A prospective randomized controlled trial on the incidence and predictors of late-phase postoperative atrial fibrillation up to 30 days and the preventive value of biatrial pacing

Epigenetic MicroRNAs as Prognostic Markers of Postoperative Atrial Fibrillation: A Systematic Review

Postoperative atrial fibrillation (POAF) is a common complication after cardiac surgery, increasing the risk for adverse outcomes such as perioperative and long-term mortality, stroke, myocardial infarction, and other thromboembolic events. Epigenetic biomarkers show promise as prognostic tools for POAF. Epigenetic changes, such as DNA methylation, histone modification, and microRNAs (miRNA), can result in altered gene expression and the development of various pathological conditions. This systematic review aims to present the current literature on the association between various epigenetic markers and the development of POAF following cardiac surgery. Here, an electronic literature search was performed using MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and Google Scholar to identify studies that reported the role of epigenetic markers in the development of POAF. Five of the 6 studies focused on miRNAs and their association with POAF. In POAF patients, the expression of miR-1 and miR-483-5p were upregulated in the right atrial appendage (RAA), while the levels of miR-133A, miR-208a, miR-23a, miR-26a, miR-29a, miR-29b, and miR-29c were decreased in the RAA and venous blood. One study examined cytosines followed by guanines (CpGs) as DNA methylation markers. Across all studies, 488 human subjects who had undergone cardiac surgery were investigated, and 195 subjects (39.9%) developed new-onset POAF. The current literature suggests that miRNAs may play a role in predicting the development of atrial fibrillation after cardiac surgery. However, more robust clinical data are required to justify their role in routine clinical practice.

Post-operative atrial fibrillation after cardiac surgery: Challenges throughout the patient journey

Atrial fibrillation (AF) is the most common complication of cardiac surgery, occurring in up to half of patients. Post-operative AF (POAF) refers to new-onset AF in a patient without a history of AF that occurs within the first 4 weeks after cardiac surgery. POAF is associated with short-term mortality and morbidity, but its long-term significance is unclear. This article reviews existing evidence and research challenges for the management of POAF in patients who have had cardiac surgery. Specific challenges are discussed in four phases of care. Pre-operatively, clinicians need to be able to identify high-risk patients, and initiate prophylaxis to prevent POAF. In hospital, when POAF is detected, clinicians need to manage symptoms, stabilize hemodynamics and prevent increases in length of stay. In the month after discharge, the focus is on minimizing symptoms and preventing readmission. Some patients require short term oral anticoagulation for stroke prevention. Over the long term (2-3  months after surgery and beyond), clinicians need to identify which patients with POAF have paroxysmal or persistent AF and can benefit from evidence-based therapies for AF, including long-term oral anticoagulation.

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

BACKGROUND

Postoperative atrial fibrillation (POAF) is a frequent complication after heart surgery and is associated with thromboembolic events, prolonged hospital stay, and adverse outcomes. Inflammation and fibrosis are involved in the pathogenesis of atrial fibrillation.

OBJECTIVE

The purpose of this study was to assess whether galectin-3, which reflects preexisting atrial fibrosis, has the potential to predict POAF and mortality after cardiac surgery.

METHODS

Four hundred seventy-five consecutive patients (mean age 67.4 ± 11.8 years; 336 (70.7%) male) undergoing elective heart surgery at the Medical University of Vienna were included in this prospective single-center cohort study. Galectin-3 plasma levels were assessed on the day before surgery.

RESULTS

The 200 patients (42.1%) who developed POAF had significantly higher galectin-3 levels (9.60 ± 6.83 ng/mL vs 7.10 ± 3.54 ng/mL; P < .001). Galectin-3 significantly predicted POAF in multivariable logistic regression analysis (adjusted odds ratio per 1-SD increase 1.44; 95% confidence interval 1.15-1.81; P = .002). During a median follow-up of 4.3 years (interquartile range 3.4-5.4 years), 72 patients (15.2%) died. Galectin-3 predicted all-cause mortality in multivariable Cox regression analysis (adjusted hazard ratio per 1-SD increase 1.56; 95% confidence interval 1.16-2.09; P = .003). Patients with the highest-risk galectin-3 levels according to classification and regression tree analysis (>11.70 ng/mL) had a 3.3-fold higher risk of developing POAF and a 4.4-fold higher risk of dying than did patients with the lowest-risk levels (≤5.82 ng/mL).

CONCLUSION

The profibrotic biomarker galectin-3 is an independent predictor of POAF and mortality after cardiac surgery. This finding highlights the role of the underlying arrhythmogenic substrate in the genesis of POAF. Galectin-3 may help to identify patients at risk of POAF and adverse outcome after cardiac surgery.

The Influence of Multivessel Bypass Surgery on the Onset of Atrial Fibrillation in Elderly Patients

Aim. To study the factors associated with the development of postoperative atrial fibrillation (POAF) with single- or two- or more vascular bypass grafting in elderly patients with coronary heart disease.Methods. The study included 454 patients with coronary artery disease who underwent CABG. Patients were divided into 4 groups: 1 group – with single-vessel bypass, 2 group – with 2-vessels, 3 group – with 3-vessels and 4 group with 4-vessels bypass. During the observation period postoperative atrial fibrillation (POAF) occurred in 7.5% of patients in group 1, 18.4% in group 2, 17.5% in group 3 and 19.2% of patients in group 4. Since there were no significant differences in the incidence of POAF in patients with 2-4-vessels bypass grafting, these groups were combined for further analysis. 2 groups are allocated: Group I comprised patients with single-vessel bypass graft (79 patients, 76.0% of males, the average age of 65.0 [63.0;68.0] years), Group II – with 2-4-vessels bypass grafts (357 patients, 78.4% of males, the median age of 67.5 [64.5;69.0] years).Results. POAF occurred in 7.5% of patients in group I and in 18.4% of patients in group II (p=0.03) on the median 4.9 [1.2;8.7] day after coronary artery bypass graft. The multivariate regression analysis showed that indicators, associated with POAF development in patients undergoing CABG were the following: aortic cross-clamping time >36 min (odds ratio [OR)]1.4; 95% confidence interval (CI) 1.1-2.8; p=0.030), time of ischemia >19 min (OR 1.7; 95% CI 1.2-3.3; p=0.020), age >65 years (OR 1.8; 95% CI 1,1-4,1; p=0.010), left atrium diameter >39 mm (OR 2.9; 95% CI 1.5-5.4; p=0.005), left ventricular ejection fraction <51% (OR 1.9; 95% CI 1.2-3.0; p=0.04).Conclusion. In our study, atrial fibrillation in the early postoperative period was more common in patients undergoing multivessel coronary bypass surgery. Indicators, significantly associated with POAF in patients undergoing Coronary artery bypass graft were aortic cross-clamping time >36 minutes, time of ischemia >19 minutes, age >65 years, left atrium diameter >39 mm and left ventricular ejection fraction <51%.

Postoperative atrial fibrillation and atrial epicardial fat: Is there a link?

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Detailed local EAT analysis does not differ between POAF and non-POAF.

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General rather than local effects of EAT play a role in the onset of early POAF.

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The dominance of surgical induced factors may obscure the potential role of EAT.

Background

Atrial Epicardial Adipose Tissue (EAT) is presumably involved in the pathogenesis of atrial fibrillation (AF). The transient nature of postoperative AF (POAF) suggests that surgery-induced triggers provoke an unmasking of a pre-existent AF substrate. The aim is to investigate the association between the volume of EAT and the occurrence of POAF. We hypothesise that the likelihood of developing POAF is higher in patients with high compared to low left atrial (LA) EAT volumes.

Methods

Quantification of LA EAT based on the Hounsfield Units using custom made software was performed on pre-operative coronary computed tomography angiography scans of patients who underwent cardiac surgery between 2009 and 2019. Patients with mitral valve disease were excluded.

Results

A total of 83 patients were included in this study (CABG = 34, aortic valve = 33, aorta ascendens n = 7, combination n = 9), of which 43 patients developed POAF. The EAT percentage in the LA wall nor indexed EAT volumes differed between patients with POAF and with sinus rhythm (all P > 0.05). In multivariable analysis, age and LA volume index (LAVI) were the only independent predictors for early POAF (OR: 1.076 and 1.056, respectively).

Conclusions

As expected, advanced age and LAVI were independent predictors of POAF. However, the amount of local EAT was not associated with the occurrence of AF after cardiac surgery. This suggests that the role of EAT in POAF is rather limited, or that the association of EAT in the early phase of POAF is obscured by the dominance of surgical-induced triggers.

Dose-response relationship among body mass index, abdominal adiposity and atrial fibrillation in patients undergoing cardiac surgery: a meta-analysis of 35 cohorts

Background

Whether overweight increases the risk of postoperative atrial fibrillation (POAF) is unclear, and whether adiposity independently contributes to POAF has not been comprehensively studied. Thus, we conducted a meta-analysis to clarify the strength and shape of the exposure-effect relationship between adiposity and POAF.

Methods

The PubMed, Cochrane Library, and EMBASE databases were searched for revelant studies (randomized controlled trials (RCTs), cohort studies, and nest-case control studies) reporting data regarding the relationship between adiposity and the risk of POAF.

Results

Thirty-five publications involving 33,271 cases/141,442 patients were included. Analysis of categorical variables showed that obesity (RR: 1.39, 95% CI [1.21–1.61]; P < 0.001), but not being underweight (RR: 1.44, 95% CI [0.90–2.30]; P = 0.13) or being overweight (RR: 1.03, 95% CI [0.95–1.11]; P = 0.48) was associated with an increased risk of POAF. In the exposure-effect analysis (BMI) was 1.09 (95% CI [1.05–1.12]; P < 0.001) for the risk of POAF. There was a significant linear relationship between BMI and POAF (P_nonlinearity = 0.44); the curve was flat and began to rise steeply at a BMI of approximately 30. Notably, BMI levels below 30 (overweight) were not associated with a higher risk of POAF. Additionally, waist obesity or visceral adiposity index was associated with the risk of POAF.

Conclusion

Based on the current evidence, our findings showed that high body mass index or abdominal adiposity was independently associated with an increased risk of POAF, while underweight or overweight might not significantly increase the POAF risk.

Clinical and electrophysiological predictors of device-detected new-onset atrial fibrillation during 3 years after cardiac surgery

Aims

Postoperative atrial fibrillation (POAF) after cardiac surgery is an independent predictor of stroke and mortality late after discharge. We aimed to determine the burden and predictors of early (up to 5th postoperative day) and late (after 5th postoperative day) new-onset atrial fibrillation (AF) using implantable loop recorders (ILRs) in patients undergoing open chest cardiac surgery.

Methods and results

Seventy-nine patients without a history of AF undergoing cardiac surgery underwent peri-operative high-resolution mapping of electrically induced AF and were followed 36 months after surgery using an ILR (Reveal XT™). Clinical and electrophysiological predictors of late POAF were assessed. POAF occurred in 46 patients (58%), with early POAF detected in 27 (34%) and late POAF in 37 patients (47%). Late POAF episodes were short-lasting (mostly between 2 min and 6 h) and showed a circadian rhythm pattern with a peak of episode initiation during daytime. In POAF patients, electrically induced AF showed more complex propagation patterns than in patients without POAF. Early POAF, right atrial (RA) volume, prolonged PR time, and advanced age were independent predictors of late POAF.

Conclusions

Late POAF occurred in 47% of patients without a history of AF. Patients who develop early POAF, with higher age, larger RA, or prolonged PR time have a higher risk of developing late POAF and may benefit from intensified rhythm follow-up after cardiac surgery.

Clinicaltrials.gov number

NCT01530750.

The contribution of intermittent handheld electrocardiogram and continuous electrocardiogram monitoring with an implantable loop recorder to detect incident and recurrent atrial fibrillation during 1 year after coronary artery bypass graft surgery: A prospective cohort study

Background

Atrial fibrillation (AF) is common after coronary artery bypass graft (CABG) surgery.

Objective

To evaluate the incidence and recurrence rate of AF during 1 year after CABG surgery. We also aimed at calculating the AF burden and compare long-term intermittent vs continuous electrocardiogram (ECG) monitoring.

Methods

Forty patients scheduled for CABG surgery were equipped with an implantable loop recorder (ILR). After discharge, they carried out handheld ECG 3 times daily during the first 30 postoperative days and during 2 weeks at 3 and 12 months. During hospital stay they were monitored with telemetry.

Results

Altogether 27 of 40 (68%) patients were diagnosed with AF, 24 during the first month (21 in-hospital and 3 after discharge) and 3 during months 2–12. Three patients progressed into persistent AF. In addition, 17 patients had AF recurrence, 9 of them after the first 30 days. In patients with paroxysmal AF, the AF burden was low, 0.1% (interquartile range [IQR] 0.02%–0.3%). Patients with AF had higher CHA₂DS₂-VASc scores than non-AF patients: median 4 (IQR 3–4) and 3 (IQR 2–3.5), respectively, P = .006. The handheld ECG identified 45% (9/20) of the patients with AF episodes identified with continuous ECG monitoring with the ILR after discharge from hospital, P = .001.

Conclusions

Patients with AF during the postoperative hospitalization showed a high likelihood of recurrent AF, usually within 30 days. Continuous ECG monitoring with an ILR was superior to the handheld ECG for detecting patients with AF. The AF burden was low.

The impact of volume substitution on post-operative atrial fibrillation

BACKGROUND

Post-operative atrial fibrillation (POAF) represents a common complication after cardiac valve or coronary artery bypass surgery. While strain of atrial tissue is known to induce atrial fibrillating impulses, less attention has been paid to potentially strain-promoting values during the peri- and post-operative period. This study aimed to determine the association of peri- and post-operative volume substitution with markers of cardiac strain and subsequently the impact on POAF development and promotion.

RESULTS

A total of 123 (45.4%) individuals were found to develop POAF. Fluid balance within the first 24 hours after surgery was significantly higher in patients developing POAF as compared to non-POAF individuals (+1129.6 mL [POAF] vs +544.9 mL [non-POAF], P = .044). Post-operative fluid balance showed a direct and significant correlation with post-operative N-terminal pro-brain natriuretic peptide (NT-ProBNP) values (r = .287; P = .002). Of note, the amount of substituted volume significantly proved to be a strong and independent predictor for POAF with an adjusted odds ratio per one litre of 1.44 (95% CI: 1.09-1.31; P = .009). In addition, we observed that low pre-operative haemoglobin levels at admission were associated with a higher need of intraoperative transfusions and volume-demand.

CONCLUSION

Substitution of larger transfusion volumes presents a strong and independent predictor for the development of POAF. Via the observed distinct association with NT-proBNP values, it can reasonably be assumed that post-operative atrial fibrillating impulses are triggered via increased global cardiac strain. Optimized pre-operative management of pre-existing anaemia should be considered prior surgical intervention in terms of a personalized patient care.

Reappraisal of Atrial fibrillation: interaction between hyperCoagulability, Electrical remodelling and Vascular destabilisation in the progression of AF (RACE V) Tissue Bank Project: study design

Background

The development of atrial fibrillation (AF) is a complex multifactorial process. Over the past few decades, much has been learned about the pathophysiological processes that can lead to AF from a variety of specific disease models in animals. However, our ability to recognise these disease processes in AF patients is still limited, which has contributed to the limited progress in improving rhythm control in AF.

Aims/objectives

We believe that a better understanding and detection of the individual pathophysiological mechanisms underlying AF is a prerequisite for developing patient-tailored therapies. The RACE V Tissue Bank Project will contribute to the unravelling of the main molecular mechanisms of AF by studying histology and genome-wide RNA expression profiles and combining this information with detailed phenotyping of patients undergoing cardiac surgery.

Methods

As more and more evidence suggests that AF may occur not only during the first days but also during the months and years after surgery, we will systematically study the incidence of AF during the first years after cardiac surgery in patients with or without a history of AF. Both the overall AF burden as well as the pattern of AF episodes will be studied. Lastly, we will study the association between the major molecular mechanisms and the clinical presentation of the patients, including the incidence and pattern of AF during the follow-up period.

Conclusion

The RACE V Tissue Bank Project combines deep phenotyping of patients undergoing cardiac surgery, including rhythm follow-up, analysis of molecular mechanisms, histological analysis and genome-wide RNA sequencing. This approach will provide detailed insights into the main pathological alterations associated with AF in atrial tissue and thereby contribute to the development of individualised, mechanistically informed patient-tailored treatment for AF.

Predictors of postoperative atrial fibrillation persisting beyond hospital discharge after coronary artery bypass grafting

OBJECTIVE

Minimal invasive extracorporeal circuits (MiECC) have been associated with a significant reduction in the incidence of postoperative atrial fibrillation (AF). Nevertheless, AF remains one of the most common complications following elective primary coronary artery bypass grafting (CABG). The aim of this study was to identify the predictors of AF persisting beyond the hospital stay in elective primary CABG patients.

METHODS

We conducted a retrospective analysis for the predictors of AF that persisted beyond discharge between all patients who received an elective isolated CABG in our institution between 2009 and 2014. Patients with a positive history for intermittent or persistent AF were excluded from the analysis. Almost all patients were discharged to a rehabilitation facility where they stayed for 3 to 4 weeks postoperatively. At rehab approximately 91% of them received Holter monitoring at least once prior to their discharge.

RESULTS

A total of 770 patients were included in the analysis of which 763 patients survived the in-hospital stay. The incidence of AF at hospital discharge was 4.2% (32/763) while that on Holter monitor at Rehab was 1.5% (10/685). Age and the type of extracorporeal circuit (ECC) utilized were the only significant predictors for both AF at discharge (p < 0.01 both) and on Holter monitor in rehab (p < 0.01 and 0.02, respectively). This was also confirmed on multivariate analysis.

CONCLUSION

Our findings show that the benefits of MiECC regarding the incidence of postoperative AF persist beyond hospital discharge. They may thus positively influence the outcomes of patients beyond the early postoperative period.

Temporal Dispersion of Atrial Activation Causes Postoperative Atrial Fibrillation

BACKGROUND

Spatial dispersion of atrial activation is a cause of postoperative atrial fibrillation (PoAF) after cardiac surgery. This study evaluated whether temporal dispersion of atrial activation causes PoAF after surgery in a clinical setting.

METHODS

Nineteen patients were enrolled. Postoperative atrial activation was evaluated by 24-hour Holter electrocardiography, with atrial pacing wires on the right atrium, for 5 days after cardiac surgery. No patient received antiarrhythmic drugs, including beta-blockers. The cycle length of 15 continuous atrial beats was measured at 4 time points: (i) earlier than 12 hours before PoAF, as a control, (ii) just before PoAF onset, (iii) during PoAF, and (iv) just before cessation of PoAF. Inhomogeneity of atrial activation was quantified by using the variation coefficient for a cycle length of 15 atrial beats during each phase.

RESULTS

The median inhomogeneity index of atrial activation (interquartile range) was 0.102 (0.046-0.136) in controls, 0.943 (0.582-1.610) just before PoAF onset (vs. control; p=0.009), 0.966 (0.631-1.117) during PoAF, and 0.471 (0.138-0.645) just before cessation of PoAF.

CONCLUSIONS

Dispersion of atrial activation significantly increased just before PoAF onset. Temporal dispersion of atrial activation is a precursory variation of PoAF.

What Influences the Patients with Left Atrial Myxoma: From Embolism to Postoperative Atrial Fibrillation

BACKGROUND

Preoperative embolism and postoperative atrial fibrillation (POAF) are two important factors associated with impaired health conditions and increased economic burden in patients with left atrial (LA) myxoma. The aim of this study was to analyze embolic events, identify predictors of POAF, and evaluate the risk of late-term survival in patients with LA myxoma.

METHODS

From December 2009 to December 2019, 177 consecutive patients with LA myxoma who met the selection criteria were included in the retrospective analysis. Multivariate logistic regression analysis was performed to identify predictors of POAF. Propensity score matching was used for confounder control, and Cox proportional hazards models were used to evaluate the risk of late-term mortality.

RESULTS

The study population comprised of 125 patients in non-POAF group and 52 patients in POAF group. Preoperative embolism was present in 27.1% of the all cases. By multivariate analysis, age, NYHA functional class III, LA diameter, and cross-clamp time were identified as independent predictors of in-hospital POAF. The overall survival at 1, 5, and 10 years for the 177 patients was 98.9%, 93.7%, and 84.4%, respectively. There was no statistical difference in late-term survival between the two groups in the Cox proportion-adjusted survival curve. After propensity score 1:1 matching, patients with POAF had a longer postoperative hospital stay and Kaplan-Meier survival curve also showed no statistical difference between the two groups.

CONCLUSIONS

Patients with LA myxoma after surgical treatment had a favorable prognosis. In-hospital POAF was not independently associated with late-term mortality in patients with LA myxoma.

Postoperative Atrial Fibrillation Following Cardiac Surgery: From Pathogenesis to Potential Therapies

Postoperative atrial fibrillation (POAF) is a major complication after cardiac surgery which can lead to high rates of morbidity and mortality, an enhanced length of hospital stay, and an increased cost of care. POAF is postulated to be a multifactorial phenomenon; however, some major pathogeneses have been proposed, including inflammatory pathways, oxidative stress, and autonomic dysfunction. Genetic studies also showed that inflammatory pathways, beta-1 adrenoreceptor variants, G protein-coupled receptor kinase 5 gene variants, and non-coding single-nucleotide polymorphisms in the 4q25 chromosomal locus are involved in this phenomenon. Moreover, several predisposing factors lead to the development of POAF, consisting of pre-, intra-, and postoperative contributors. The main predisposing factors comprise age, prior history of major cardiovascular risk factors, and ischemia-reperfusion injury during surgery. The management of POAF is based on the usual therapies used for non-surgical AF, including medications for either rate control or rhythm control in hemodynamically unstable patients. The perioperative administration of β-blockers and some antiarrhythmic agents has been recommended in major international guidelines. In addition, upstream therapies consisting of colchicine, magnesium, statins, and antioxidants have attenuated the incidence of POAF; however, some uncomfortable side effects developed in large randomized trials. The use of anticoagulation has also resulted in less mortality in patients with POAF at higher risk of thromboembolic events. Despite these recommendations, the actual regimen for the prevention of POAF remains controversial. In this review, we highlight the pathogenesis, predisposing factors, and potential therapeutic options for the management of patients at risk for or with POAF following cardiac surgery.

Incidence of postoperative atrial fibrillation recurrence in patients discharged in sinus rhythm after cardiac surgery: a systematic review and meta-analysis

Postoperative atrial fibrillation (POAF) is associated with increased stroke risk and mortality post-discharge. POAF is often considered transient; however, recurrence is likely under-recognized as symptoms are an unreliable guide. Surveillance post-discharge may identify asymptomatic POAF recurrences in patients discharged in sinus rhythm. Therefore, we performed a systematic review and meta-analysis of studies investigating POAF recurrence post-discharge, in patients with new-onset POAF following cardiac surgery who reverted to sinus rhythm prior to discharge. Two independent reviewers searched medical databases, clinical trial registries, reference lists and the Internet. After screening from 6525 studies, 8 studies were identified (n = 1157 participants, mean age 66 ± 10 years and 73% men). Monitoring methods included the following: telemetry during twice-daily exercise sessions (n = 2), continuous telemetry for 3 weeks (n = 1), daily 20-s electrocardiography (ECG) using wearable event recorder (n = 1), 30-s single-lead ECG, 4 times/day (n = 1) and implanted continuous monitoring (n = 2). The incidence rate of POAF recurrence identified through non-invasive monitoring in the first 4 weeks post-discharge was 28.3% [confidence interval (CI) 23.0-33.6%]; recurring 12 ± 5 days (mean ± SD) post-surgery. The incidence rate identified through implanted continuous monitoring was 61-100% within 2 years. Between 40% and 93% of episodes were asymptomatic. In one small study reporting stroke risk, 8 of 10 patients with recurrence were guideline-indicated (CHA2DS2-VASc score ≥2) for oral anticoagulation for stroke prevention. Monitoring for POAF recurrence post-hospital discharge identifies significant numbers of early asymptomatic recurrences in patients at high risk of stroke who may benefit from anticoagulation for stroke prevention. More intense monitoring is more likely to identify POAF recurrence. Future research is required to investigate the prognostic significance of POAF recurrence, especially stroke and mortality risk.

Temporary autonomic modulation with botulinum toxin type A to reduce atrial fibrillation after cardiac surgery

BACKGROUND

Postoperative atrial fibrillation (POAF) frequently complicates cardiac surgery and is associated with worse outcomes. The cardiac autonomic nervous system is implicated in the pathogenesis of POAF.

OBJECTIVE

The purpose of this study was to determine the efficacy and safety of selective cardiac autonomic modulation in preventing POAF.

METHODS

In this randomized, double-blind, placebo-controlled trial, adults undergoing cardiac surgery were randomized 1:1 to intraoperative injection of 250 units onabotulinumtoxinA (botulinum toxin type A [BoNTA]) or placebo into epicardial fat pads. The study was powered to detect a 40% reduction in relative risk of POAF. Time to first episode of in-hospital POAF was the primary outcome, evaluated in patients receiving injection. Additionally, incidence of POAF, length of stay (LOS), and adverse events were examined.

RESULTS

The trial assigned 145 patients to injection, 15 of whom were dropped before treatment, leaving 130 patients for analysis. Overall, 36.5% (23/63) of BoNTA-treated patients developed POAF compared with 47.8% (32/67) of placebo-treated patients. The time-to-event analysis revealed a hazard ratio of 0.69 (95% confidence interval 0.41-1.19; P = .18) for the BoNTA vs placebo arm. There were no significant differences in postoperative hospital LOS (median [interquartile range] 6.0 [3.4] vs 6.2 [3.7] days; P = .51) or adverse events prolonging LOS (27/63 [42.9%] vs 30/67 [44.8%]; P = .83) in patients receiving BoNTA vs placebo.

CONCLUSION

Epicardial injection of onabotulinumtoxinA was without discernible adverse effects, but we failed to detect a significant difference in risk of POAF. Future large-scale studies of epicardial onabotulinumtoxinA injection as a potential POAF prevention strategy should be designed to study smaller, but clinically meaningful, treatment effects.

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.

Incidence and predictors of atrial fibrillation after coronary artery bypass surgery: detection by event loop recorder monitoring from a contemporary multicentre cohort

Background Atrial fibrillation (AF) is a frequent complication after cardiac surgery. We explored the incidence and predictors of post-operative AF at 30-day follow-up in an unselected multi-centre cohort of patients undergoing elective coronary artery bypass grafting (CABG) in contemporary practice. Methods and results We enrolled 740 consecutive patients scheduled for elective CABG with or without valve surgery. Cardiac rhythm was continuously monitored for 15 days after surgery by an ambulatory event loop recorder. Clinical follow-up for the occurrence of arrhythmias was performed for the next 15 days by office visits. The primary end point was the incidence of AF at 30-day follow-up. Mean age was 56.5 ± 8.9 years; 69.5% were males; 80% had diabetes. All patients completed 30-day follow-up. At the end of 30 days, AF occurred in 77 patients (10.4%). Most episodes (47 out of 77 episodes, 61%) of AF occurred during post-operative day 2. Episodes of AF were very rare after the first 5 post-operative days (3 out of 77 episodes, 3.9%). Multivariable regression analysis identified the following independent predictors of AF at 30-day follow-up: the lack of beta blocker use (hazard ratio 0.37, 95% confidence interval 0.21-0.64, P < 0.001), and the preoperative left atrial volume index (hazard Ratio 2.21, 95% confidence interval 1.79-2.74, P < 0.001). Conclusions In patients undergoing elective CABG, the incidence of post-operative AF at 30-day follow-up is rather low; the lack of beta blocker use in the perioperative period, and the preoperative left atrial volume index independently predicted the occurrence of AF at 30 days.

Management of Patients with Atrial Fibrillation: Focus on Treatment Options

Atrial fibrillation (AF) is leading cardiac arrhythmia with important clinical implications. Its diagnosis is usually made on the basis on 12-lead ECG or 24-hour Holter monitoring. More and more clinical evidence supports diagnostic use of cardiac event recorders and cardiovascular implantable electronic devices (CIED). Treatment options in patients with atrial fibrillation are extensive and are based on chosen rhythm and/or rate control strategy. The use and selected contraindications to AF related pharmacotherapy, including anticoagulants are shown. Nonpharmacological treatments, comorbidities and risk factors control remain mainstay in the treatment of patients with AF. Electrical cardioversion consists important choice in rhythm control strategy. Much progress has been made in the field of catheter ablation and cardiac surgery methods. Left atrial appendage occlusion/closure may be beneficial in patients with AF. CIED are used with clinical benefits in both, rhythm and rate control. Pacemakers, implantable cardioverter-defibrillators and cardiac resynchronization therapy devices with different pacing modes have guaranteed place in the treatment of patients with AF. On the other hand, the concepts of permanent leadless cardiac pacing, atrial dyssynchrony syndrome treatment and His-bundle or para-Hisian pacing have been proposed. This review summarizes and discusses current and novel treatment options in patients with atrial fibrillation.

Preoperative Hemoglobin A1c and the Occurrence of Atrial Fibrillation Following On-pump Coronary Artery Bypass Surgery in Type-2 Diabetic Patients

BACKGROUND

We investigated the association of the preoperative hemoglobin A1c (HbA1c) with occurrence of postoperative atrial fibrillation (POAF) in type-2 diabetic patients who underwent isolated coronary artery bypass grafting.

METHODS

We prospectively studied 708 type-2 diabetes patients [433 men ([61.2%)], candidate for isolated coronary artery bypass grafting. Biochemistry profile was measured on the day of operation. All patients were telemonitored for 72 hours after operation for the occurrence of atrial fibrillation. The role of HbA1c as a predictor for the occurrence of atrial fibrillation was then evaluated.

RESULTS

A total of 109 (15.3%) patients developed POAF. Patients in the atrial fibrillation group tended to be older, with prolonged longer diabetes, and have renal failure, chronic obstructive pulmonary disease, and hypertension. In the univariable and multivariable regression model, HbA1c was not a predictor for POAF.

CONCLUSIONS

Serum level of HbA1c could not be used as a predictor for the development of POAF.

Management of postoperative atrial fibrillation in cardiac surgery patients

Postoperative atrial fibrillation (AF) is a common arrhythmia following cardiac surgery and contributes to patient morbidity, prolonged hospital stay, and increased financial costs. The risk of postoperative AF may increase based on patient characteristics or events that occur intraoperatively or postoperatively. An understanding of these risks may be helpful in identifying which patients would benefit from prevention strategies. Acute AF presentation may range from completely indolent to rapidly progressing hemodynamic instability. Patients without hemodynamic compromise can be managed conservatively with rate control or initiation of antiarrhythmic medications. Patients with significant hemodynamic instability should undergo direct current cardioversion. In the postoperative period, it is reasonable to initiate anticoagulation after 48 hours of sustained AF or frequent episodes of postoperative AF.

Early outcomes after isolated aortic valve replacement with rapid deployment aortic valve

OBJECTIVE

Minimal access aortic valve replacement is associated with favorable clinical outcomes; however, several meta-analyses have reported significantly longer crossclamp times compared with a full sternotomy. We examined the procedural and early safety outcomes after isolated rapid deployment aortic valve replacement by surgical approach in patients enrolled in the Surgical Treatment of Aortic Stenosis With a Next Generation Surgical Aortic Valve trial.

METHODS

The Surgical Treatment of Aortic Stenosis With a Next Generation Surgical Aortic Valve trial was a prospective, multicenter, single-arm study, with successful implants in 287 patients with aortic valve stenosis who underwent rapid deployment aortic valve replacement using the EDWARDS INTUITY Valve System (Edwards Lifesciences, Irvine, Calif). Patients were evaluated perioperatively for procedural times and technical success rates; at discharge, for hospital length of stay; and, at 30 days, for early adverse events.

RESULTS

A total of 158 patients underwent isolated aortic valve replacement through a full sternotomy (n = 71), upper hemisternotomy (n = 77), or right anterior thoracotomy (n = 10). Mean age at baseline was 75.7 ± 7.2 years. Mean aortic crossclamp and cardiopulmonary bypass times (minutes) were similar for full sternotomy and upper hemisternotomy, 43.5 ± 32.5/71.6 ± 41.8 and 43.1 ± 13.1/69.6 ± 19.1, respectively, and significantly longer for right anterior thoracotomy, 88.3 ± 18.6/122.2 ± 22.1 (P < .000). Early adverse event rates were similar, and in-hospital mortality rates were low regardless of surgical approach.

CONCLUSIONS

These data suggest that isolated rapid deployment aortic valve replacement through an upper hemisternotomy can lead to shorter crossclamp times than has been reported historically in the literature. This may facilitate minimal access aortic valve replacement by eliminating the issue of prolonged crossclamp times. Further, low in-hospital mortality and new permanent pacemaker implant rates were observed regardless of surgical approach.

Incidence and Predictors of New-Onset Silent Atrial Fibrillation after Coronary Artery Bypass Graft Surgery

AIMS

We investigated the incidence, risk factors, and prognostic impact of silent atrial fibrillation (AF) after coronary artery bypass graft (CABG) surgery.

METHODS

This observational study prospectively included 100 patients referred for CABG surgery. Holter ECG monitoring was used to record every arrhythmic event for 7 days. AF was defined as at least one episode >30 s. Episodes recorded on Holter ECG monitoring but not clinically identified were classified as silent AF.

RESULTS

Among 34 patients who developed new-onset AF, 13 had silent AF. Compared with patients with maintained sinus rhythm (SR), silent AF patients had a significantly higher logistic EuroSCORE (2.9 (1.5-5.2) versus 2.3 (1.4-3.7), p = 0.017) and were more likely to have previous sleep apnea (31% versus 8%, p = 0.016) and left atrial diameter >45 mm (36% versus 5%, p = 0.002). At one-year follow-up, 30% of silent AF patients had developed symptomatic AF versus 7% in the SR group (p = 0.03) and 11% in the clinical AF group (p = 0.21).

CONCLUSION

After CABG surgery, silent AF is common and may be associated with a higher incidence of recurrences at one-year follow-up than clinical AF. Improved screening for silent AF may help to reduce thromboembolic events in this high-risk population.