Treatment strategies for new onset atrial fibrillation in patients treated on an intensive care unit: a systematic scoping review.

BACKGROUND: New-onset atrial fibrillation (NOAF) in patients treated on an intensive care unit (ICU) is common and associated with significant morbidity and mortality. We undertook a systematic scoping review to summarise comparative evidence to inform NOAF management for patients admitted to ICU. METHODS: We searched MEDLINE, EMBASE, CINAHL, Web of Science, OpenGrey, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Database of Abstracts of Reviews of Effects, ISRCTN, ClinicalTrials.gov, EU Clinical Trials register, additional WHO ICTRP trial databases, and NIHR Clinical Trials Gateway in March 2019. We included studies evaluating treatment or prevention strategies for NOAF or acute anticoagulation in general medical, surgical or mixed adult ICUs. We extracted study details, population characteristics, intervention and comparator(s), methods addressing confounding, results, and recommendations for future research onto study-specific forms. RESULTS: Of 3,651 citations, 42 articles were eligible: 25 primary studies, 12 review articles and 5 surveys/opinion papers. Definitions of NOAF varied between NOAF lasting 30 s to NOAF lasting > 24 h. Only one comparative study investigated effects of anticoagulation. Evidence from small RCTs suggests calcium channel blockers (CCBs) result in slower rhythm control than beta blockers (1 study), and more cardiovascular instability than amiodarone (1 study). Evidence from 4 non-randomised studies suggests beta blocker and amiodarone therapy may be equivalent in respect to rhythm control. Beta blockers may be associated with improved survival compared to amiodarone, CCBs, and digoxin, though supporting evidence is subject to confounding. Currently, the limited evidence does not support therapeutic anticoagulation during ICU admission. CONCLUSIONS: From the limited evidence available beta blockers or amiodarone may be superior to CCBs as first line therapy in undifferentiated patients in ICU. The little evidence available does not support therapeutic anticoagulation for NOAF whilst patients are critically ill. Consensus definitions for NOAF, rate and rhythm control are needed.

Multivariable prediction models for atrial fibrillation after cardiac surgery: a systematic review protocol.

INTRODUCTION: Dozens of multivariable prediction models for atrial fibrillation after cardiac surgery (AFACS) have been published, but none have been incorporated into regular clinical practice. One of the reasons for this lack of adoption is poor model performance due to methodological weaknesses in model development. In addition, there has been little external validation of these existing models to evaluate their reproducibility and transportability. The aim of this systematic review is to critically appraise the methodology and risk of bias of papers presenting the development and/or validation of models for AFACS. METHODS: We will identify studies that present the development and/or validation of a multivariable prediction model for AFACS through searches of PubMed, Embase and Web of Science from inception to 31 December 2021. Pairs of reviewers will independently extract model performance measures, assess methodological quality and assess risk of bias of included studies using extraction forms adapted from a combination of the Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies checklist and the Prediction Model Risk of Bias Assessment Tool. Extracted information will be reported by narrative synthesis and descriptive statistics. ETHICS AND DISSEMINATION: This systemic review will only include published aggregate data, so no protected health information will be used. Study findings will be disseminated through peer-reviewed publications and scientific conference presentations. Further, this review will identify weaknesses in past AFACS prediction model development and validation methodology so that subsequent studies can improve upon prior practices and produce a clinically useful risk estimation tool. PROSPERO REGISTRATION NUMBER: CRD42019127329.

Increased long-term mortality following new-onset atrial fibrillation in the intensive care unit: A systematic review and meta-analysis.

PURPOSE: We performed a systematic review and meta-analysis to investigate the long-term outcomes of patients who develop new-onset atrial fibrillation (NOAF) during an intensive care unit (ICU) admission. METHODS: We searched the MEDLINE and EMBASE databases from 2000 to 2022. We included studies of adults based in general ICUs that evaluated long-term outcomes (at least 30 days after hospital discharge) of NOAF. We excluded studies involving patients with a history of atrial fibrillation (AF). We performed risk of bias assessment of the included studies based on a modified Newcastle Ottawa score (NOS). We extracted summary data for long-term outcomes. Where the outcome was reported in three or more studies we pooled effect sizes. RESULTS: We screened 2206 studies and included 15 studies reporting data from 561,797 patients. Pooled analysis of 4 studies using a random effects model revealed an association between NOAF acquired in an ICU and 90-day mortality (including ICU and hospital mortality) (RR 1.53, 95% CI 1.12-2.08). We also found an association between NOAF and 1-year mortality from 7 studies (RR 1.79, 95% CI 1.65-1.96), which remained when analysing 1-year mortality in hospital survivors (RR 1.72 (95% CI 1.49-1.98). CONCLUSIONS: In patients who develop NOAF in an ICU, both 90-day and 1-year mortality are increased in comparison to those who do not develop NOAF. Current evidence suggests an increased risk of thromboembolic events after hospital discharge in patients who develop NOAF in an ICU.

Circadian variation in new-onset atrial fibrillation in patients in ICUs.

New-onset atrial fibrillation (NOAF) is common in patients treated on an intensive care unit (ICU). Onset of certain arrhythmias exhibit circadian variation. Whether NOAF follows a circadian rhythm in patients in ICU is unknown. We undertook a retrospective observational study of two ICU databases to explore the timing of NOAF onset. We identified 2017 patients who developed NOAF during their ICU stay. NOAF onset exhibited a bimodal distribution with peaks at 8 am and 8 pm, consistent with the onset of paroxysmal AF in patients in the community. Future studies in ICUs should record time of AF onset, as understanding high risk periods may inform timing of preventative interventions.

New-onset atrial fibrillation in intensive care: epidemiology and outcomes.

AIMS: New-onset atrial fibrillation (NOAF) is common in patients treated on an intensive care unit (ICU), but the long-term impacts on patient outcomes are unclear. We compared national hospital and long-term outcomes of patients who developed NOAF in ICU with those who did not, before and after adjusting for comorbidities and ICU admission factors. METHODS AND RESULTS: Using the RISK-II database (Case Mix Programme national clinical audit of adult intensive care linked with Hospital Episode Statistics and mortality data), we conducted a retrospective cohort study of 4615 patients with NOAF and 27 690 matched controls admitted to 248 adult ICUs in England, from April 2009 to March 2016. We examined in-hospital mortality; hospital readmission with atrial fibrillation (AF), heart failure, and stroke up to 6 years post discharge; and mortality up to 8 years post discharge. Compared with controls, patients who developed NOAF in the ICU were at a higher risk of in-hospital mortality [unadjusted odds ratio (OR) 3.22, 95% confidence interval (CI) 3.02-3.44], only partially explained by patient demographics, comorbidities, and ICU admission factors (adjusted OR 1.50, 95% CI 1.38-1.63). They were also at a higher risk of subsequent hospitalization with AF [adjusted cause-specific hazard ratio (aCHR) 5.86, 95% CI 5.33-6.44], stroke (aCHR 1.47, 95% CI 1.12-1.93), and heart failure (aCHR 1.28, 95% CI 1.14-1.44) independent of pre-existing comorbidities. CONCLUSION: Patients who develop NOAF during an ICU admission are at a higher risk of in-hospital death and readmissions to hospital with AF, heart failure, and stroke than those who do not.

Risk factors for new-onset atrial fibrillation during critical illness: A Delphi study.

Background: New-onset atrial fibrillation (NOAF) is common during critical illness and is associated with poor outcomes. Many risk factors for NOAF during critical illness have been identified, overlapping with risk factors for atrial fibrillation in patients in community settings. To develop interventions to prevent NOAF during critical illness, modifiable risk factors must be identified. These have not been studied in detail and it is not clear which variables warrant further study. Methods: We undertook an international three-round Delphi process using an expert panel to identify important predictors of NOAF risk during critical illness. Results: Of 22 experts invited, 12 agreed to participate. Participants were located in Europe, North America and South America and shared 110 publications on the subject of atrial fibrillation. All 12 completed the three Delphi rounds. Potentially modifiable risk factors identified include 15 intervention-related variables. Conclusions: We present the results of the first Delphi process to identify important predictors of NOAF risk during critical illness. These results support further research into modifiable risk factors including optimal plasma electrolyte concentrations, rates of change of these electrolytes, fluid balance, choice of vasoactive medications and the use of preventative medications in high-risk patients. We also hope our findings will aid the development of predictive models for NOAF.

Comparative effectiveness of common treatments for new-onset atrial fibrillation within the ICU: Accounting for physiological status.

BACKGROUND: New-onset atrial fibrillation (NOAF) is common in patients on an intensive care unit (ICU). Evidence guiding treatments is limited, though recent reports suggest beta blocker (BB) therapy is associated with reduced mortality. METHODS: We conducted a multicentre cohort study of adult patients admitted to 3 ICUs in the UK and 5 ICUs in the USA. We analysed the haemodynamic changes associated with NOAF. We analysed rate control, rhythm control, and hospital mortality associated with common NOAF treatments. We balanced admission and post-NOAF, pre-treatment covariates across treatment groups. RESULTS: NOAF was followed by a systolic blood pressure reduction of 5 mmHg (p < 0.001). After adjustment, digoxin therapy was associated with inferior rate control versus amiodarone (adjusted hazard ratio (aHR) 0.56, [95% CI 0.34-0.92]). Calcium channel blocker (CCB) therapy was associated with inferior rhythm control versus amiodarone (aHR 0.59 (0.37-0.92). No difference was detected between BBs and amiodarone in rate control (aHR 1.15 [0.91-1.46]), rhythm control (aHR 0.85, [0.69-1.05]), or hospital mortality (aHR 1.03 [0.53-2.03]). CONCLUSIONS: NOAF in ICU patients is followed by decreases in blood pressure. BBs and amiodarone are associated with similar cardiovascular control and appear superior to digoxin and CCBs. Accounting for key confounders removes previously reported mortality benefits associated with BB treatment.

Hospital outcomes associated with new-onset atrial fibrillation during ICU admission: A multicentre competing risks analysis.

PURPOSE: New onset atrial fibrillation (NOAF) in critically ill patients has been associated with increased short-term mortality. Analyses that do not take into account the time-varying nature of NOAF can underestimate its association with hospital outcomes. We investigated the prognostic association of NOAF with hospital outcomes using competing risks methods. MATERIALS AND METHODS: We undertook a retrospective cohort study in three general adult intensive care units (ICUs) in the UK from June 2008 to December 2015. We excluded patients with known prior atrial fibrillation or an arrhythmia within four hours of ICU admission. To account for the effect of NOAF on the rate of death per unit time and the rate of discharge alive per unit time we calculated subdistribution hazard ratios (SDHRs). RESULTS: Of 7541 patients that fulfilled our inclusion criteria, 831 (11.0%) developed NOAF during their ICU admission. NOAF was associated with an increased duration of hospital stay (CSHR 0.68 (95% CI 0.63-0.73)) and an increased rate of in-hospital death per unit time (CSHR 1.57 (95% CI 1.37-1.1.81)). This resulted in a strong prognostic association with dying in hospital (adjusted SDHR 2.04 (1.79-2.32)). NOAF lasting over 30 min was associated with increased hospital mortality. CONCLUSIONS: Using robust methods we demonstrate a stronger prognostic association between NOAF and hospital outcomes than previously reported.

Risk factors for new-onset atrial fibrillation on the general adult ICU: A systematic review.

PURPOSE: This study was performed to systematically review the available evidence for the risk factors for new-onset atrial fibrillation (NOAF) on the general adult intensive care unit (ICU) and provide a semi-quantitative evidence synthesis. METHODS: We searched the MEDLINE, EMBASE, Cochrane Database of Systematic Reviews and the CENTRAL databases from 1970 to 2018. We included studies of adults based in general ICUs that evaluated potential risk factors for NOAF. We excluded studies involving patients with a history of atrial fibrillation (AF). We semi-qualitatively evaluated the strength of evidence for each identified variable. RESULTS: We screened 1447 studies. Seventeen studies were included in the final analysis. We identified strong evidence for age, male sex, preceding cardiovascular disease, acute renal failure, acute respiratory failure, APACHE score and the use of vasopressors as risk factors for the development of NOAF on the ICU. Modifiable risk factors had not been studied in detail. CONCLUSIONS: We provide the first systematic review with evidence synthesis of risk factors for NOAF on the general adult ICU. Evidence for modifiable risk factors was limited. Further research is therefore required and may contribute towards the evidence-based prevention and management of this important condition.