-onset AF were identified by logistic regression. Propensity score matching was used to confirm results.

RESULTS

In addition to older age, prior history of AF, higher preoperative hematocrit, beta-blocker withdrawal, longer aortic clamp time, valve surgery, and intensive care unit inotropic usage, intensive care unit red blood cell transfusion increased risk for AF (odds ratio per unit transfused, 1.18; 95% confidence limits, 1.14, 1.23; p < 0.0001). For the 1,360 propensity-matched pairs, intensive care unit red blood cell transfusion was associated with a significant increase in new-onset AF (620 [46%] versus 522 [38%]; p < 0.001).

CONCLUSIONS

Intensive care unit red blood cell transfusion is associated with increased occurrence of postoperative AF after cardiac surgery. This factor should be considered in identifying patients who might benefit from prophylaxis to prevent this common postoperative complication.

Cellular inflammatory response and clinical outcome in cardiac surgery

PURPOSE

This review briefly summarizes recent advances in the understanding of the pathophysiology of the inflammatory response to cardiac surgery and its ties to clinical outcomes. Links between specific inflammatory mediators and vulnerable organs will be emphasized, along with genetic risk factors that render specific patients susceptible to these complications.

RECENT FINDINGS

Circulation of blood on the cardiopulmonary bypass circuit and the operative procedure itself provoke activation of circulating hematopoietic cells and vascular endothelial cells. These activated cells subsequently secrete mediators that amplify this inflammatory response and activated phagocytes undergo changes that facilitate their exit from the circulation into tissue, where they exacerbate organ complications of the procedure. Cardiac, renal and pulmonary dysfunction are among the most common complications of cardiac surgery and progress has been made in recent years demonstrating how the cellular inflammatory response is related to adverse outcomes in these organs. Accordingly, this review will focus on these three systems and the pathophysiology of their cardiac surgical complications.

SUMMARY

Advances in our understanding of the pathways by which inflammatory mediators contribute to host injury offers the promise of interventions that are tailored to specific risks and the possibility of preoperatively identifying those patients most likely to benefit.

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.

Atrial Fibrillation After Cardiac Surgery/Cardiopulmonary Bypass Is Associated with Monocyte Activation

Atrial fibrillation (AF) contributes significantly to morbidity and mortality in as many as one-third of patients after cardiac surgery that requires cardiopulmonary bypass (CPB). Recent data suggest that inflammatory infiltration of the myocardium may predispose to AF. We conducted an exploratory pilot study to determine if there was an association between the perioperative leukocyte inflammatory response to cardiac surgery/CPB and postoperative AF. We enrolled 72 patients undergoing cardiac surgery with CPB; all patients were in sinus rhythm before surgery. Leukocyte activation (CD11b upregulation) was perioperatively measured in monocytes and neutrophils (PMN). Preoperative C-reactive protein (CRP) and perioperative neutrophil myeloperoxidase (MPO) were also monitored for inflammation, and troponin I was assayed for perioperative cardiac muscle damage. All markers were evaluated for differences between the subset of patients who developed AF versus those who remained in normal sinus rhythm after surgery. All 72 patients completed the study. Postoperative AF developed in 26 (36%) patients. Perioperative monocyte CD11b upregulation was significantly increased in patients who developed AF (P = 0.01), but increases in PMN CD11b were not significantly associated with AF (P = 0.057). The increase in both monocyte and PMN counts after aortic cross-clamp release was significantly associated with postoperative AF (P = 0.007 and P = 0.005, respectively). By contrast, preoperative CRP and perioperative MPO did not differ between AF and normal rhythm patients. Similarly, the peak value of troponin I did not differ between groups. In this pilot study of cardiac surgery/CPB patients, perioperative upregulation of the monocyte adhesion receptor, CD11b, and higher circulating monocyte and PMN numbers were associated with postoperative AF, suggesting that the induction of cellular inflammation during cardiac surgery/CPB may contribute to this pathophysiology.

Role of endogenous adenosine in atrial fibrillation after coronary artery bypass graft

BACKGROUND

Atrial fibrillation (AF) is the most common complication following coronary artery bypass graft (CABG). The mechanism of AF after CABG is not well defined; however, it is suggested that endogenous adenosine, released in response to tissue hypoxia, may play a mechanistic role in these arrhythmias.

HYPOTHESIS

The purpose of this study was to examine whether intravenous theophylline, via adenosine A1 receptor antagonism, would correct or modify new-onset early (<48 h post CABG) atrial fibrillation in patients post CABG, and thereby implicate endogenous adenosine as an inciting agent.

METHODS

A prospective double-blind, placebo-controlled study design was applied to 385 consecutive patients with coronary artery disease who had undergone CABG. Any patient who developed AF within 48 h of the operative procedure was randomly assigned to receive 5 mg/kg of intravenous theophylline (Group A) or matched intravenous placebo (Group B). The patients who converted to sinus rhythm within 15 min of drug administration were accepted as showing positive responses.

RESULTS

Thirty patients comprised the study group. In Group A, 8 of the 15 patients (53%) converted from AF to sinus rhythm within 15 min of theophylline administration. One patient who converted to sinus rhythm 20 min after theophylline administration was accepted as showing a negative response. In the placebo-treated group, no patient converted to sinus rhythm within 15 min (p<0.007 compared with Group A).

CONCLUSIONS

The mechanism of AF after CABG is not well defined and is probably multifactorial. However, this study demonstrated that antagonism of the adenosine A1 receptor can promptly convert many of these patients back to sinus rhythm, and thereby implicates endogenously released adenosine in a mechanistic role for inciting early (<48 h) post-CABG AF.

Preservation of the anterior fat pad paradoxically decreases the incidence of postoperative atrial fibrillation in humans

OBJECTIVES

The goal of this study was to determine if parasympathetic nerves in the anterior fat pad (FP) can be stimulated at the time of coronary artery bypass surgery (CABG), and if dissection of this FP decreases the incidence of postoperative atrial fibrillation (AF).

BACKGROUND

The human anterior epicardial FP contains parasympathetic ganglia and is often dissected during CABG. Changes in parasympathetic tone influence the incidence of AF.

METHODS

Fifty-five patients undergoing CABG were randomized to anterior FP preservation (group A) or dissection (group B). Nerve stimulation was applied to the FP before and after surgery. Sinus cycle length (CL) was measured during stimulation. The incidence of postoperative AF was recorded.

RESULTS

Of the 55 patients enrolled, 26 patients were randomized to group A, and 29 patients were randomized to group B. In all of the 55 patients, the FP was identified before initiating cardiopulmonary bypass by CL prolongation with stimulation (865.5 +/- 147.9 ms vs. 957.9 +/- 155.1 ms, baseline vs. stimulation, p < 0.001). In group A, stimulation at the conclusion of surgery increased sinus CL (801.8 +/- 166.4 ms vs. 890.9 +/- 178.2 ms, baseline vs. stimulation, p < 0.001). In group B, repeat stimulation failed to increase sinus CL (853.6 +/- 201.6 ms vs. 841.4 +/- 198.4 ms, baseline vs. stimulation, p = NS). The incidence of postoperative AF in group A (7%) was significantly less than that in group B (37%) (p < 0.01).

CONCLUSIONS

This is the first study demonstrating that direct stimulation of the human anterior epicardial FP slows sinus CL. This parasympathetic effect is eliminated with FP dissection. Preservation of the human anterior epicardial FP during CABG decreases incidence of postoperative AF.

Ventral cardiac denervation reduces the incidence of atrial fibrillation after coronary artery bypass grafting

OBJECTIVES

Because the autonomic nervous system is an important determinant in the appearance of atrial fibrillation, we have assessed the role of ventral cardiac denervation for its prevention.

METHODS

Patients undergoing low-risk coronary artery surgery were enrolled. No routine antiarrhythmic drugs were administered before or after the operation. Ventral cardiac denervation was performed in 207 patients, and 219 patients were used as control subjects. Denervation was performed before cardiopulmonary bypass. The groups were comparable regarding demographic, clinical, and operative variables.

RESULTS

The additional time for the denervation was 5 +/- 2 minutes, and there were no associated complications. Postoperative atrial fibrillation was present in 15 (7%) patients undergoing ventral cardiac denervation (95% confidence interval, 4%-12%) and in 56 (27%) control subjects (95% confidence interval, 18%-35%). Patients submitted to ventral cardiac denervation had fewer and less severe episodes of atrial fibrillation, and no patient had atrial fibrillation after discharge. Ventral cardiac denervation was the most significant predictor of postoperative atrial fibrillation (odds ratio, 0.42; confidence interval, 0.23-0.78; P =.006). Age of greater than 65 years (odds ratio, 1.67; confidence interval, 0.96-2.9; P =.067) was a highly suggestive predictor. The analysis of the effect of ventral cardiac denervation correlated with the patient's age showed a more pronounced effect in patients younger than 70 years (odds ratio, 0.43; confidence interval, 0.22-0.86; P =.022)

CONCLUSIONS

Ventral cardiac denervation is a fast and low-risk procedure. Its use significantly reduces the incidence and severity of atrial fibrillation after routine coronary artery bypass surgery. Patients younger than 70 years of age are expected to have a higher success rate than those older than 70 years.

Off-pump coronary artery bypass graft surgery: the incidence of postoperative atrial fibrillation

Atrial fibrillation (AF) occurs in one quarter to one third of patients after coronary artery bypass graft surgery (CABG). Conventional CABG uses cardiopulmonary bypass, a process that is itself associated with a systemic vascular inflammatory response that contributes to postoperative morbidity. The avoidance of cardiopulmonary bypass is associated with a significant reduction in the inflammatory response and in the release of markers of myocardial necrosis when compared with conventional CABG. There is speculation that off-pump CABG may reduce the incidence of postoperative AF through reduced trauma, ischaemia, and inflammation. Current data, however, do not emphatically answer the question of whether the incidence of post-CABG AF is reduced by off-pump surgery. The evidence from both observational and randomised studies is conflicting and many studies have weaknesses in design, conduct, or interpretation. It remains an attractive hypothesis that postoperative AF is reduced by off-pump CABG but more robust data are required.

No decrease in incidence of atrial fibrillation in patients undergoing off-pump coronary artery bypass grafting

BACKGROUND

With the introduction of beating heart surgery, there has been a renewed interest in the incidence of postoperative atrial fibrillation (AF) in patients undergoing coronary artery bypass grafting (CABG). A small number of studies have reported markedly decreased incidences of postoperative AF in patients undergoing off-pump CABG.

AIMS

The aim of the present study was to review the incidence of AF in patients undergoing off-pump CABG at Royal Melbourne Hospital.

METHODS

A retrospective review was undertaken of 80 patients who had elective first-time CABG off-pump over a 16-month period. These patients were matched with 80 patients who underwent CABG with cardiopulmonary bypass (CPB). Data on preoperative and operative variables were collected. Incidences of postoperative AF in both groups were recorded.

RESULTS

The incidence of AF in the off-pump group was 27 of 80 patients (34%) and in the CPB group it was 25 of 80 patients (31%; NS). Increasing age was a significant risk factor for developing postoperative AF, and beta-blockade was identified as a protective factor.

CONCLUSIONS

Off-pump CABG does not decrease the incidence of postoperative atrial fibrillation. A randomised prospective trial has been commenced at Royal Melbourne Hospital to further investigate postoperative outcomes of off-pump CABG.