Postoperative Atrial Fibrillation

A Systematic Review of Ongoing Registered Research Studies on Post-Operative Atrial Fibrillation after Cardiac Surgery

Background/Objectives: New-onset atrial fibrillation (AF) after cardiac surgery is associated with patient-important outcomes. Uncertainty persists regarding its prevention, detection, and management. This review seeks to identify, compile, and describe ongoing registered research studies involving patients with or at risk for post-operative AF (POAF) after cardiac surgery. Methods: We searched clinical trial registries in January 2023 for studies focusing on POAF prediction, prevention, detection, or management. We extracted data from each record and performed descriptive analyses. Results: In total, 121 studies met the eligibility criteria, including 82 randomized trials. Prevention studies are the most common (n = 77, 63.6%), followed by prediction (n = 21, 17.4%), management (n = 16, 13.2%), and detection studies (n = 7, 5.8%). POAF after cardiac surgery is an area of active research. Conclusions: There are many ongoing randomized prevention studies. However, two major clinical gaps persist; future randomized trials should compare rate and rhythm control in patients who develop POAF, and long-term follow-up studies should investigate strategies to monitor for AF recurrence in patients with POAF.

Characterization of atrial arrhythmias following mitral valve repair: Incidence and risk factors

OBJECTIVES

This study aims to investigate the occurrence, type and correlation of early and late atrial arrhythmias following mitral valve repair in patients with no preoperative history of atrial arrhythmias.

METHODS

Patients undergoing mitral valve (MV) repair for degenerative disease were included. Early and late postoperative electrocardiograms were evaluated for the incidence and type of atrial arrhythmia (atrial fibrillation [AF] or atrial tachycardia [AT]).

RESULTS

The 192 patients were included. Early atrial arrhythmias occurred in 100/192 (52.1%) patients; AF in 61 (31.8%) patients, early AT in 15 (7.8%) and both in 24 (12.5%). In total 89% of patients were discharged in sinus rhythm. During a follow-up time of 7.3 years, 14 patients (7.3%) died and 49 (25.5%) patients developed late atrial arrhythmias. At 10 years, the cumulative incidence of any late atrial arrhythmia, with death as competing risk, was 64% (95% confidence interval [CI] = 55%-72%). On Fine-Gray model analysis, only early postoperative AF lasting >24 h was related to the development of late AF (hazard ratio 5.99, 95% CI = 1.78%-20.10%, p = .004). Early postoperative ATs were related to the development of late tachycardias, independent of their duration (<24 h hazard ratio 4.25, 95% CI = 1.89-9.57, p = .001 and >24 h hazard ratio 3.51, 95% CI = 1.65-7.46, p = .001).

CONCLUSIONS

Early and late atrial arrhythmias were common after MV repair surgery. Only early postoperative AF lasting >24 h was a risk factor for the occurrence of late AF. Conversely, any postoperative AT was correlated to the development of late ATs.

Intraoperative Oxygen Treatment, Oxidative Stress, and Organ Injury Following Cardiac Surgery: A Randomized Clinical Trial

Importance

Liberal oxygen (hyperoxia) is commonly administered to patients during surgery, and oxygenation is known to impact mechanisms of perioperative organ injury.

Objective

To evaluate the effect of intraoperative hyperoxia compared to maintaining normoxia on oxidative stress, kidney injury, and other organ dysfunctions after cardiac surgery.

Design, Setting, and Participants

This was a participant- and assessor-blinded, randomized clinical trial conducted from April 2016 to October 2020 with 1 year of follow-up at a single tertiary care medical center. Adult patients (>18 years) presenting for elective open cardiac surgery without preoperative oxygen requirement, acute coronary syndrome, carotid stenosis, or dialysis were included. Of 3919 patients assessed, 2501 were considered eligible and 213 provided consent. Of these, 12 were excluded prior to randomization and 1 following randomization whose surgery was cancelled, leaving 100 participants in each group.

Interventions

Participants were randomly assigned to hyperoxia (1.00 fraction of inspired oxygen [FiO2]) or normoxia (minimum FiO2 to maintain oxygen saturation 95%-97%) throughout surgery.

Main Outcomes and Measures

Participants were assessed for oxidative stress by measuring F2-isoprostanes and isofurans, for acute kidney injury (AKI), and for delirium, myocardial injury, atrial fibrillation, and additional secondary outcomes. Participants were monitored for 1 year following surgery.

Results

Two hundred participants were studied (median [IQR] age, 66 [59-72] years; 140 male and 60 female; 82 [41.0%] with diabetes). F2-isoprostanes and isofurans (primary mechanistic end point) increased on average throughout surgery, from a median (IQR) of 73.3 (53.1-101.1) pg/mL at baseline to a peak of 85.5 (64.0-109.8) pg/mL at admission to the intensive care unit and were 9.2 pg/mL (95% CI, 1.0-17.4; P = .03) higher during surgery in patients assigned to hyperoxia. Median (IQR) change in serum creatinine (primary clinical end point) from baseline to postoperative day 2 was 0.01 mg/dL (-0.12 to 0.19) in participants assigned hyperoxia and -0.01 mg/dL (-0.16 to 0.19) in those assigned normoxia (median difference, 0.03; 95% CI, -0.04 to 0.10; P = .45). AKI occurred in 21 participants (21%) in each group. Intraoperative oxygen treatment did not affect additional acute organ injuries, safety events, or kidney, neuropsychological, and functional outcomes at 1 year.

Conclusions

Among adults receiving cardiac surgery, intraoperative hyperoxia increased intraoperative oxidative stress compared to normoxia but did not affect kidney injury or additional measurements of organ injury including delirium, myocardial injury, and atrial fibrillation.

Trial Registration

ClinicalTrials.gov Identifier: NCT02361944.

Early Impressions and Adoption of the AtriAmp for Managing Arrhythmias Following Congenital Heart Surgery

AtriAmp is a new medical device that displays a continuous real-time atrial electrogram on telemetry using temporary atrial pacing leads. Our objective was to evaluate early adoption of this device into patient care within our pediatric intensive care unit (PICU). This is a qualitative study using inductive analysis of semi-structured interviews to identify dominant themes. The study was conducted in a single-center, tertiary, academic 21-bed mixed PICU. The subjects were PICU multidisciplinary team members (Pediatric Cardiac Intensivists, PICU Nurse Practitioners, PICU nurses and Pediatric Cardiologists) who were early adopters of the AtriAmp (n = 14). Three prominent themes emerged: (1) Accelerated time from arrhythmia event to diagnosis and treatment; (2) Increased confidence in the accuracy of providers' arrhythmia diagnosis; and (3) Improvement in the ability to educate providers about post-operative arrhythmias. Providers also noted some learning curves, but none compromised medical care or clinical workflow. Insights from early adopters of AtriAmp signal the need for simplicity and fidelity in new PICU technologies. Our research suggests that such technologies can be pivotal to the support and growth of multi-disciplinary teams, even among those who do not participate in early implementation. Further research is needed to understand when and why novel technology adoption becomes widespread in high-stakes settings.

New-onset postoperative atrial fibrillation after pulmonary endarterectomy is associated with adverse outcomes

Background

New-onset postoperative atrial fibrillation (POAF) is a common complication after pulmonary thromboendarterectomy (PEA), yet the risk factors and their impact on prognosis remain poorly understood. This study aims to investigate the risk factors associated with new-onset POAF after PEA and elucidate its underlying connection with adverse postoperative outcomes.

Methods

A retrospective analysis included 129 consecutive chronic thromboembolic pulmonary hypertension (CTEPH) patients and 16 sarcoma patients undergoing PEA. Univariate and multivariate analyses were conducted to examine the potential effects of preoperative and intraoperative variables on new-onset POAF following PEA. Propensity score matching (PSM) was then employed to adjust for confounding factors.

Results

Binary logistic regression revealed that age (odds ratio [OR] = 1.041, 95% confidence interval [CI] = 1.008-1.075, p = 0.014) and left atrial diameter[LAD] (OR = 1.105, 95% CI = 1.025-1.191, p = 0.009) were independent risk factors for new-onset POAF after PEA. The receiver operating characteristic (ROC) curve indicated that the predictive abilities of age and LAD for new-onset POAF were 0.652 and 0.684, respectively. Patients with new-onset POAF, compared with those without, exhibited a higher incidence of adverse outcomes (in-hospital mortality, acute heart failure, acute kidney insufficiency, reperfusion pulmonary edema). Propensity score matching (PSM) analyses confirmed the results.

Conclusion

Advanced age and LAD independently contribute to the risk of new-onset POAF after PEA. Patients with new-onset POAF are more prone to adverse outcomes. Therefore, heightened vigilance and careful monitoring of POAF after PEA are warranted.

The association of hemoglobin with postoperative delirium and atrial fibrillation after cardiac surgery: a retrospective sub-study

BACKGROUND

Most cardiac surgery patients experience postoperative anemia. Delirium and Atrial Fibrillation (AF) are common and independent predictors of morbidity and mortality. Few reports examine their association with postoperative anemia. This study aims to quantify the association between anemia and these outcomes in patients undergoing cardiac surgery.

METHODS

This post-hoc analysis of the DECADE randomized controlled trial ran at six academic US hospitals. Patients aged 18-85 years with heart rate > 50 bpm undergoing cardiac surgery who had daily hemoglobin measurements in the first 5 Postoperative Days (POD) were included. Delirium was assessed twice daily with the Confusion Assessment Method for the ICU (CAM - ICU), preceded by the Richmond Agitation and Sedation Scale, with patients excluded from assessment if sedated. Patients had daily hemoglobin measurements, continuous cardiac monitoring plus twice-daily 12-lead electrocardiograms, up to POD4. AF was diagnosed by clinicians blinded to hemoglobin levels.

RESULTS

Five hundred and eighty-five patients were included. Mean postoperative hemoglobin Hazard Ratio (HR): 0.99 (95% CI 0.83, 1.19; p = 0.94) per 1 g.dL-1 hemoglobin decrease. 197 (34%) developed AF, mainly on POD = 2.3. Estimated HR = 1.04 (95% CI 0.93, 1.17; p = 0.51) per 1 g.dL-1 hemoglobin decrease.

CONCLUSIONS

Most patients undergoing major cardiac surgery were anemic in the postoperative phase. AF and delirium occurred in 34% and 12% of patients, respectively, but neither were significantly correlated with postoperative hemoglobin.

Scores predicting atrial fibrillation after mitral valve surgery: Do we need a more specific score?

Background

Atrial fibrillation after cardiac surgery (POAF) is associated with increased morbidity and mortality. Several scores were used to predict POAF, with variable results. Thus, this study assessed the performance of several scoring systems to predict POAF after mitral valve surgery. Additionally, we identified the risk factors for POAF in those patients.

Methods

This retrospective cohort included 1381 recruited from 2009 to 2021. The patients underwent mitral valve surgery, and POAF occurred in 233 (16.87%) patients. The performance of CHADS2, CHA2DS2-VASc, POAF, EuroSCORE II, and HATCH scores was evaluated.

Results

The median age was higher in patients who developed POAF (60 vs. 54 years; p < .001). CHA2-DS2-VASc, POAF, EuroSCORE II, and HATCH scores significantly predicted POAF, with areas under the curve of the receiver operator curve (AUCROC) of 0.56, 0.61, 0.58, and 0.54, respectively. We identified age > 58 years, body mass index > 28 kg/m2, creatinine clearance < 90 mL/min, reoperative surgery, and preoperative inotropic and intra-aortic balloon pump use as predictors of POAF. We constructed a score from these variables (PSCC-AF). A score > 2 significantly predicted POAF (p < .001). The AUCROC of this score was 0.67, which was significantly higher than the AUCROC of the POAF score (p = .009).

Conclusion

POAF after mitral valve surgery can be predicted based on preoperative patient characteristics. The new PSCC-AF score significantly predicted POAF after mitral valve surgery and can serve as a bedside diagnostic tool for POAF risk screening. Further studies are needed to validate the PSCC-AF-mitral score externally.

Neurohumoral Markers of Cardiac Autonomic Denervation after Surgical Ablation of Long-Standing Persistent Atrial Fibrillation

Although the autonomic nervous system has an evident impact on cardiac electrophysiology and radiofrequency ablation (RFA) is the conventional technique for treating persistent atrial fibrillation, the specific effects of RFA have been insufficiently studied to date. Here, we investigated whether RFA affects neurohumoral transmitter levels and myocardial 123I-metaiodobenzylguanidine (123I-MIBG) uptake. To perform this task, we compared two groups of patients with acquired valvular heart disease: patients who had undergone surgical AF ablation and patients with sinus rhythm. The decrease in norepinephrine (NE) level in the coronary sinus had a direct association with the heart-to-mediastinum ratio (p = 0.02) and a negative correlation with 123I-MIBG uptake defects (p = 0.01). The NE level decreased significantly after the main surgery, both in patients with AF (p = 0.0098) and sinus rhythm (p = 0.0039). Furthermore, the intraoperative difference between the norepinephrine levels in the ascending aorta and coronary sinus (ΔNE) of -400 pg/mL was determined as a cut-off value to evaluate RFA efficacy, as denervation failed in all patients with ΔNE < -400 pg/mL. Hence, ΔNE can be utilized to predict the efficacy of the "MAZE-IV" procedure and to assess the risk of AF recurrence after RFA.

The role of Del Nido Cardioplegia in reducing postoperative atrial fibrillation after cardiac surgery in patients with impaired cardiac function

BACKGROUND

Postoperative atrial fibrillation (POAF) occurs in 20% to 40% of patients who underwent cardiac surgery and can compromise the postoperative course, especially in those with reduced left ventricular ejection fraction. The most common causes are related to surgical trauma and the high variations in volemic and electrolyte balance in the postoperative period.

OBJECTIVES

As cardioplegic solutions can significantly impact both these factors, the study aimed to assess the role of Del Nido (DN) cardioplegia on the onset of POAF.

METHODS

A retrospective single-center analysis was carried out on 93 patients undergoing coronary artery bypass graft surgery where cardioplegia was used. The patients were divided into two groups according to the cardioplegic solution (Cold Blood vs Del Nido), and perioperative outcomes were compared.

RESULTS

POAF occurred in 21.5% of patients; the patients treated with cold blood cardioplegia (CBC) showed a 3-times higher rate of POAF compared to the DN group (OR: 3.44; 95% CI: 1.1 to 10.5; p = 0.029). The CBC group showed higher serum potassium levels both after the cross-clamp removal (p<0.001), at the ICU admission (p = 0.007), and during the first 3 postoperative days (p = 0.009). The defibrillation rate at cross-clamp removal (p = 0.003), the dose of postoperative epinephrine (p<0.001), and the peak of serum troponin (p = 0.01), were lower in the DN Group.

CONCLUSION

DN cardioplegia showed significantly reduced POAF rates after cardiac surgery by acting on the electrolyte balance, myocardial protection and on the need for postoperative inotropic support.

Relationship of Fibroblast Growth Factor 23 With Hospitalization for Heart Failure and Cardiovascular Outcomes in Patients Undergoing Cardiac Surgery

Background Fibroblast growth factor 23 (FGF-23) is crucial in regulating phosphate and vitamin D metabolism and is moreover associated with an increased cardiovascular risk. The specific objective of this study was to investigate the influence of FGF-23 on cardiovascular outcomes, including hospitalization for heart failure (HHF), postoperative atrial fibrillation, and cardiovascular death, in an unselected patient population after cardiac surgery. Methods and Results Patients undergoing elective coronary artery bypass graft and/or cardiac valve surgery were prospectively enrolled. FGF-23 blood plasma concentrations were assessed before surgery. A composite of cardiovascular death/HHF was chosen as primary end point. A total of 451 patients (median age 70 years; 28.8% female) were included in the present analysis and followed over a median of 3.9 years. Individuals with higher FGF-23 quartiles showed elevated incidence rates of the composite of cardiovascular death/HHF (quartile 1, 7.1%; quartile 2, 8.6%; quartile 3, 15.1%; and quartile 4, 34.3%). After multivariable adjustment, FGF-23 modeled as a continuous variable (adjusted hazard ratio for a 1-unit increase in standardized log-transformed biomarker, 1.82 [95% CI, 1.34-2.46]) as well as using predefined risk groups and quartiles remained independently associated with the risk of cardiovascular death/HHF and the secondary outcomes, including postoperative atrial fibrillation. Reclassification analysis indicated that the addition of FGF-23 to N-terminal pro-B-type natriuretic peptide provides a significant improvement in risk discrimination (net reclassification improvement at the event rate, 0.58 [95% CI, 0.34-0.81]; P<0.001; integrated discrimination increment, 0.03 [95% CI, 0.01-0.05]; P<0.001). Conclusions FGF-23 is an independent predictor of cardiovascular death/HHF and postoperative atrial fibrillation in individuals undergoing cardiac surgery. Considering an individualized risk assessment, routine preoperative FGF-23 evaluation may improve detection of high-risk patients.

Analysis of risk factors for perioperative complications in spine surgery

Complications in spine surgery can arise in the intraoperative or the immediate postoperative period or in a delayed manner. These complications may lead to severe or even permanent morbidity if left undiagnosed and untreated. We prospectively interviewed 526 patients out of 1140 patients who consecutively underwent spinal surgery in our department between November 2017 and November 2018 and analysed the outcome and complication rates. A 12 months follow-up period was also adopted. We analysed the patients' clinical characteristics, comorbidities, surgical management, survival rates, and outcomes. Risk factor analyses for the development of complications were also performed. Patients' median age was 67 years (range: 13-96). The main diagnoses were as follows: degenerative in 50%, tumour in 22%, traumatic fractures in 13%, infections in 10%, reoperations in 3%, and others in 2%. Surgeries were emergency procedures (within 24 h) in 12%. Furthermore, 59% required instrumentation. The overall postoperative complication rate was 26%. Revision surgery was required in 12% of cases within 30 postoperative days (median time to revision 11 days [IQR 5-15 days]). The most frequent complications included wound healing disorders, re-bleeding, and CSF leakage. Thereby, the risk factor analysis revealed age-adjusted CCI (p = 0.01), metastatic tumour (p = 0.01), and atrial fibrillation (p = 0.02) as significant risk factors for postoperative complications. Additionally, postoperative KPS (p = 0.004), postoperative anaemia (p = 0.001), the length of hospital stay (p = 0.02), and duration of surgery (p = 00.002) were also identified as associated factors. Complication rates after spinal surgeries are still high, especially in patients with metastatic tumour disease and poor clinical status (KPS), requiring revision surgeries in several cases. Therefore, specific risk factors should be determined to carefully select surgery groups.

Nurse Staffing Practices and Postoperative Atrial Fibrillation Among Cardiac Surgery Patients: A Multisite Cohort Study

BACKGROUND

Postoperative atrial fibrillation (POAF) is a frequent complication of cardiac surgery that is associated with increased morbidity, mortality, and costs. Recent studies suggest that nurse staffing practices are associated with adverse postoperative events, but whether these practices are also related to POAF occurrence is unknown.

METHODS

To fill this knowledge gap, a cohort of 6401 cardiac surgery patients admitted to 2 Canadian university health centres (UHC A and UHC B) between 2014 and 2018 was studied. Patients' cumulative exposure to 4 staffing practices (registered nurse [RN] understaffing, education, experience, and non-RN skill mix) was measured every shift over the first 6 postoperative days, during which 96% of POAF cases occur. The associations of these exposures with in-hospital POAF occurrence were estimated using site-specific multivariable logistic regression models and a mixed-effect model combining data from both sites.

RESULTS

Overall, 563 (27.2%) and 1336 (30.8%) cases of POAF occurred at UHC A and UHC B, respectively. In site-specific models, every 5% increase in the cumulative proportion of understaffed shifts over the first 6 postoperative days was associated with a 3.5% increase in the odds of POAF (adjusted odds ratio [aOR] for UHC A: 1.035; 95% confidence interval [CI]: 1.000-1.070, P = 0.0472; aOR for UHC B: 1.035; 95% CI: 1.013-1.057, P = 0.0019). In the mixed-effect model combining data from both sites, RN understaffing remained significant and was associated with a 3.1% increase in the odds of POAF (aOR: 1.031; 95% CI: 1.014-1.048, P = 0.0003). No other staffing practices were significantly associated with POAF occurrence.

CONCLUSION

Higher RN understaffing postoperatively is associated with increased POAF occurrence among cardiac surgery patients.

Ivabradine and Atrial Fibrillation: A Meta-analysis of Randomized Controlled Trials

ABSTRACT

This was a meta-analysis of randomized control trials (RCTs) to evaluate the effect of ivabradine on the risk of atrial fibrillation (AF) as well as its effect on the ventricular rate in patients with AF. The PubMed, EMBASE, Cochrane Controlled Trials Register, and other databases were searched for RCTs of ivabradine. Thirteen trials with 37,533 patients met the inclusion criteria. The incidence of AF was significantly higher in the ivabradine treatment group than in the control group (odds ratio (OR), 1.23; 95% confidence interval (CI), 1.08-1.41), although it was reduced after cardiac surgery (OR, 0.70; 95% CI, 0.23-2.12). Regarding left ventricular ejection fraction (LVEF), ivabradine increased the risk of AF in both LVEF >40% (OR, 1.42; 95% CI, 1.24 to 1.63) and LVEF ≤40% subgroups (OR, 1.16; 95% CI, 0.98-1.37). The risk of AF was increased by both small and large cumulative doses of ivabradine (small cumulative dose: OR, 3.00; 95% CI, 0.48 to 18.93; large cumulative dose: OR, 1.05; 95% CI, 0.83-1.34). Furthermore, ivabradine may reduce the ventricular rate in patients with AF. In conclusion, we found that both large and small cumulative doses of ivabradine were associated with an increased incidence of AF, and the effect was more marked in the LVEF >40% subgroup. Nevertheless, ivabradine therapy is beneficial for the prevention of post-operative AF. Furthermore, ivabradine may be effective in controlling the ventricular rate in patients with AF, although more RCTs are needed to support this conclusion.

A double-blind randomised controlled trial on the effect of Tocovid, a tocotrienol-rich capsule on postoperative atrial fibrillation at the National Heart Institute, Kuala Lumpur: an interim blinded analysis

INTRODUCTION

Post-operative atrial fibrillation (POAF) is associated with poorer outcomes, increased resource utilisation, morbidity and mortality. Its pathogenesis is initiated by systemic inflammation and oxidative stress. It is hypothesised that a potent antioxidant and anti-inflammatory agent such as tocotrienol, an isomer of Vitamin E, could reduce or prevent POAF.

AIMS

The aim of this study is to determine whether a potent antioxidative and anti-inflammatory agent, Tocovid, a tocotrienol-rich capsule, could reduce the incidence of POAF and affect the mortality and morbidity as well as the duration of ICU, HDU and hospital stay.

METHODS

This study was planned as a prospective, randomised, controlled trial with parallel groups. The control group received placebo containing palm superolein while the treatment group received Tocovid capsules. We investigated the incidence of POAF, the length of hospital stay after surgery and the health-related quality of life.

RESULTS

Recruitment commenced in January 2019 but the preliminary results were unblinded as the study is still ongoing. Two-hundred and two patients have been recruited out of a target sample size of 250 as of January 2021. About 75% have completed the study and 6.4% were either lost during follow-up or withdrew; 4% of participants died. The mean age group was 61.44 ± 7.30 years with no statistical difference between the groups, with males having a preponderance for AF. The incidence of POAF was 24.36% and the mean time for developing POAF was 55.38 ± 29.9 h post-CABG. Obesity was not a predictive factor. No statistically significant difference was observed when comparing left atrial size, NYHA class, ejection fraction and the premorbid history. The mean cross-clamp time was 71 ± 34 min and the mean bypass time was 95 ± 46 min, with no difference between groups. There was a threefold increase in death among patients with POAF (p = 0.008) and an increase in the duration of ICU stay (p = 0.01), the total duration of hospital stay (p = 0.04) and reintubation (p = 0.045).

CONCLUSION

A relatively low incidence rate of POAF was noted although the study is still ongoing. It remains to be seen if our prophylactic intervention using Tocovid would effectively reduce the incidence of POAF. Clinical Registration Number: US National Library of Medicine. Clinical Trials - NCT03807037. Registered on 16th January 2019. Link: https://clinicaltrials.gov/ct2/show/NCT03807037.

Atrial Electrography for Postoperative Tachyarrhythmia Analysis in Patients

The over 400,000 cardiac surgeries performed in the United States each year hold a risk for the postoperative complication of arrhythmias. Currently, bedside monitoring of surface electrocardiogram leads is used to interpret arrhythmias despite the evidence that atrial electrograms (AEGs) offer superior rhythm discrimination. This hesitancy to use the AEG may be due to a lack of training for practitioners in interpreting AEGs; therefore, our goal was to create an algorithm for the diagnosis of tachyarrhythmia using an AEG that can be utilized by any health care practitioner. Our algorithm classifies the most prevalent type of tachyarrhythmias following cardiac surgery. To allow rhythm identification, we categorized them based on their atrial to ventricular signal ratio, which is uniquely apparent on AEGs. Other considerations were given to rhythm regularity, consistency, P-wave axis, and rate. The algorithm includes the most common postoperative arrhythmias differentiated based on a unique branch-point approach, which walks through the steps in arrhythmia discrimination. Both rendered and collected AEGs are included as references for further understanding and interpretation of tachyarrhythmias. The utility of AEGs for rhythm discrimination post-cardiac surgery is established and recent technology can provide real-time and continuous monitoring; however, practitioner training may be inadequate. To bridge this divide, we created an algorithm so that existing atrial wires can be better used for an enhanced rhythm interpretation via AEGs.

Effectiveness and Safety of Oral Anticoagulants Among Nonvalvular Atrial Fibrillation Patients With Active Cancer

Background

Patients with cancer are more likely to develop nonvalvular atrial fibrillation (NVAF). Currently there are no definitive clinical trials or treatment guidelines for NVAF patients with concurrent cancer.

Objectives

This subgroup analysis of the ARISTOPHANES study compared the risk of stroke/systemic embolism (stroke/SE) and major bleeding (MB) among NVAF patients with active cancer who were prescribed non–vitamin K antagonist oral anticoagulants (NOACs) or warfarin.

Methods

A retrospective observational study was conducted in NVAF patients with active cancer who newly initiated apixaban, dabigatran, rivaroxaban, or warfarin from January 1, 2013, through September 30, 2015, with the use of Medicare and 4 U.S. commercial claims databases. Cox models were used to estimate the risk of stroke/SE and MB in the pooled propensity score–matched cohorts.

Results

A total of 40,271 patients were included, with main cancer types of prostate (29%), female breast (17%), genitourinary (14%), and lung (13%). Compared with warfarin, apixaban was associated with a lower risk of stroke/SE (hazard ratio [HR]: 0.59; 95% confidence interval [CI]: 0.45-0.78) and MB (HR: 0.58; 95% CI: 0.50-0.68); dabigatran and rivaroxaban had similar risks of stroke/SE (dabigatran: HR: 0.88 [95% CI: 0.54-1.41]; rivaroxaban: HR: 0.82 [95% CI: 0.62-1.08]) and MB (dabigatran: HR: 0.76 [95% CI: 0.57-1.01]; rivaroxaban: HR: 0.95 [95% CI: 0.85-1.06]). Risks of stroke/SE and MB varied among NOAC-NOAC comparisons, while consistent treatment effects were seen for all treatment comparisons across key cancer types.

Conclusions

Among this cohort of NVAF patients with active cancer, the risk of stroke/SE and MB varied among oral anticoagulants and were consistent across cancer types.

Machine Learning Outperforms Existing Clinical Scoring Tools in the Prediction of Postoperative Atrial Fibrillation During Intensive Care Unit Admission After Cardiac Surgery

OBJECTIVE(S)

Using the Medical Information Mart for Intensive Care III (MIMIC-III) database, we compared the performance of machine learning (ML) to the to the established gold standard scoring tool (POAF Score) in predicting postoperative atrial fibrillation (POAF) during intensive care unit (ICU) admission after cardiac surgery.

METHODS

Random forest classifier (RF), decision tree classifier (DT), logistic regression (LR), K neighbours classifier (KNN), support vector machine (SVM), and gradient boosted machine (GBM) were compared to the POAF Score. Cross-validation was used to assess the area under the receiver operating characteristic curve (AUC), sensitivity, and specificity of ML models. POAF Score performance confidence intervals were generated using 1,000 bootstraps. Risk profiles for GBM were generated using Shapley additive values.

RESULTS

A total of 6,349 ICU admissions encompassing 6,040 patients were included. POAF occurred in 1,364 of the 6,349 admissions (21.5%). For predicting POAF during ICU admission after cardiac surgery, GBM, LR, RF, KNN, SVM and DT achieved an AUC of 0.74 (0.71-0.77), 0.73 (0.71-0.75), 0.72 (0.69-0.75), 0.68 (0.67-0.69), 0.67 (0.66-0.68) and 0.59 (0.55-0.63) respectively. The POAF Score AUC was 0.63 (0.62-0.64). Shapley additive values analysis of GBM generated patient level explanations for each prediction.

CONCLUSION

Machine learning models based on readily available preoperative data can outperform clinical scoring tools for predicting POAF during ICU admission after cardiac surgery. Explanatory models are shown to have potential in personalising POAF risk profiles for patients by illustrating probabilistic input variable contributions. Future research is required to evaluate the clinical utility and safety of implementing ML-driven tools for POAF prediction.

Association of Pain With Atrial Fibrillation and Delirium After Cardiac Surgery: A DECADE Sub-Study

OBJECTIVE

The authors aimed to evaluate the effects of postoperative pain on the incidence of atrial fibrillation and delirium in patients having surgery with cardiopulmonary bypass (CPB).

DESIGN

Post hoc analysis of the (An investigator-initiated, multicentre, double-blind trial (ClinicalTrials NCT02004613) (DECADE)), a randomized, placebo-controlled trial.

SETTING

Tertiary, academic hospital.

PARTICIPANTS

Six hundred five adults from the DECADE enrolled at Cleveland Clinic Main Campus, who had had surgery with CPB.

INTERVENTIONS

Dexmedetomidine versus placebo started before surgical incision and postoperatively was maintained until 24 hours.

MEASUREMENTS

Primary outcomes were atrial fibrillation, diagnosed by clinicians in the intensive care unit (ICU), presence of delirium assessed with the Confusion Assessment Method for the ICU, data on pain scores, and opioid consumption, occurring between ICU admission and the earlier of postoperative day five or hospital discharge.

RESULTS

Postoperative pain levels were similar among patients with or without atrial fibrillation. Two hundred six (34%) patients had atrial fibrillation and ninety-two (15%) had delirium before hospital discharge within the first five postoperative days. The risk of atrial fibrillation was not significantly different between groups (hazard ratio: 1.09; 97.5% confidence interval [CI]: 0.99, 1.20, p = 0.039); there were no associations between postoperative pain and the risk of postoperative delirium (hazard ratio: 0.96; 97.5% CI: 0.84-1.11; p = 0.57). Postoperative opioid consumption was neither significantly associated with postoperative atrial fibrillation nor delirium.

CONCLUSIONS

Atrial fibrillation and delirium was not associated with pain after cardiac surgery. Opioid use was not associated with atrial fibrillation and delirium. Because both atrial fibrillation and delirium have a multifactorial nature, further studies should be focused on other plausible mechanisms.

The Prognostic Potential of Atrial Natriuretic Peptide on the Development of Postoperative Atrial Fibrillation after Cardiac Surgery

Background Postoperative atrial fibrillation (POAF) represents a common complication after cardiac surgery associated with major adverse events and poor patient outcome. Tools for risk stratification of this arrhythmia remain scarce. Atrial natriuretic peptide (ANP) represents an easily assessable biomarker picturing atrial function and strain; however, its prognostic potential on the development of POAF has not been investigated so far.

Methods Within the present investigation, 314 patients undergoing elective cardiac surgery were prospectively enrolled. Preoperative mid-region proANP (MR-proANP) values were assessed before the surgical intervention. Patients were followed prospectively and continuously screened for the development of arrhythmic events.

Results A total of 138 individuals (43.9%) developed POAF. Median concentrations of MR-proANP were significantly higher within the POAF group (p < 0.001). MR-proANP showed a strong association with the development of POAF with a crude odds ratio (OR) of 1.68 per 1 standard deviation (1-SD; 95% confidence interval [CI]: 1.31–2.15; p < 0.001), which remained stable after comprehensive adjustment for confounders with an adjusted OR of 1.74 per 1-SD (95% CI: 1.17–2.58; p = 0.006). The discriminatory power of MR-proANP for the development of POAF was validated by the category-free net reclassification improvement (0.23 [95% CI: 0.0349–0.4193]; p = 0.022) and integrated discrimination increment (0.02 [95% CI: 0.0046–0.0397], p = 0.013).

Conclusion MR-proANP proved to be a strong and independent predictor of the development of POAF. Considering a personalized diagnostic and prognostic preoperative work-up, a standardized preoperative evaluation of MR-proANP levels might help to identify patients at risk for development of POAF after cardiac surgery.

Eleutheroside B, a selective late sodium current inhibitor, suppresses atrial fibrillation induced by sea anemone toxin II in rabbit hearts

Eleutheroside B (EB) is the main active constituent derived from the Chinese herb Acanthopanax senticosus (AS) that has been reported to possess cardioprotective effects. In this study we investigated the effects of EB on cardiac electrophysiology and its suppression on atrial fibrillation (AF). Whole-cell recording was conducted in isolated rabbit atrial myocytes. The intracellular calcium ([Ca²⁺]_i) concentration was measured using calcium indicator Fura-2/AM fluorescence. Monophasic action potential (MAP) and electrocardiogram (ECG) synchronous recordings were conducted in Langendorff-perfused rabbit hearts using ECG signal sampling and analysis system. We showed that EB dose-dependently inhibited late sodium current (I_NaL), transient sodium current (I_NaT), and sea anemone toxin II (ATX II)-increased I_NaL with IC₅₀ values of 167, 1582, and 181 μM, respectively. On the other hand, EB (800 μM) did not affect L-type calcium current (I_CaL), inward rectifier potassium channel current (I_K), and action potential duration (APD). Furthermore, EB (300 μM) markedly decreased ATX II-prolonged the APD at 90% repolarization (APD₉₀) and eliminated ATX II-induced early afterdepolarizations (EADs), delayed afterdepolarizations (DADs), and triggered activities (TAs). Moreover, EB (200 μM) significantly suppressed ATX II-induced Na⁺-dependent [Ca²⁺]_i overload in atrial myocytes. In the Langendorff-perfused rabbit hearts, application of EB (200 μM) or TTX (2 μM) substantially decreased ATX II-induced incidences of atrial fibrillation (AF), ventricular fibrillation (VF), and heart death. These results suggest that augmented I_NaL alone is sufficient to induce AF, and EB exerts anti-AF actions mainly via blocking I_NaL, which put forward the basis of pharmacology for new clinical application of EB.

Investigation of the Effect of HATCH Score and Coronary Artery Disease Complexity on Atrial Fibrillation after On-Pump Coronary Artery Bypass Graft Surgery

OBJECTIVE

Postoperative atrial fibrillation (PoAF) is the most frequently encountered rhythm problem after coronary artery bypass graft (CABG) surgery. This situation decreases the capacity of the patients with respect to functional exercise and creates a risk for stroke. In this study, we aimed to determine the effect of coronary artery disease extensiveness and HATCH score on PoAF in patients undergoing CABG surgery with cardiopulmonary bypass.

SUBJECTS AND METHODS

Patients who underwent CABG between December 2014 and December 2018 were included retrospectively. Preoperative demographic characteristics, laboratory parameters, and operative parameters of the patients were recorded retrospectively.

RESULTS

Of the 352 patients, 274 had HATCH scores ≤2 (71.1% male, mean age: 61.7 ± 12.4 years), and 78 had HATCH scores >2 (69.2% male, mean age: 65.9 ± 11.7 years). Significant differences were found between the 2 groups in terms of the age (p = 0.014), presence of hypertension (p = 0.012), PoAF (p < 0.001), and SYNTAX (synergy between percutaneous coronary intervention with taxus and cardiac surgery) score I (p = 0.001). A HATCH score >2 and SYNTAX score I were identified as independent predictors of PoAF (OR: 1.022, 95% CI: 1.004-1.128, p = 0.032, and OR 1.098, 95% CI 1.035-1.164, p = 0.002, respectively). For predicting PoAF, the cutoff level in the ROC curve analysis was 19.7 for SYNTAX score (AUC 0.647, 95% CI 0.581-0.714, p < 0.001, 72.2% sensitivity and 66.4% specificity), and the cutoff level for HATCH score was 2 (AUC 0.656, 95% CI 0.595-0.722, p < 0.001, 69.4% sensitivity and 56.8% specificity) Conclusions: HATCH and SYNTAX scores are predictors of PoAF.

[Atrial Fibrillation After Coronary Artery Bypass Surgery: Risk Factors, Prevention and Treatment]

This review focuses on the issue of atrial fibrillation (AF) following coronary bypass surgery in patients with ischemic heart disease. Risk factors of this complication are discussed in detail. The authors addressed the effect of diabetes mellitus on development of postoperative AF. Data on current methods for prevention and treatment of AF are provided.

ABCA1 Polymorphism Is Associated With the Warfarin-Induced Aortic Stiffness After Coronary Artery Bypass Surgery in the Chinese Population

Warfarin is the most widely prescribed oral anticoagulant and is recommended for patients recovering from coronary artery bypass graft (CABG) with atrial fibrillation. Increasing evidence suggested that warfarin increased arterial stiffness in those patients. We aimed to examine the effect of warfarin therapy on aortic stiffness in patients who underwent CABG with or without postoperative warfarin treatment and explored the potential relationships of warfarin therapy with ABCA1 polymorphisms. This was a retrospect observational study of 24 patients who were continuously treated with warfarin were selected as the warfarin group and matched them by age (±3 years) and gender to 48 patients with nonuse of warfarin as the control group. The aortic stiffness, cholesterol efflux capacity, and plasma level of PIVKA-II were measured. Two ABCA1 polymorphisms were genotyped. Compared with baseline, treatment with warfarin for 1 year significantly increased the plasma level of PIVKA-II and aortic stiffness in pulse pressure and pulse wave velocity in patients after CABG. The increase of pulse wave velocity and plasma PIVKA-II level in the TT genotype was significantly greater than the CC genotype when comparing the -565C/T genotypes. The capacity of cholesterol efflux was significantly lower in the TT genotype at baseline and 1-year follow-up than the CC genotype. Postoperative treatment of warfarin for 1 year significantly increased aortic stiffness in patients who underwent CABG. ABCA1 -565C/T polymorphisms affected the cholesterol efflux capacity and were associated with the vitamin K status and the increased aortic stiffness after warfarin treatment in those patients.

Path to precision: prevention of post-operative atrial fibrillation

Development of post-operative atrial fibrillation (POAF) following open-heart surgery is a significant clinical and economic burden. Despite advancements in medical therapies, the incidence of POAF remains elevated at 25-40%. Early work focused on detecting arrhythmias from electrocardiograms as well as identifying pre-operative risk factors from medical records. However, further progress has been stagnant, and a deeper understanding of pathogenesis and significant influences is warranted. With the advent of more complex machine learning (ML) algorithms and high-throughput sequencing, we have an unprecedented ability to capture and predict POAF in real-time. Integration of multimodal heterogeneous data and application of ML can generate a paradigm shift for diagnosis and treatment. This will require a concerted effort to consolidate and streamline real-time data. Herein, we will review the current literature and emerging opportunities aimed at predictive targets and new insights into the mechanisms underlying long-term sequelae of POAF.

Preventive effect of low-dose landiolol on postoperative atrial fibrillation study (PELTA study)

Objective

To investigate the efficacy of prophylactic administration of low-dose landiolol on postoperative atrial fibrillation (POAF) in patients after cardiovascular surgery.

Methods

Consecutive 150 patients over 70 years of age who underwent cardiovascular surgery for valvular, ischemic heart, and aortic diseases were enrolled in this single-center prospective randomized control study from 2010 to 2014. They were assigned to three treatment groups: 1γ group (landiolol at 1 μg/kg/min), 2γ group (landiolol at 2 μg/kg/min), or control group (no landiolol). In the two landiolol groups, landiolol hydrochloride was intravenously administered for a period of 4 days postoperatively. Electrocardiography was continuously monitored during the study period, and cardiologists eventually assessed whether POAF occurred or not.

Results

POAF occurred in 24.4% of patients in the control group, 18.2% in 1γ group, and 11.1% in 2γ group (p = 0.256). Multivariate logistic regression analysis showed that the incidence of POAF tended to decrease depending on the dose of landiolol (trend-p = 0.120; 1γ group: OR = 0.786, 95% CI 0.257–2.404; 2γ group: OR = 0.379, 95% CI 0.112–1.287). Subgroup analysis showed a significant dose-dependent reduction in POAF among categories of female sex, non-use of angiotensin II receptor blockers (ARBs) before surgery, and valve surgery (each trend-p = 0.02, 0.03, and 0.004).

Conclusions

These findings indicate that prophylactic administration of low-dose landiolol may not be effective for preventing the occurrence of POAF in overall patients after cardiovascular surgery, but the administration could be beneficial to female patients, patients not using ARBs preoperatively, and those after valvular surgery.

Association between new-onset postoperative atrial fibrillation and 1-year mortality in elderly patients after hip arthroplasty

BACKGROUND

The purpose of this study is to determine whether new-onset postoperative atrial fibrillation (NOPAF) among patients after hip arthroplasty can predict 1-year mortality.

METHODS

All patients over 65 years who underwent hip arthroplasty from January 2013 to December 2017 in a Chinese tertiary hospital were retrospectively analyzed. Patients with paroxysmal and persistent atrial fibrillation were ruled out. 2438 patients were identified to be eligible. The primary endpoint was 1-year mortality after the arthroplasty.

RESULTS

Among the 2438 patients, 101 (4.1%) had NOPAF and 2337 (95.9%) had not. Only the current use of beta blocker could predict the occurrence of NOPAF after hip arthroplasty. 1-year mortality for patients with NOPAF was significantly higher than that for patients without NOPAF (70.3% vs 19.0%; p < 0.001). Anti-arrhythmic and anticoagulant treatments were related to 1-year mortality, respectively. With multivariate analysis, NOPA was the most significant variable related to 1-year mortality (hazard ratio 7.8, 95% CI 2.9-24.6).

CONCLUSIONS

Among elderly patients after hip arthroplasty, 1-year mortality is increased significantly for patients with NOPAF.

Atrial fibrillation in adults with congenital heart disease following cardiac surgery in a single center: Analysis of incidence and risk factors

OBJECTIVE

The primary aim of our work is to determine the incidence of atrial fibrillation following cardiac surgery in adults with congenital heart disease. Secondary aims include identifying risk factors predictive of developing early postoperative atrial fibrillation and morbidities associated with early postoperative atrial fibrillation.

DESIGN

Retrospective analysis.

SETTING

Single center, quaternary care children's hospital.

PATIENTS

This review included patients at least 18 years of age with known congenital heart disease who underwent cardiac surgery requiring a median sternotomy at our congenital heart center from January 1, 2012 to December 31, 2016.

INTERVENTIONS

None.

OUTCOME MEASURES

The primary outcome was early postoperative atrial fibrillation. Secondary outcomes included preoperative comorbidities, preoperative echocardiographic findings, operative details, and postoperative morbidities, such length of stay, reintubation, stroke, and death.

RESULTS

The incidence of early postoperative atrial fibrillation was 21%. Those who developed early postoperative atrial fibrillation were older (50 years vs 38 years, P =< .001), had a history of atrial fibrillation prior to surgery, had preoperative pulmonary hypertension, and had longer cardiopulmonary bypass times (103 minutes vs 84 minutes, P = .025) when compared to those who did not develop postoperative atrial fibrillation. Multivariate analysis identified age greater than 60, preoperative pulmonary hypertension, mitral valve intervention, and the need for postoperative inotropic support as being independent predictors of postoperative atrial fibrillation. Those who developed postoperative atrial fibrillation remained in the hospital longer (9 days vs 7 days, P =< .001).

CONCLUSIONS

Atrial fibrillation is a common complication following cardiac surgery in adults with congenital heart disease. Age, preoperative comorbidities, type of surgical intervention, and the need for perioperative inotropic infusions may predict the risk of atrial fibrillation in this unique patient population.

Atrial fibrillation after lung surgery: incidence, underlying factors, and predictors

Introduction

Cardiac complications are the second most common cause of morbidity and mortality in patients subjected to thoracic surgery after respiratory complications. Postoperative arrhythmia is one of the most common cardiac complications in these patients. It leads to morbidity, increased hospitalization, and high costs for patients.

Aim

To determine the incidence of atrial fibrillation after lung resection and determine the underlying factors and predictors of this problem.

Material and methods

The participants in this study were composed of all patients who were subjected to lung resection surgery in the past 4 years. The demographic data of the patients and possible postoperative complications, including the incidence of atrial fibrillation, were extracted from patient records. The statistical analysis of data was performed after data collection.

Results

The incidence of postoperative atrial fibrillation (POAF) in the present study was 7.6% (n = 20), mostly in patients who had a lung parenchyma resection. It occurred due to malignancy (n = 16), squamous cell carcinoma (n = 9), adenoid cystic carcinoma (n = 5), and metastasis (n = 2). The POAF occurred in 34.2% of pneumonectomy cases and 4.5% of lobectomy cases, out of whom 60% were male. There was a significant difference between the two groups of arrhythmia and non-arrhythmia groups regarding the age range. The mean ages of patients with and without arrhythmias were 56.45 ±18.2 and 44.76 ±17.2, respectively.

Conclusions

Pulmonary malignant pathologies are more likely to develop POAF due to the need for lung resection and possibly mediastinal lymphadenectomy that stimulates the heart and pericardium and the vagus nerve.

Benefits of Fasting Abbreviation with Carbohydrates and Omega-3 Infusion During CABG: a Double-Blind Controlled Randomized Trial

Objective

To assess postoperative clinical data considering the association of preoperative fasting with carbohydrate (CHO) loading and intraoperative infusion of omega-3 polyunsaturated fatty acids (ω-3 PUFA).

Methods

57 patients undergoing coronary artery bypass grafting (CABG) were randomly assigned to receive 12.5% maltodextrin (200 mL, 2 h before anesthesia), (CHO, n=14); water (200 mL, 2 h before anesthesia), (control, n=14); 12.5% maltodextrin (200 mL, 2 h before anesthesia) plus intraoperative infusion of ω-3 PUFA (0.2 g/kg), (CHO+W3, n=15); or water (200 mL, 2 h before anesthesia) plus intraoperative infusion of ω-3 PUFA (0.2 g/kg), (W3, n=14). The need for vasoactive drugs was analyzed, in addition to postoperative inflammation and metabolic control.

Results

There were two deaths (3.5%). Patients in CHO groups presented a lower incidence of hospital infection (RR=0.29, 95% CI 0.09-0.94; P=0.023), needed fewer vasoactive drugs during surgery and ICU stay (P<0.05); and had better blood glucose levels in the first six hours of recovery (P=0.015), requiring less exogenous insulin (P=0.018). Incidence of postoperative atrial fibrillation (POAF) varied significantly among groups (P=0.009). Subjects who receive ω-3 PUFA groups had fewer occurrences of POAF (RR=4.83, 95% CI 1.56-15.02; P=0.001). Patients in the W3 group had lower ultrasensitive-CRP levels at 36 h postoperatively (P=0.008). Interleukin-10 levels varied among groups (P=0.013), with the highest levels observed in the postoperative of patients who received intraoperative infusion of ω-3 PUFA (P=0.049).

Conclusion

Fasting abbreviation with carbohydrate loading and intraoperative infusion of ω-3 PUFA is safe and supports faster postoperative recovery in patients undergoing on-pump CABG.

Clinical effects of intravenous to oral amiodarone transition strategies in critically ill adult patients

WHAT IS KNOWN AND OBJECTIVE

There is limited guidance on how to transition critically ill patients from intravenous (IV) to oral (PO) amiodarone. The objective of this study was to assess the impact of IV and PO amiodarone overlap on short-term tachyarrhythmia recurrence and adverse hemodynamic outcomes in the intensive care unit.

METHODS

This is a retrospective, single-center analysis of critically ill adults who were treated with IV amiodarone for a supraventricular arrhythmia with rapid ventricular rate (RVR) and transitioned to PO amiodarone while inpatient. Patients were excluded if rate control was not achieved prior to the PO transition. Receipt of concomitant IV and PO therapy for ≤2 hours was considered no overlap (NOV) and >2 hours was considered overlap (OV). Tachyarrhythmia recurrence and adverse hemodynamic events were compared between groups.

RESULTS

A total of 90 patients (45 NOV, 45 OV) were included in the analysis. The median overlap duration was 0.1 (-1.3 to 1.2) hours in the NOV arm and 4 (2.6-6.1) hours in the OV arm. Recurrence of RVR occurred in 9 (20%) patients in each arm (P = 1.0). The median time from IV discontinuation to return of tachyarrhythmia was 10.5 hours. There were no significant differences in amiodarone dosing, electrolyte abnormalities, volume status or concomitant cardiac medications at the time of IV to PO transition. Hypotension occurred in 13% and 20% (P = 0.369) and bradycardia in 9% and 13% (P = 0.502) of patients in the NOV and OV arms, respectively.

WHAT IS NEW AND CONCLUSION

Providing IV and PO overlap of amiodarone for a median of 4 hours did not decrease the rate of early tachyarrhythmia recurrence. Future studies are warranted to evaluate the impact of alternative amiodarone dosing strategies on breakthrough tachyarrhythmia.

Biomarkers of Atrial Fibrillation: Which One Is a True Marker?

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmias and associated with the risk of stroke and death. Continuous development of the diagnostic tool and prognostic stratification may lead to optimal management of AF. The use of biomarkers in the management of AF has been grown as an interesting topic. However, the AF biomarkers are not yet well established in the major guidelines. Among these biomarkers, a lot of data show troponin and brain natriuretic peptides are promising for the prediction of future events. The troponin elevation in AF patients may not necessarily be diagnosed as myocardial infarction or significant coronary artery stenosis, and brain natriuretic peptide elevation may not necessarily confirm heart failure. Troponin T and troponin I may predict postoperative AF. Furthermore, troponin and brain natriuretic peptide gave better prognostic performance when compared with the risk score available today.

Postoperative atrial fibrillation following cardiac surgery: a persistent complication

Postoperative atrial fibrillation (POAF) is a common, expensive and potentially morbid complication following cardiac surgery. POAF occurs in around 35% of cardiac surgery cases and has a peak incidence on postoperative day 2. Patients who develop POAF incur on average $10 000-$20 000 in additional hospital treatment costs, 12-24 h of prolonged ICU time, and an additional 2 to 5 days in the hospital. POAF has been identified as an independent predictor of numerous adverse outcomes, including a 2- to 4-fold increased risk of stroke, reoperation for bleeding, infection, renal or respiratory failure, cardiac arrest, cerebral complications, need for permanent pacemaker placement, and a 2-fold increase in all-cause 30-day and 6-month mortality. The pathogenesis of POAF is incompletely understood but likely involves interplay between pre-existing physiological components and local and systemic inflammation. POAF is associated with numerous risk factors including advanced age, pre-existing conditions that cause cardiac remodelling and certain non-cardiovascular conditions. Clinical management of POAF includes both prophylactic and therapeutic measures, although the efficacy of many interventions remains in question. This review provides a comprehensive and up-to-date summary of the pathogenesis of POAF, outlines current clinical guidelines for POAF prophylaxis and management, and discusses new avenues for further investigation.

CD4+CD28null T Lymphocytes are Associated with the Development of Atrial Fibrillation after Elective Cardiac Surgery

Post-operative atrial fibrillation (POAF) is postulated as a complex interaction of different pathogenic factors, suggesting inflammatory processes as a main trigger of this particular type of atrial fibrillation. Therefore, the study sought to assess the impact of cellular immunity on the development of POAF. Comparing patients developing POAF to individuals free of POAF the fraction of CD4⁺CD28^null T Lymphocytes was significantly higher in individuals developing POAF (11.1% [POAF] vs. 1.9% [non-POAF]; p < 0.001). CD4⁺CD28^null cells were independently associated with the development of POAF with an adjusted odds ratio per one standard deviation of 4.89 (95% CI: 2.68–8.97; p < 0.001). Compared to N-terminal Pro-Brain Natriuretic Peptide, the fraction of CD4⁺CD28^null cells demonstrated an increased discriminatory power for the development of POAF (NRI: 87.9%, p < 0.001; IDI: 30.9%, p < 0.001). Interestingly, a pre-operative statin-therapy was associated with a lower fraction of CD4⁺CD28^null cells (p < 0.001) and showed an inverse association with POAF (p < 0.001). CD4⁺CD28^null cells proved to be predictive for the development of POAF after cardiac surgery. Our results potentially indicate an auto-immune impact of this preexisting, highly cytotoxic T cell subset in the pathogenesis of POAF, which might be modified via the anti-inflammatory potential of a pre-operative statin-therapy.

Can dexmedetomidine reduce atrial fibrillation after cardiac surgery? A systematic review and meta-analysis

Purpose

Cardiac surgery patients always present with atrial fibrillation (AF) after admission to the intensive care unit, leading to high mortality and lengthy hospitalization. Dexmedetomidine (DEX) is a popular medication used for sedation in the intensive care unit; however, whether it can reduce AF needs to be analyzed.

Materials and methods

Three primary databases, Medline, Embase (Ovid SP) and the Cochrane Central Register of Controlled Trials (CENTRAL), were searched. All English language and randomized control designed clinical publications comparing DEX to control medicines for sedation after elective cardiac surgery were included. Two independent colleagues conducted the data extraction and quality assessments. The subgroup analysis was performed according to the medicine used, age, AF history, and whether previous beta-blocker premedication and cardiopulmonary bypass (CPB) were applied. The overall incidence of AF was analyzed.

Results

A total of 1,295 patients in nine studies met the selection criteria among 2,587 studies screened from the database. After quantitative synthesis, our results revealed that the DEX group was not associated with a decreased incidence of AF compared with the placebo (risk ratio [RR] 0.76, 95% CI 0.37, 1.55, P=0.44) and morphine groups (RR 0.86, 95% CI 0.56, 1.31, P=0.48). Subgroup analysis also indicated that the DEX vs propofol comparison exhibited no difference: 1) for patients of age >60 years (P=0.69) or ≤60 years (P=0.69); 2) under CPB surgery (P=0.45) or without CPB surgery (P=0.88); 3) with beta-blocker premedication (P=0.32) or without beta-blocker premedication (P=0.90); and 4) with AF history (RR 1.07, 95% CI 0.85, 1.36, P=0.57) or without AF history (P=0.30).

Conclusion

This meta-analysis revealed that DEX could not reduce the incidence of AF compared to control medicines following cardiac surgery. DEX may have an increased influence on AF occurrence if patients had a history of AF. However, cautious interpretation should be made due to high clinical heterogeneity.

Autonomic Nervous System and Stress to Predict Secondary Ischemic Events after Transient Ischemic Attack or Minor Stroke: Possible Implications of Heart Rate Variability

Transient ischemic attack (TIA) and minor stroke have high risks of recurrence and deterioration into severe ischemic strokes. Risk stratification of TIA and minor stroke is essential for early effective treatment. Traditional tools have only moderate predictive value, likely due to their inclusion of the limited number of stroke risk factors. Our review follows Hans Selye’s fundamental work on stress theory and the progressive shift of the autonomic nervous system (ANS) from adaptation to disease when stress becomes chronic. We will first show that traditional risk factors and acute triggers of ischemic stroke are chronic and acute stress factors or “stressors,” respectively. Our first review shows solid evidence of the relationship between chronic stress and stroke occurrence. The stress response is tightly regulated by the ANS whose function can be assessed with heart rate variability (HRV). Our second review demonstrates that stress-related risk factors of ischemic stroke are correlated with ANS dysfunction and impaired HRV. Our conclusions support the idea that HRV parameters may represent the combined effects of all body stressors that are risk factors for ischemic stroke and, thus, may be of important predictive value for the risk of subsequent ischemic events after TIA or minor stroke.

Does dexmedetomidine have an antiarrhythmic effect on cardiac patients? A meta-analysis of randomized controlled trials

Background

Cardiac surgery patients often experience several types of tachyarrhythmias after admission to the intensive care unit (ICU), which increases mortality and morbidity. Dexmedetomidine (DEX) is a popular medicine used for sedation in the ICU, and its other pharmacological characteristics are gradually being uncovered.

Purpose

To determine whether DEX has an antiarrhythmic effect after cardiac surgery.

Methods

The three primary databases MEDLINE, Embase (OVID SP) and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched, and all English-language and randomized control-designed clinical publications comparing DEX to control medicines for sedation after elective cardiac surgery were included. Two colleagues independently extracted the data and performed other quality assessments. A subgroup analysis was performed according to the different medicines used and whether cardiopulmonary bypass (CPB) was applied. All tachyarrhythmias that occurred in the atria and ventricles were analyzed.

Results

A total of 1295 patients in 9 studies met the selection criteria among 2587 studies that were screened. After quantitative synthesis, our results revealed that the DEX group was associated with a lower incidence of ventricular arrhythmia (VA, OR 0.24, 95% CI 0.09–0.64, I² = 0%, P = 0.005) than the control group. Subgroup analysis did not reveal a significant difference between the DEX and propofol subgroups (OR 0.13, 95% CI 0.03–0.56, I² = 0%, P = 0.007). Additionally, no difference in the incidence of atrial fibrillation (AF) was observed regardless of the different control medicines (OR 0.82, 95% CI 0.60–1.10, I² = 25%, P = 0.19) or whether CPB was applied.

Conclusions

This meta-analysis revealed that DEX has an antiarrhythmic effect that decreases the incidence of VA compared to other drugs used for sedation following cardiac surgery. DEX may not have an effect on AF, but cautious interpretation should be exercised due to high heterogeneity.

Simultaneous recordings of intrinsic cardiac nerve activity and skin sympathetic nerve activity from human patients during the postoperative period

BACKGROUND

Intrinsic cardiac nerve activity (ICNA) and skin nerve activity (SKNA) are both associated with cardiac arrhythmias in dogs.

OBJECTIVE

The purpose of this study was to test the hypothesis that ICNA and SKNA correlate with postoperative cardiac arrhythmias in humans.

METHODS

Eleven patients (mean age 60 ± 13 years; 4 women) were enrolled in this study. Electrical signals were simultaneously recorded from electrocardiogram (ECG) patch electrodes on the chest wall and from 2 temporary pacing wires placed during open heart surgery on the left atrial epicardial fat pad. The signals were filtered to display SKNA and ICNA. Premature atrial contractions (PACs) and premature ventricular contractions were determined manually. The SKNA and ICNA of the first 300 minutes of each patient were calculated minute by minute to determine baseline average amplitudes of nerve activities and to determine their correlation with arrhythmia burden.

RESULTS

We processed 1365 ± 973 minutes of recording per patient. Low-amplitude SKNA and ICNA were present at all time, while the burst discharges were observed much less frequently. Both SKNA and burst ICNA were significantly associated with the onset of PACs and premature ventricular contractions. Baseline average ICNA (aICNA), but not average SKNA, had a significant association with PAC burden. The correlation coefficient (r) between aICNA and PAC burden was 0.78 (P < .01). A patient with the greatest aICNA developed postoperative atrial fibrillation.

CONCLUSION

ICNA and SKNA can be recorded from human patients in the postoperative period. The baseline magnitude of ICNA correlates with PAC burden and development of postoperative atrial fibrillation.

Preoperative carbohydrate load and intraoperatively infused omega-3 polyunsaturated fatty acids positively impact nosocomial morbidity after coronary artery bypass grafting: a double-blind controlled randomized trial

Background

A strategy of limited preoperative fasting, with carbohydrate (CHO) loading and intraoperative infusion of omega-3 polyunsaturated fatty acids (ω-3 PUFA), has seldom been tried in cardiovascular surgery. Brief fasting, followed by CHO intake 2 h before anesthesia, may improve recovery from CABG procedures and lower perioperative vasoactive drug requirements. Infusion of ω-3 PUFA may reduce occurrences of postoperative atrial fibrillation (POAF) and shorten hospital stays. The aim of this study was to assess morbidity (especially POAF) in ICU patients after coronary artery bypass grafting (CABG)/cardiopulmonary bypass (CPB) in combination, if preoperative fasts are curtailed in favor of CHO loading, and ω-3 PUFA are infused intraoperatively.

Methods

Fifty-seven patients undergoing CABG were randomly assigned to receive 12.5% maltodextrin (200 ml, 2 h before anesthesia), without infusing ω-3 PUFA (CHO, n = 14); water (200 ml, 2 h before anesthesia), without infusing ω-3 PUFA (controls, n = 14); 12.5% maltodextrin (200 ml, 2 h before anesthesia) plus intraoperative ω-3 PUFA (0.2 mcg/kg) (CHO + W3, n = 15); or water (200 ml, 2 h before anesthesia) plus intraoperative ω-3 PUFA (0.2 mcg/kg) (W3, n = 14). Perioperative clinical variables and mortality were analyzed, examining the incidence of POAF, as well as the need for inotropic vasoactive drugs during surgery and in ICU.

Results

Two deaths occurred (3.5%), but there were no instances of bronchoaspiration and mediastinitis. Neither ICU stays nor total postoperative stays differed by group (P > 0.05). Patients given preoperative CHO loads (CHO and CHO + W3 groups) experienced fewer instances of hospital infection (RR = 0.29, 95%CI 0.09–0.94; P = 0.023) and were less reliant on vasoactive amines during surgery (RR = 0.60, 95% CI 0.38–0.94; P = 0.020). Similarly, the number of patients requiring vasoactive drugs while recovering in ICU differed significantly by group (P = 0.008), showing benefits in patients given CHO loads. The overall incidence of POAF was 29.8% (17/57), differing significantly by group (P = 0.009). Groups given ω-3 PUFA (W3 and CHO + W3 groups) experienced significantly fewer instances of POAF (RR = 4.83, 95% CI 1.56–15.02; P = 0.001).

Conclusion

Preoperative curtailment of fasting was safe in this cohort. When implemented in conjunction with CHO loading and infusion of ω-3 PUFA during surgery, expedited recovery from CABG with CPB was observed.

Trial registration

NCT: 03017001