Atrial fibrillation after coronary artery bypass grafting is associated with sympathetic activation

Biochemical Predictors of New-Onset Atrial Fibrillation after Ascending Aorta Replacement Surgery in Acute Type A Aortic Dissection Patients

Objective. This study aimed to determine the risk factors of new-onset postoperative atrial fibrillation after ascending aortic replacement in acute type A aortic dissection patients, with emphasis on biochemical parameters. Methods. From Jan 2020 to Dec 2021, a total of 435 acute type A aortic dissection patients who underwent ascending aortic replacement and without a history of atrial fibrillation were retrospectively analyzed in this study. Perioperative data of these patients were obtained from the hospital’s database. The 30-day follow-up was via telephone interviews. The multivariate regression analysis was used to identify risk factors that may be predictive of postoperative atrial fibrillation. Results. 218 (50.1%) patients experienced postoperative atrial fibrillation after ascending aorta replacement surgery. Older age (OR = 1.081 (1.059–1.104), $p<0.001$ ), higher total bile acid (OR = 1.064 (1.024–1.106), $p$  = 0.002), glucose (OR = 1.180 (1.038–1.342), $p$  = 0.012), and serum potassium (OR = 2.313 (1.078–4.960), $p$  = 0.031) were identified by multivariate regression analysis as risk factors of postoperative atrial fibrillation. The multivariate regression analysis prediction model incorporating these four factors had a good prediction effect (AUC = 0.769 (0.723–0.816), $p<0.001$ ). Conclusions. Older age, higher total bile acid, glucose, and serum potassium were risk factors of postoperative atrial fibrillation after ascending aortic replacement surgery in acute type A aortic dissection patients.

Cannabis, cocaine, methamphetamine, and opiates increase the risk of incident atrial fibrillation

AIMS

Atrial fibrillation (AF) is now regarded as a preventable disease, requiring a search for modifiable risk factors. With legalization of cannabis and more lenient laws regarding the use of other illicit substances, investigation into the potential effects of methamphetamine, cocaine, opiate, and cannabis exposure on incident AF is needed.

METHODS AND RESULTS

Using Office of Statewide Health Planning and Development databases, a longitudinal analysis was performed of adult Californians ≥18 years of age who received care in an emergency department, outpatient surgery facility, or hospital from 1 January 2005 to 31 December 2015. Associations between healthcare coding for the use of each substance and a new AF diagnosis were assessed. Among 23,561,884 patients, 98 271 used methamphetamine, 48 701 used cocaine, 10 032 used opiates, and 132 834 used cannabis. Of the total population, 998 747 patients (4.2%) developed incident AF during the study period. After adjusting for potential confounders and mediators, use of methamphetamines, cocaine, opiates, and cannabis was each associated with increased incidence of AF: hazard ratios 1.86 [95% confidence interval (CI) 1.81-1.92], 1.61 (95% CI 1.55-1.68), 1.74 (95% CI 1.62-1.87), and 1.35 (95% CI 1.30-1.40), respectively. Negative control analyses in the same cohort failed to reveal similarly consistent positive relationships.

CONCLUSION

Methamphetamine, cocaine, opiate, and cannabis uses were each associated with increased risk of developing incident AF. Efforts to mitigate the use of these substances may represent a novel approach to AF prevention.

Comparison of new-onset post-operative atrial fibrillation between patients receiving carvedilol and metoprolol after off-pump coronary artery bypass graft surgery

OBJECTIVE

Post-operative atrial fibrillation (POAF) is a common complication of coronary artery bypass graft (CABG) surgery. Previous studies suggest carvedilol is more effective than metoprolol in preventing POAF in on-pump CABG. This study investigated if the same benefit would be seen in off-pump CABG.

METHODS

This single-center, retrospective review compared rates of new-onset POAF between adult patients who received carvedilol and metoprolol after off-pump CABG surgery. Safety endpoints included hypotension, bradycardia, dyspnea, and the composite. Multivariate logistic regression was conducted to identify associations between demographics, potential confounders, and beta-blocker dose and POAF. Kaplan-Meier plots and Cox proportional-hazards models examined differences in time-to-event for POAF.

RESULTS

134 patients were included (34 carvedilol and 100 metoprolol). The mean age was 63 years, 70.9% were male, 85% had history of hypertension, 3.7% had history of heart failure with reduced ejection fraction, and 38.8% were taking beta blockers prior to admission. POAF developed in 2 patients (5.8%) in the carvedilol group and 24 patients (24.0%) in the metoprolol group (odds ratio 0.17 [95% CI 0.03-0.83], p = 0.023). Safety endpoints occurred in 10 carvedilol (29.4%) and 44 metoprolol (44.0%) patients (p = 0.134). Hypotension and dyspnea rates were similar between groups; bradycardia occurred more commonly among metoprolol-treated patients (p = 0.040). Time-to-event analyses revealed a hazard ratio = 0.22 (95% CI 0.05-0.93, p = 0.040) for carvedilol use.

CONCLUSIONS

In this single-center, retrospective study of off-pump CABG patients, carvedilol was associated with reduced POAF risk and enhanced safety compared to metoprolol.

Pericardial Effusion Provoking Atrial Fibrillation After Cardiac Surgery: JACC Review Topic of the Week

Postoperative atrial fibrillation (POAF) is the most common complication after cardiac surgery. Patients who develop POAF are more likely to experience adverse outcomes, including increased rates of death, stroke, heart failure, and hospitalizations, and higher hospital costs. Understanding the mechanisms underlying POAF is important to improve patients' outcome and optimize health systems' efficiency. Beyond classic pathogenic hypotheses, emerging evidence suggests that postoperative pericardial effusion and localized pericardial inflammation may trigger POAF. This hypothesis is supported by data from nonhuman animal models and a growing body of evidence showing that reducing postoperative pericardial effusion might reduce POAF incidence. In this review, we summarize the classic pathophysiology theories of POAF following cardiac surgery and discuss new etiologic mechanisms with a specific focus on the role of pericardial effusion and inflammation.

Short acting intravenous beta-blocker as a first line of treatment for atrial fibrillation after cardiac surgery: a prospective observational study

Post-operative atrial fibrillation (POAF) defined as a new-onset of atrial fibrillation (AF) following surgery occurs frequently after cardiac surgery. For non-symptomatic patients, rate control strategy seems to be as effective as rhythm control one in surgical patients. Landiolol is a new highly cardio-selective beta-blocker agent with interesting pharmacological properties that may have some interest in this clinical situation. This is a prospective, monocentric, observational study. All consecutive adult patients (age >18 years old) admitted in the intensive care unit following cardiac surgery with a diagnosed episode of AF were eligible. Success of landiolol administration was defined by a definitive rate control from the beginning of infusion to the 72th h. We also evaluated rhythm control following landiolol infusion. Safety analysis was focused on haemodynamic, renal and respiratory side effects. From 1 January 2020 to 30 June 2021, we included 54 consecutive patients. A sustainable rate control was obtained for 49 patients (90.7%). Median time until a sustainable rate control was 4 h (1, 22). Median infusion rate of landiolol needed for a sustainable rate control was 10 µg/kg/min (6, 19). Following landiolol infusion, median time until pharmacological cardioversion was 24 h. During landiolol infusion, maintenance of mean arterial pressure target requires a concomitant very low dose of norepinephrine. We did not find any other side effects. Low dose of landiolol used for POAF treatment was effective and safe for a rapid and sustainable rate and rhythm control after cardiac surgery.

Inflammatory continuum in the pathogenesis of atrial fibrillation after coronary bypass surgery

Atrial fibrillation (AF) after coronary bypass surgery is recorded in 20- 60% of patients and increase the early and long-term postoperative mortality. The aim of the review is to analyze the studies on causal relationships between damaging factors and the development of myocardial inflammation at each stage of surgical treatment in patients with multivessel coronary artery disease. In the review, myocardial inflammation is considered from the point of view of a continuum  — a chronic process that originates from the coronary endothelium damage and continuously proceeds within the AF pathogenesis after coronary bypass surgery. For the first time, the concept of inflammatory continuum for postoperative AF is introduced. The review discusses the main and latest laboratory and instrumental markers of local and systemic inflammatory response, which are informative in terms of severity and promising for improving approaches to the diagnosis and prevention of postoperative AF. The review was prepared using available materials from Russian and foreign library databases (PubMed, Medline, Web of Science and Cochrane Library). The search depth was >25 years since 1996. Based on the analysis of available studies, we concluded that inflammation is not just evidence of AF, but plays a causal role in its pathogenesis at each stage of surgical myocardial revascularization.

Post-operative Atrial Fibrillation Impacts on Outcomes in Transcatheter and Surgical Aortic Valve Replacement

Background: Atrial fibrillation (AF) in severe aortic stenosis (AS) has poor outcomes after transcatheter and surgical aortic valve replacement (TAVR and SAVR, respectively). We compared the incidence of AF after aortic valve replacement (AVR) according to the treatment method and the impact of AF on outcomes.

Methods: We investigated the incidence of AF and clinical outcomes of AVR according to whether AF occurred after TAVR and SAVR after propensity score (PS)-matching for 1 year follow-up. Clinical outcomes were defined as death, stroke, and admission due to heart failure. The composite outcome comprised death, stroke, and admission due to heart failure.

Results: A total of 221 patients with severe AS were enrolled consecutively, 100 of whom underwent TAVR and 121 underwent SAVR. The incidence of newly detected AF was significantly higher in the SAVR group before PS-matching (6.0 vs. 40.5%, P < 0.001) and after PS-matching (7.5 vs. 35.6%, P = 0.001). TAVR and SAVR showed no significant differences in outcomes except in terms of stroke. In the TAVR group, AF history did not affect the outcomes; however, in the SAVR group, AF history affected death (log rank P = 0.038). Post-AVR AF had a worse impact on admission due to heart failure (log rank P = 0.049) and composite outcomes in the SAVR group. Post-AVR AF had a worse impact on admission due to heart failure (log rank P = 0.008) and composite outcome in the TAVR group.

Conclusion: Post-AVR AF could be considered as a predictor of the outcomes of AVR. TAVR might be a favorable treatment option for patients with severe symptomatic AS who are at high-risk for AF development or who have a history of AF because the occurrence of AF was more frequent in the SAVR group.

Atrial Fibrillation after Lung Cancer Surgery: Prediction, Prevention and Anticoagulation Management

Simple Summary

Atrial fibrillation that occurs after surgery raises further questions with respect to spontaneous atrial fibrillation, being an event unquestionably related to the surgical act itself and always quite self-limiting. The purpose of this review is to present the knowledge gained so far, including the most recent findings, regarding this peculiar form of arrhythmia. Its prognostic impact and the possibility of predicting and preventing it were the subject of our analysis, as well as the similarities and differences with spontaneous atrial fibrillation in relation to anticoagulation. Where possible, the search for evidence has focused on studies involving lung cancer patients undergoing thoracic surgery, highlighting any differences with cardiac surgery.

Abstract

Atrial fibrillation (AF) is a common complication of the early postoperative period of various types of surgery, including that for lung cancer. Although induced by the homeostatic alterations related to surgery, there is evidence that it is not a mere stand-alone transitory event, but it represents a relevant complication of surgery, bearing considerable prognostic consequences. Different methods have therefore been explored to predict the occurrence of postoperative atrial fibrillation (POAF) and prevent it. In particular, the age among clinical factors, and N-terminal prohormone of brain natriuretic peptide (NT-proBNP), as a marker, have proven to be good predictors, and the use of beta-blockers or amiodarone in primary prevention seems to reduce its incidence significantly. There is growing evidence that POAF significantly increases the risk of stroke and global mortality in the long term; therefore, it should be managed in the same way as spontaneous atrial fibrillation. In this review, we will present the strongest evidence found so far and the most recent findings regarding the management of POAF, with a special focus on patients undergoing thoracic surgery for lung cancer.

Early postoperative statin administration does not affect the rate of atrial fibrillation after cardiac surgery

OBJECTIVES

Postoperative atrial fibrillation is the most frequent complication after cardiac surgery, and the use of statins in preventing them is being extensively studied. The aim of this study was to investigate whether a pause in the administration of statins affects the occurrence of atrial fibrillation after cardiac surgery in a prospective randomized and controlled setting.

METHODS

A total of 301 patients without chronic atrial fibrillation with prior statin medication scheduled for elective or urgent cardiac surgery involving the coronary arteries and/or heart valves were prospectively recruited and randomized for statin re-initiation on either the first (immediate statin group) or the fifth (late statin group) postoperative day, using the original medication and dosage. The immediate statin group comprised 146 patients and the late statin group 155 patients. Except for a somewhat higher rate of males (85% vs 73%, P = 0.016) in the immediate statin group, the baseline characteristics and the distribution of procedures performed within the groups were comparable. The occurrence of postoperative atrial fibrillation and the clinical course of the patients were compared between the groups.

RESULTS

The incidence of atrial fibrillation was 46% and the median delay after surgery before the onset of atrial fibrillation was 3 days in both groups (P = NS). No differences were observed in the frequency of the arrhythmia in any subgroup analyses or in other major complications or clinical parameters. No adverse effects related to early statin administration were detected.

CONCLUSIONS

Early re-initiation of statins does not appear to affect the occurrence of postoperative atrial fibrillation.

CLINICAL TRIAL REGISTRATION

European Union Drug Regulating Authorities Clinical Trials Database (EudraCT)-2016-001655-44.

Optimising risk factors for atrial fibrillation post-cardiac surgery

Postoperative atrial fibrillation (POAF) is an ongoing complication following cardiac surgery, with an incidence of 15%-60%. It is associated with substantial mortality and morbidity, as well increased hospital stays and healthcare costs. The pathogenesis is not fully understood, but the literature suggests that POAF occurs when transient, postoperative triggers act on vulnerable atrial tissue produced by preoperative, procedure-induced and postoperative processes such as inflammation, oxidative stress, autonomic dysfunction and electrophysiological remodelling of the atrial tissues. This sets the stage for arrhythmogenic mechanisms, such as ectopic firing secondary to triggered activity and re-entry mechanisms generating POAF. Preoperative factors include advanced age, sex, ethnicity, cardiovascular risk factors, preoperative drugs, electrocardiogram and echocardiogram abnormalities. Procedural factors include: the use of cardiopulmonary bypass and aortic cross clamp, type of cardiac surgery, use of hypothermia, left ventricular venting, bicaval cannulation and exclusion of the left atrial appendage. Postoperative factors include postoperative drugs, electrolyte and fluid balance and infection. This review explores the pathogenesis of POAF and the contribution of these perioperative factors in the development of POAF. Patients can be risk stratified for targeted treatment and prophylaxis, and how these factors can be attenuated to improve POAF outcomes following cardiac surgery.

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.

Human iPSC modelling of a familial form of atrial fibrillation reveals a gain of function of If and ICaL in patient-derived cardiomyocytes

AIMS

Atrial fibrillation (AF) is the most common type of cardiac arrhythmias, whose incidence is likely to increase with the aging of the population. It is considered a progressive condition, frequently observed as a complication of other cardiovascular disorders. However, recent genetic studies revealed the presence of several mutations and variants linked to AF, findings that define AF as a multifactorial disease. Due to the complex genetics and paucity of models, molecular mechanisms underlying the initiation of AF are still poorly understood. Here we investigate the pathophysiological mechanisms of a familial form of AF, with particular attention to the identification of putative triggering cellular mechanisms, using patient's derived cardiomyocytes (CMs) differentiated from induced pluripotent stem cells (iPSCs).

METHODS AND RESULTS

Here we report the clinical case of three siblings with untreatable persistent AF whose whole-exome sequence analysis revealed several mutated genes. To understand the pathophysiology of this multifactorial form of AF we generated three iPSC clones from two of these patients and differentiated these cells towards the cardiac lineage. Electrophysiological characterization of patient-derived CMs (AF-CMs) revealed that they have higher beating rates compared to control (CTRL)-CMs. The analysis showed an increased contribution of the If and ICaL currents. No differences were observed in the repolarizing current IKr and in the sarcoplasmic reticulum calcium handling. Paced AF-CMs presented significantly prolonged action potentials and, under stressful conditions, generated both delayed after-depolarizations of bigger amplitude and more ectopic beats than CTRL cells.

CONCLUSIONS

Our results demonstrate that the common genetic background of the patients induces functional alterations of If and ICaL currents leading to a cardiac substrate more prone to develop arrhythmias under demanding conditions. To our knowledge this is the first report that, using patient-derived CMs differentiated from iPSC, suggests a plausible cellular mechanism underlying this complex familial form of AF.

Surgical factors associated with new-onset postoperative atrial fibrillation after lung resection: the EPAFT multicentre study

PURPOSE OF THE STUDY

Postoperative atrial fibrillation (POAF) is a recognised complication in approximately 10% of major lung resections. In order to best target preoperative treatment, this study aimed at determining the association of incidence of POAF in patients undergoing lung resection to surgical and anatomical factors, such as surgical approach, extent of resection and laterality.

STUDY DESIGN

Evaluation of Post-operative Atrial Fibrillation in Thoracic surgery (EPAFT): a multicentre, population-based, retrospective, cross-sectional, observational study including 1367 patients undergoing lung resections between April 2016 and March 2017. The primary outcome was the presence of POAF following resection. POAF was defined as at least one episode of symptomatic or asymptomatic AF confirmed by ECG within 7 days from the thoracic procedure or prior to discharge from the hospital.

RESULTS

POAF was observed in 7.4% of patients: 3.1% in minor resection (video-assisted thoracoscopic surgery (VATS): 2.5%; thoracotomy: 3.8%), 9.0% in simple lobectomy (VATS: 7.3%, thoracotomy: 9.9%), 6.0% in complex resection (thoracotomy: 6.3%) and 11.4% in pneumonectomy. POAF was higher in left (4.0%) vs right (2.4%) minor resections, and in left (9.9%) vs right (8.3%) lobectomy, but higher in right (7.5%) complex resections, and the highest in right pneumonectomy (17.6%). No significant variations were observed as per sex, laterality or resected lobes. A positive univariable and multivariable association was observed for increasing age and increasing extent of resection, but not thoracotomy. Median (Q1-Q3) hospital stay was 9 (7-14) days in POAF and 5 (4-7) days in non-AF patients (p<0.001), with an increased cerebrovascular accident burden (p<0.001) and long-term mortality (p<0.001).

CONCLUSIONS

Among patients undergoing lung resection, POAF was significantly associated with age, increasing invasiveness of approach and increasing extent of resection. In addition, POAF carried a significant long-term mortality rate and burden of cerebrovascular accident. Appropriate prophylaxis should be targeted at these groups.

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

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

Perioperative glycemic control and its outcome in patients following open heart surgery

Background

Diabetes is not uncommon in patients requiring cardiac surgery. These patients have a higher incidence of morbidity and mortality. Subsequently, diabetes represents a major medico-economic problem in both developed and developing countries. This study was designed to observe the association between glycemic control and outcome of patients after open heart surgery in adult population.

Materials and Methods

Data was collected retrospectively in all patients who underwent open cardiac surgery (coronary artery bypass grafting, valve, or bypass grafting with valve surgery) and survived 72 hours postoperatively and had diabetes. The study was conducted from January 2015 to December 2016.

Results

Of the 129 patients included in the study, male dominated 101 (78.3%). Most frequent surgery was coronary artery bypass grafting (CABG) 123 (95.3%), CABG plus aortic valve replacement 4 (3.1%), and CABG plus mitral valve replacement 2 (1.6%). Considering diabetes, only 3 (2.3%) were on diet control, 112 (86.8%) on oral hypoglycemic agents (OHA), whereas 9 (7%) had control on both insulin and OHA. Only 5 (3.9%) had type I diabetes. The mean fasting blood sugar (FBS) was 154.58 g/dl, and the mean duration of diabetic mellitus was observed 12.32 years. Microvascular and macrovascular complications were 26/129 (20.16%) and 17/129 (13.17%), respectively. Total 75 (58.1%) patients did not require insulin and 54 (41.9%) were treated with insulin intraoperatively to keep the blood glucose level less than 200 g/dl. Cardiac arrhythmias were frequent in the insulin group (P < 0.05), which was also associated with increased stay in the cardiac intensive care unit.

Conclusion

Inadequate glycemic control during open cardiac surgery can possibly lead to increased perioperative morbidity and mortality and with decreased long-term survival and recurrent ischemic events. Therefore, aiming for blood glucose levels around 140 mg/dl appears reasonable. Further studies are required to define specific glucose ranges for a clearer definition of recommended blood glucose goals in postoperative cardiac patients for the best outcomes in patients with diabetes mellitus.

Late atrial arrhythmias after lung transplantation: a meta-analysis

BACKGROUND

Atrial arrhythmias are common following noncardiac thoracic surgery. In particular, early postoperative atrial arrhythmias after lung transplantation are very frequent, especially atrial fibrillation (AFib). Late atrial arrhythmia occurrence following lung transplantation, instead, has been less commonly reported.

METHODS

The aim of the present systematic review and meta-analysis is to analyse the incidence rate of late atrial arrhythmia and AFib in lung transplantation patients, with a special focus on double lung transplant (DLT), also to assess potential predictors of AFib occurrence. After bibliographic search (PUBMED/Medline and Embase databases), a random-effect model meta-analysis was performed: seven studies were finally included, including 2068 lung transplantation patients.

RESULTS

The pooled incidence rate of late atrial arrhythmia was 4.3%/year [95% confidence interval (CI) 2.8-6.1%/year, I = 69%], whereas late AFib incidence rate was 1.5%/year (95% CI 0.7-2.6%/year, I = 87%). In patients undergoing DLT, the pooled incidence rate of late atrial arrhythmia was 4.1%/year (95% CI 2.5-6.0%/year, I = 67%), while the AFib incidence rate was 0.9%/year (95% CI 0.1-2.4%/year, I = 92%). A longer follow-up duration significantly related to the reduced incidence rate of AFib (P = 0.02). History of AFib (hazard ratio 11.2, 95% CI 5.9-21.3) and early postoperative AFib (hazard ratio 10.3, 95% CI 5.9-18.0) emerged, instead, as relevant predictors of AFib occurrence.

CONCLUSION

Late atrial arrhythmia occurrence is not infrequent in lung transplantation patients; however, late Afib incidence was rare and showed a time-dependent decrease, particularly in DLT patients, suggesting that a transmural pulmonary veins isolation, the mainstay of transcatheter ablation, is effective in decreasing the likelihood of experiencing AFib.

Continuous Magnesium Infusion to Prevent Atrial Fibrillation After Cardiac Surgery: A Sequential Matched Case-Controlled Pilot Study

OBJECTIVE

The authors aimed to test whether a bolus of magnesium followed by continuous intravenous infusion might prevent the development of atrial fibrillation (AF) after cardiac surgery.

DESIGN

Sequential, matched, case-controlled pilot study.

SETTING

Tertiary university hospital.

PARTICIPANTS

Matched cohort of 99 patients before and intervention cohort of 99 consecutive patients after the introduction of a continuous magnesium infusion protocol.

INTERVENTIONS

The magnesium infusion protocol consisted of a 10 mmol loading dose of magnesium sulphate followed by a continuous infusion of 3 mmol/h over a maximum duration of 96 hours or until intensive care unit discharge.

MEASUREMENTS AND MAIN RESULTS

The study groups were balanced except for a lower cardiac index in the intervention cohort. The mean duration of magnesium infusion was 27.93 hours (95% confidence interval [CI]: 24.10-31.76 hours). The intervention group had greater serum peak magnesium levels: 1.72 mmol/L ± 0.34 on day 1, 1.32 ± 0.36 on day 2 versus 1.01 ± 1.14 and 0.97 ± 0.13, respectively, in the control group (p < 0.01). Atrial fibrillation occurred in 25 patients (25.3%) in the intervention group and 40 patients (40.4%) in the control group (odds ratio 0.49, 95% CI, 0.27-0.92; p = 0.023). On a multivariate Cox proportional hazards model, the hazard ratio for the development of AF was significantly less in the intervention group (hazard ratio 0.45, 95% CI, 0.26-0.77; p = 0.004).

CONCLUSION

The magnesium delivery strategy was associated with a decreased incidence of postoperative AF in cardiac surgery patients. These findings provide a rationale and preliminary data for the design of future randomized controlled trials.

New-onset postoperative atrial fibrillation after heart surgery

BACKGROUND

New-onset postoperative atrial fibrillation (poAF) complicates approximately 20-60% of all cardiac surgical procedures and is associated with an increased periprocedural mortality and morbitity, prolonged hospital stay, increased costs, and worse long-term survival. Unfortunately multiple advances in surgery and perioperative care over the last two decades have not led to a reduction in the incidence of poAF or associated complications in the daily clinical practice.

METHODS

A narrative review of the available literature was performed.

RESULTS

An extensive review of the pathophysiology of poAF following cardiac surgery, clinical, and procedural risk-factors is provided, as well as prophylactic measures and treatment.

CONCLUSION

Multiple strategies to prevent and manage poAF following heart surgery already exist. Our hope is that this review will facilitate more rigorous testing of prevention strategies, implementation of prophylaxis regimens as well as optimal treatment of this common and serious complication.

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.

Tolvaptan can limit postoperative paroxysmal atrial fibrillation occurrence after open-heart surgery

PURPOSE

Tolvaptan administration in the early postoperative period after cardiac surgery rapidly treats fluid retention without affecting the renal function. Tolvaptan also has the benefit of not stimulating the renin-angiotensin and sympathetic nervous systems, which are risk factors for postoperative paroxysmal atrial fibrillation. In this study, we examined the hypothesis that tolvaptan administration reduces postoperative paroxysmal atrial fibrillation and worsening of the renal function incidence in patients who have undergone open-heart surgery.

METHODS

From our previous randomized study, we selected 166 open-heart surgery patients, divided them into 2 groups [tolvaptan group, 83 patients; control (non-tolvaptan) group, 83 patients], and compared the incidence of postoperative paroxysmal atrial fibrillation and worsening of the renal function in the postoperative period between the groups.

RESULTS

The incidence of worsening of the renal function was significantly lower in the tolvaptan group than in the control group (4.8% vs. 15.7%; P = 0.04). The incidence of postoperative paroxysmal atrial fibrillation within 14 days was also significantly lower in the tolvaptan group than in the control group (26.5% vs. 42.2%; P = 0.011).

CONCLUSION

Tolvaptan administration in the early postoperative period after open-heart surgery may reduce the incidence of postoperative paroxysmal atrial fibrillation and worsening of the renal function.

Cardiac autonomic regulation and PR interval determination for enhanced atrial fibrillation risk prediction after cardiac surgery

BACKGROUND

Changes in cardiac autonomic regulation and P-wave characteristics are associated with the occurrence of atrial fibrillation. The purpose of this study was to evaluate whether combined preoperative non-invasive determination of cardiac autonomic regulation and PR interval allows for the identification of patients at risk of new-onset atrial fibrillation after cardiac surgery.

METHODS

RR, PR and QT intervals, and linear and non-linear heart rate variability parameters from 20 min high-resolution electrocardiographic recordings were determined one day before surgery in 150 patients on chronic beta blockers undergoing elective coronary artery bypass grafting, aortic valve replacement, or both, electively.

RESULTS

Thirty-one patients (21%) developed postoperative atrial fibrillation. In the atrial fibrillation group, more arterial hypertension, a greater age, a higher EuroSCORE II, a higher heart rate variability index (pNN50: 9 ± 20 vs. 4 ± 10, p = 0.050), a short PR interval (156 ± 23 vs. 173 ± 31 ms; p = 0.011), and a reduced short-term scaling exponent of the detrended fluctuation analysis (DFA1, 0.96 ± 0.36 vs. 1.11 ± 0.30 ms; p = 0.032) were found compared to the sinus rhythm group. Logistic regression modeling confirmed PR interval, DFA1 and age as the strongest preoperative predictors of postoperative atrial fibrillation (area under the receiver operating characteristic curve = 0.804).

CONCLUSIONS

Patients developing atrial fibrillation after cardiac surgery presented with severe cardiac autonomic derangement and a short PR interval preoperatively. The observed state characterizes both altered heart rate regulation and arrhythmic substrate and is strongly related to an increased risk of postoperative atrial fibrillation.

Incidence and Outcomes of Postoperative Atrial Fibrillation After Left Ventricular Assist Device

This study sought to determine the incidence, predictors, and outcomes of postoperative atrial fibrillation (POAF) in patients undergoing implantation of left ventricular assist devices (LVADs). A retrospective analysis of all patients who underwent LVAD implantation from 2013 to 2014 was conducted. Postoperative AF, survival, and thrombotic complications were evaluated after surgery. A total of 47 patients (mean age, 56.4 ± 12.5 years; 33 male) were included and followed for a median of 331 days. Within 30 days of surgery, 13 (28%) patients developed POAF at mean 7.9 ± 8.5 days. Obstructive lung disease was a predictor of POAF (p = 0.01). Postoperative AF was not associated with increased mortality, length of stay, or thrombotic complication within 30 days. Postoperative AF was predictive of recurrent new AF (24 vs. 5.5%) after 30 days of LVAD implantation. Also, POAF was associated with increased risk of ischemic stroke and device thrombosis during follow-up (p = 0.01). These results show that unlike in other cardiac surgery, POAF does not have a negative impact on early postoperative morbidity or mortality. However, POAF is a predictor for future AF, ischemic stroke, and device thrombosis.

Sympathetic Nervous System Activation and Its Modulation: Role in Atrial Fibrillation

The autonomic nervous system (ANS) has a significant influence on the structural integrity and electrical conductivity of the atria. Aberrant activation of the sympathetic nervous system can induce heterogeneous changes with arrhythmogenic potential which can result in atrial tachycardia, atrial tachyarrhythmias and atrial fibrillation (AF). Methods to modulate autonomic activity primarily through reduction of sympathetic outflow reduce the incidence of spontaneous or induced atrial arrhythmias in animal models and humans, suggestive of the potential application of such strategies in the management of AF. In this review we focus on the relationship between the ANS, sympathetic overdrive and the pathophysiology of AF, and the potential of sympathetic neuromodulation in the management of AF. We conclude that sympathetic activity plays an important role in the initiation and maintenance of AF, and modulating ANS function is an important therapeutic approach to improve the management of AF in selected categories of patients. Potential therapeutic applications include pharmacological inhibition with central and peripheral sympatholytic agents and various device based approaches. While the role of the sympathetic nervous system has long been recognized, new developments in science and technology in this field promise exciting prospects for the future.

Relation of Cannabis Use and Atrial Fibrillation Among Patients Hospitalized for Heart Failure

Left ventricular dysfunction triggers the activation of the sympathetic nervous system, providing inotropic support to the failing heart and concomitantly increasing the risk of atrial fibrillation (AF). The cardiovascular effects of cannabis have been characterized as biphasic on the autonomic nervous system with an increased sympathetic effect at low doses and an inhibitory sympathetic activity at higher doses. It is unknown if the autonomic effect of cannabis impacts the occurrence of AF in patients with heart failure (HF). We used data from the Healthcare Cost and Utilization Project-National Inpatient Sample for patients admitted with a diagnosis of HF in 2014. The outcome variable was the diagnosis of AF, with the main exposure being cannabis use. We identified a cannabis user group and a 1:1 propensity-matched non-cannabis user group, each having 3,548 patients. We then estimated the odds of AF diagnosis in cannabis users. An estimated 3,950,392 patients were admitted with a diagnosis of HF in the United States in 2014. Among these, there were 17,755 (0.45%) cannabis users. In the matched cohort, cannabis users were less likely to have AF (19.08% vs 21.39%; AOR 0.87 [0.77 to 0.98]). In conclusion, cannabis users have lower odds of AF when compared with nonusers, which was not explained by co-morbid conditions, age, insurance type, and socioeconomic status.

Post-operative left atrial volume index is a predictor of the occurrence of permanent atrial fibrillation after mitral valve surgery in patients who undergo mitral valve surgery

Background

Atrial fibrillation (AF) can occur even after the correction of mitral valve (MV) pathology in patients who have pre-operative sinus rhythm and undergo MV surgery. However, the factors associated with the occurrence of AF after MV surgery are still unclear. The aim of this retrospective study was to investigate the factors determining the occurrence of permanent AF after MV surgery in patients with preoperative sinus rhythm who underwent MV surgery.

Methods

Four hundred and forty-two patients (mean age 46 ± 12, 190 men) who underwent MV surgery and sinus rhythm were investigated retrospectively. Transthoracic echocardiography was performed before and after MV surgery at the time of dismissal.

Results

Permanent post-operative AF occurred in 81 (18%) patients even after successful MV surgery and preoperative sinus rhythm. It was more common in rheumatic etiology, a presence of mitral stenosis, lower pre- and post-operative left ventricular ejection fraction, higher post-operative mean diastolic pressure gradient across mitral prosthesis, larger post-operative left atrial volume index (LAVI) and lesser degrees of reduction in LAVI after surgery. In multiple regression analysis, post-operative LAVI was found to be an independent predictor for occurrence of AF. Post-operative LAVI > 39 ml/m2 was the cut-off value for best prediction of new onset permanent AF (sensitivity: 79%, AUC: 0.762, SE: 0.051, p < 0.001).

Conclusion

New-onset permanent post-operative AF is not uncommon, even after successful MV surgery despite pre-operative sinus rhythm. Larger post-operative LAVI was an independent predictor for the occurrence of AF.

Assessment the effect of dexmedetomidine on incidence of paradoxical hypertension after surgical repair of aortic coarctation in pediatric patients

OBJECTIVE

The aim of the study was to assess the effect of dexmedetomidine on the incidence of paradoxical hypertension in patients undergoing aortic coarctation repair.

DESIGN

Randomized observational study.

SETTING

University hospital and cardiac center.

PATIENTS

The study included 108 pediatric patients with isolated aortic coarctation.

METHODS

The patients were classified into two groups (each = 54): Group D: the patients received dexmedetomidine as a loading dose of 0.5 μg/kg over 10 min followed by infusion 0.3 μg/kg/h during surgery and continued for the first 48 postoperative hours. Group C: The patients received an equal amount of normal saline. The medication was prepared by the nursing staff and given to anesthetist blindly. The collected data included the heart rate, systolic and diastolic arterial blood pressure, incidence, onset, severity and treatment of paradoxical hypertension, fentanyl dose and end-tidal sevoflurane concentration, amount of blood loss and urine output.

MAIN RESULTS

The heart rate, systolic and diastolic blood pressure decreased significantly with dexmedetomidine than Group C (P < 0.05). The incidence and severity of the paradoxical hypertension was lower with dexmedetomidine than Group C (P = 0.011, P = 0.017, respectively). The onset the paradoxical hypertension was earlier in Group C than dexmedetomidine (P = 0.026). The dose of fentanyl and sevoflurane concentration decreased significantly with dexmedetomidine (P = 0.034, P = 0.026, respectively). The blood loss decreased with dexmedetomidine (P = 0.020) and the urine output increased with dexmedetomidine (P = 0.024). The incidence of hypotension and bradycardia was more with dexmedetomidine (P < 0.05).

CONCLUSION

Dexmedetomidine is safe in pediatric patients undergoing aortic coarctation repair. It minimized the incidence and severity of paradoxical hypertension. It decreased the required antihypertensive medications.

Incidence and risk factors for development of atrial fibrillation after cardiac surgery under cardiopulmonary bypass

Background and Aims

Atrial fibrillation (AF) is a common postoperative complication after cardiac surgery due to multifactorial causes. The aim of this study was to evaluate the incidence and risk factors of postoperative atrial fibrillation (POAF) after cardiac surgery under cardiopulmonary bypass (CPB).

Methods

A total of 150 adult patients undergoing coronary artery bypass graft (CABG) surgery and valvular surgeries were included. They were evaluated with respect to preoperative risk factors [age, use of β-blockers, left ventricular ejection fraction (LVEF), previous myocardial infarction (MI) and diabetes], intraoperative factors (CABG or valvular surgery, duration of CPB and aortic cross clamp time) and postoperative factors (duration of inotropic support and ventilatory support). Outcome measure was POAF after cardiac surgery under CPB. Postoperative intensive care unit and hospital stay and mortality were also studied.

Results

Of the patients who developed POAF, 50% were less than 60 years, 50.6% were diabetics, 50.7% had prior MI,19.7% had LVEF <40%, 82.6%were not on β-blockers, 66.7% had aortic cross clamp time >60 min and 60% had surgery with CPB time >100 min. About 38.8% underwent CABG and 43.1%underwent valvular surgery. There was a positive association with LVEF <40%, prior MI, post-bypass inotropic support greater than 10 min and ventilatory support more than 24 h with the development of POAF.

Conclusion

The incidence of POAF after cardiac surgery was 40.7%. Preoperative LVEF <0.4, prior MI, CPB time >100 minand extended ventilation for >24 h were significantly associated with POAF.

Th17/Treg Ratio in Serum Predicts Onset of Postoperative Atrial Fibrillation After Off-Pump Coronary Artery Bypass Graft Surgery

BACKGROUND

The aim of this study is to identify whether the balance between T helper 17 (Th17) cells and CD4⁺CD25⁺Foxp3⁺ regulatory T (Treg) cells could predict the postoperative atrial fibrillation (POAF) after coronary artery bypass graft surgery (CABG).

METHODS

We enrolled 88 patients from Xinhua Hospital who received off-pump CABG (OPCABG) surgery. The baseline characteristics of patients were recorded. The preoperative variables C-reactive protein (CRP) level, left atrial (LA) volume, EuroSCORE I score, CHADS₂ score, and CHA₂DS₂-VASc score were calculated at enrolment. Circulating Th17 and Treg cell frequencies were determined by flow cytometry, and expressions of Th17- and Treg-related cytokines were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Compared to patients without POAF, the CRP level and peripheral circulating Th17 cell were significantly increased in POAF patients. Th17/Treg ratio was positively correlated with CRP level, LA volume, CHADS₂ score, and CHA₂DS₂-VASc score. The areas under the receiver-operating characteristic (AUC) curves of Th17/Treg ratio for predicting POAF occurrence was higher than that of CRP level, LA volume, CHADS₂ score and CHA₂DS₂-VASc score. Th17/Treg ratio combined with CRP level has the highest AUC and a greater balance between sensitivity and specificity for predicting POAF.

CONCLUSIONS

Our data suggest that a Th17/Treg imbalance due to a Th17 shift, representing a pro-inflammatory tendency, participates in the development of POAF. Combining the Th17/Treg ratio with CRP level may provide a more accurate, sensitive, and specific indicator for prediction of POAF.

Prognostic factors of atrial fibrillation following coronary artery bypass graft surgery

OBJECTIVE

Postoperative atrial fibrillation (POAF) is the most common complication after cardiac surgery. To prevent this complication, routine pharmacological prophylactic drugs could be administered. Our study aimed to analyze the various perioperative factors associated with the development of POAF after coronary artery bypass graft (CABG) surgery.

METHODS

This prospective study included 617 patients, who received CABG surgery in the year 2014.

RESULTS

There were 429 (69.5%) male and 188 (30.5%) female patients. Mean patient age was 67.2 (9.4) years, and 365 patients (59.2%) were more than 65 years. Incidence of POAF was 24.1% (N = 149). Multivariable analysis showed that independent predictors of POAF after CABG surgery were: age >65 (P  = 0.008; OR 2.089; 95% CI 1.208-3.613), AF in the past (P < 0.001; OR 10.838; 95% CI 5.28-22.247), preoperative hypertrophy or dilation of left atrium (P = 0.002; OR 4.996; 95% CI 1.823-13.691), CABG surgery using 4 or more bypass grafts (P = 0.042; OR 1.669; 95% CI 0.972-2.866), preoperative hypokalemia (P = 0.001; OR 3.317; 95% CI 1.678-6.559), >trivial mitral (P = 0.024; OR 7.556; 95% CI 0.964-20.376), and aortic (P = 0.009; OR 1.937; 95% CI 1.178-3.187) valve regurgitation.

CONCLUSIONS

The profile of patients affected by POAF was considerably different with regard to the demographics, preoperative heart condition, history of previous heart rhythm disorders, and operative data. The most important independent factors that predicted POAF after CABG surgery were associated with structural heart defects, advanced age, history of previous AF, and preoperative hypokalemia.

Factors influencing postoperative atrial fibrillation in patients undergoing on-pump coronary artery bypass grafting, single center experience

BACKGROUND

The reported incidence of AF after CABG surgery varies from 20 to 40%, with the arrhythmia usually occurring between second and fourth postoperative days. Postoperative AF after CABG was associated with greater in-hospital mortality and worse survival at long-term follow-up. Therefore, intensive attention has focused on the prevention of AF in high-risk patients. Many perioperative factors have been suggested to increase the incidence of postoperative AF after conventional CABG. In this study we are trying to examine some of these risk factors as predictors for Post-operative AF in our patients. In this study, our aim was to identify the perioperative predictors of AF in our patients who underwent Coronary Artery Bypass Grafting.

METHODS

Our Patients were divided into two groups; Group A included patients who did not develop PO AF (168 patients) and Group B patients who developed PO AF (84 patients). Perioperative Data, including gender, age, demographic variables and postoperative morbidity and mortality were extracted from the medical records.

RESULTS

This retrospective cohort study was conducted on 252 consecutive adult patients underwent CABG, in King Faisal Specialist Hospital and Research Center in Jeddah, Saudi Arabia. The mean age for patients with PO AF was 65 years (P = .0001). Eight-three patients (49.4%) were diabetics in group A and 56 patients (66.7%) in group B (P = .0001). Patients who developed POAF had a lower ejection fraction (44.8 ± 5.7%) (P = .0001), diastolic dysfunction (P = .0001), Larger Left atrial volume (P = .0001). Bleeding requiring re-opening for exploration and Postoperative shock were identified as significant predictors for POAF. Multivariate logistic regression (odds ratio, ±95% CI, P value) was performed to identify the effect of age, preoperative heart rate, ejection fraction, postoperative bleeding, Shock, ventilator time, Sensitivity was 89.5%, specificity was 94.6%, positive predictive value was 89.5%, and negative predictive value was 94.6%.

CONCLUSION

In our study, advanced age, enlarged LA volume, low ejection fraction, combined surgeries and prolonged ventilation time were found to be predictors of atrial fibrillations after coronary artery bypass grafting.

Plasma Catecholamine Levels on the Morning of Surgery Predict Post-Operative Atrial Fibrillation

OBJECTIVES

This study sought to determine whether plasma catecholamines and monoamine oxidase-B (MOA-B) are associated with post-operative atrial fibrillation (POAF) in patients undergoing elective cardiac surgery.

BACKGROUND

Although intra- and post-operative adrenergic tone has been demonstrated to be an causative factor for POAF, the role and association of pre-operative plasma catecholamines remains unclear.

METHODS

Prior to administration of anesthesia on the morning of surgery, blood samples were obtained from 324 patients undergoing nonemergent coronary artery bypass graft and/or aortic valve surgery with cardiopulmonary bypass at East Carolina Heart Institute. The concentrations of norepinephrine (NE), dopamine (DA), epinephrine (EPI), and enzyme MAO-B were assessed in platelet-rich plasma. A log-binomial regression model was used to determine the association between quartiles of these variables and POAF.

RESULTS

Levels of NE (p = 0.0006) and EPI (p = 0.047) in the 4th quartile [Formula: see text] were positively associated with POAF, whereas DA (p = 0.0034) levels in the 4th quartile [Formula: see text] were inversely associated with POAF. Adjusting for age, heart failure (HF), and history of atrial fibrillation, the composite pre-operative (adrenergic) plasma marker [Formula: see text] was associated with a 4-fold increased occurrence of POAF (adjusted p = 0.0001). No association between plasma MAO-B and POAF was observed.

CONCLUSIONS

Our results suggest that pre-operative adrenergic tone is an important factor underlying POAF. This information provides evidence that assessment of plasma catecholamines may be a low-cost method that is easy to implement for predicting which patients are likely to develop POAF. More investigation in a multicentric setting is needed to validate our results.

Incidence, Predictors, and Outcomes of Early Atrial Arrhythmias After Lung Transplant: A Systematic Review and Meta-Analysis

OBJECTIVES

This study sought to determine the incidence, predictors, and prognostic implications of early post-lung transplant atrial arrhythmias (AAs).

BACKGROUND

Although frequently encountered, the prognostic implications of early AAs after lung transplant remain uncertain.

METHODS

A systematic review of MEDLINE and the Cochrane Library was conducted for all studies that reported early post-lung transplant AAs. Random-effects DerSimonian-Laird risk ratios (RRs) were calculated for categorical variables and standardized mean difference (SMD) for continuous variables.

RESULTS

A total of 12 studies with 3,203 patients (mean age 57 ± 3 years; 52% males) were included. The incidence of early post-lung transplant AAs during hospitalization was 26.6% at mean follow-up duration of 6.7 days. Predictors of post-lung transplant AAs included advanced age (SMD: 0.50; 95% confidence interval [CI]: 0.35 to 0.64), male gender (RR: 1.37; 95% CI: 1.28 to 1.47), history of smoking (RR: 1.23; 95% CI: 1.05 to 1.46), hypertension (RR: 1.35; 95% CI: 1.13 to 1.59), hyperlipidemia (RR: 1.39; 95% CI: 1.18 to 1.63), coronary artery disease (RR: 1.40; 95% CI: 1.12 to 1.7), left atrial diameter (SMD: 0.25; 95% CI: 0.07 to 0.44), and restrictive lung disease (RR: 1.34; 95% CI: 1.13 to 1.59). Post-lung transplant AAs were associated with increased all-cause mortality (adjusted RR: 1.63; 95% CI: 1.22 to 2.19) at mean follow-up of 27.8 months and length of hospital stay (36.5 ± 16.5 days vs. 26.1 ± 14.3 days; p < 0.001).

CONCLUSIONS

Early AAs post-lung transplant are associated with increased mortality and length of hospital stay. Advanced age, male sex, smoking, hypertension, hyperlipidemia, coronary artery disease, increased left atrial diameter, and restrictive lung disease are independent predictors of early AAs in post-lung transplant patients.

Cardiac Autonomic Dysfunction and Incidence of Atrial Fibrillation: Results From 20 Years Follow-Up

BACKGROUND

Cardiac autonomic perturbations frequently antecede onset of paroxysmal atrial fibrillation (AF). Interventions that influence autonomic inputs to myocardium may prevent AF. However, whether low heart rate or heart rate variability (HRV), which are noninvasive measures of cardiac autonomic dysfunction, are associated with AF incidence is unclear.

OBJECTIVES

This study sought to study the association between HRV and risk of AF.

METHODS

This study included 11,715 middle-aged adults in the ARIC (Atherosclerosis Risk In Communities) cohort with heart rate and HRV measures obtained from 2-min electrocardiogram recordings performed at baseline (1987 to 1989). These measures included SD of normal-to-normal RR intervals, high-frequency (HF) (0.15 to 0.40 Hz), low-frequency (0.04 to 0.15 Hz), and the low-frequency/HF ratio (denoting a greater sympathetic to parasympathetic dominance). Incident AF cases were ascertained by electrocardiogram at ARIC follow-up visits, hospital discharge diagnosis, or death certificates through 2011.

RESULTS

During an average follow-up of 19.4 years, 1,580 or 13.5% of participants developed AF. A baseline heart rate <60 beats/min was associated modestly with an increased risk of AF. Lower overall HRV as well as increased sympathetic/parasympathetic tone were associated independently with a higher risk of AF; the hazard ratio for each 1 SD lower SD of normal-to-normal RR intervals was 1.14 (95% confidence interval: 1.08 to 1.21), for HF was 1.12 (95% confidence interval: 1.06 to 1.17), and for low frequency/HF was 1.08 (95% confidence interval: 1.03 to 1.14).

CONCLUSIONS

Cardiac autonomic dysfunction denoted by low resting short-term HRV was associated with higher AF incidence. A low heart rate may be associated with higher AF risk. Further studies are needed to determine whether interventions in the general population to restore autonomic balance may prevent AF.

Perioperative Inotrope Therapy and Atrial Fibrillation Following Coronary Artery Bypass Graft Surgery: Evidence of a Racial Disparity

BACKGROUND AND OBJECTIVE

Following coronary artery bypass graft (CABG) surgery, mortality rates are significantly higher among black patients who experience postoperative atrial fibrillation (POAF). Perioperative inotropic therapy (PINOT) was associated with POAF in previous reports, but the extent to which race influences this association is unknown. In the present study, the relationship between PINOT, race, and POAF was examined in patients undergoing CABG surgery.

METHODS AND SETTING

Clinical records were examined from a prospectively maintained cohort of 11,855 patients (median age 64 yrs; 70% male; 16% black) undergoing primary isolated CABG at a large cardiovascular institute in the southeastern region of the United States. Relative risk (RR) and 95% confidence intervals (CIs) were computed using log-binomial regression.

MAIN RESULTS

The association between PINOT and POAF was significantly increased among black patients (adjusted RR 1.7, CI 1.4-2.0) compared with white patients (adjusted RR 1.3, CI 1.2-1.4) (p_interaction  = 0.013).

CONCLUSIONS

These findings suggest that PINOT may be disproportionately associated with POAF among black patients undergoing CABG surgery. Additional studies are needed to examine further the potential underlying mechanisms of this association.

Using nationwide ‘big data’ from linked electronic health records to help improve outcomes in cardiovascular diseases: 33 studies using methods from epidemiology, informatics, economics and social science in the ClinicAl disease research using LInked Bespoke studies and Electronic health Records (CALIBER) programme

Background

Electronic health records (EHRs), when linked across primary and secondary care and curated for research use, have the potential to improve our understanding of care quality and outcomes.

Objective

To evaluate new opportunities arising from linked EHRs for improving quality of care and outcomes for patients at risk of or with coronary disease across the patient journey.

Design

Epidemiological cohort, health informatics, health economics and ethnographic approaches were used.

Setting

230 NHS hospitals and 226 general practices in England and Wales.

Participants

Up to 2 million initially healthy adults, 100,000 people with stable coronary artery disease (SCAD) and up to 300,000 patients with acute coronary syndrome.

Main outcome measures

Quality of care, fatal and non-fatal cardiovascular disease (CVD) events.

Data platform and methods

We created a novel research platform [ClinicAl disease research using LInked Bespoke studies and Electronic health Records (CALIBER)] based on linkage of four major sources of EHR data in primary care and national registries. We carried out 33 complementary studies within the CALIBER framework. We developed a web-based clinical decision support system (CDSS) in hospital chest pain clinics. We established a novel consented prognostic clinical cohort of SCAD patients.

Results

CALIBER was successfully established as a valid research platform based on linked EHR data in nearly 2 million adults with > 600 EHR phenotypes implemented on the web portal (seehttps://caliberresearch.org/portal). Despite national guidance, key opportunities for investigation and treatment were missed across the patient journey, resulting in a worse prognosis for patients in the UK compared with patients in health systems in other countries. Our novel, contemporary, high-resolution studies showed heterogeneous associations for CVD risk factors across CVDs. The CDSS did not alter the decision-making behaviour of clinicians in chest pain clinics. Prognostic models using real-world data validly discriminated risk of death and events, and were used in cost-effectiveness decision models.

Conclusions

Emerging ‘big data’ opportunities arising from the linkage of records at different stages of a patient’s journey are vital to the generation of actionable insights into the diagnosis, risk stratification and cost-effective treatment of people at risk of, or with, CVD.

Future work

The vast majority of NHS data remain inaccessible to research and this hampers efforts to improve efficiency and quality of care and to drive innovation. We propose three priority directions for further research. First, there is an urgent need to ‘unlock’ more detailed data within hospitals for the scale of the UK’s 65 million population. Second, there is a need for scaled approaches to using EHRs to design and carry out trials, and interpret the implementation of trial results. Third, large-scale, disease agnostic genetic and biological collections linked to such EHRs are required in order to deliver precision medicine and to innovate discovery.

Study registration

CALIBER studies are registered as follows: study 2 – NCT01569139, study 4 – NCT02176174 and NCT01164371, study 5 – NCT01163513, studies 6 and 7 – NCT01804439, study 8 – NCT02285322, and studies 26–29 – NCT01162187. Optimising the Management of Angina is registered as Current Controlled Trials ISRCTN54381840.

Funding

The National Institute for Health Research (NIHR) Programme Grants for Applied Research programme (RP-PG-0407-10314) (all 33 studies) and additional funding from the Wellcome Trust (study 1), Medical Research Council Partnership grant (study 3), Servier (study 16), NIHR Research Methods Fellowship funding (study 19) and NIHR Research for Patient Benefit (study 33).

Cardiology: Post-Cardiothoracic Surgery Atrial Fibrillation: A Review of Preventive Strategies

Objective:

To review the available literature addressing preventive strategies of post-cardiothoracic surgery atrial fibrillation (post-CTS atrial fibrillation).

Data Sources:

Pertinent articles related to the etiology, risk factors, and preventive strategies were identified through a MEDLINE search (1966–March 2007) using the MeSH terms atrial fibrillation, cardiothoracic surgery, cardiac surgery, etiology, neurohormonal, sympathetic, volume, fluid, inflammation, risk factors, operative, pacing, β-adrenergic blockers, amiodarone, sotalol, calcium-channel blockers, magnesium, HMG-CoA reductase inhibitors, statins, fatty acids, PUFA, steroids, and nonsteroidal antiinflammatory drugs.

Study Selection and Data Extraction:

Articles evaluated were limited to human studies, published in the English language, with a Jadad score greater than 3. References of identified articles were reviewed for additional pertinent articles.

Data Synthesis:

Post-CTS atrial fibrillation most commonly occurs on the second or third postoperative day, with an incidence of 20–50%. Etiology theories include neurohormonal activation, volume overload, and inflammation. Studies examining nonpharmacologic therapies have shown that maintenance of the anterior epicardial fat pad is not a viable prophylactic strategy. Biatrial cardiac pacing, especially in combination with amiodarone, is a viable preventive option. Withdrawal of preoperative β-blockers places patients at higher risk for atrial fibrillation; these drugs should be continued postoperatively. Evidence exists supporting the use of amiodarone, sotalol, and magnesium in addition to β-blockers. Since most of these strategies work by attenuating neurohormonal activation, adverse events, including hypotension and bradycardia, are of concern. Adding agents with antiinflammatory properties, including hydroxymethylglutaryl coenzyme A reductase inhibitors or corticosteroids, may prove to be of benefit. Additional studies using novel therapies are needed in addition to established preventive strategies.

Conclusions:

Available evidence supports the continuation of preoperative β-blockers, as well as prophylactic amiodarone, sotalol, and magnesium. Other novel therapies, mostly targeting inflammation, are under investigation and may provide additional strategies.

Severe Cardiac Autonomic Derangement and Altered Ventricular Repolarization Pave the Way to Postoperative Atrial Fibrillation

OBJECTIVE

Postoperative atrial fibrillation (POAF) is a frequent complication after heart surgery. It has been shown that cardiac autonomic derangement plays a significant role in the genesis of atrial fibrillation (AF) and that AF might also be promoted by altered repolarization. Thus, the aim of our study was to determine the levels of cardiac autonomic modulation and repolarization properties in patients developing POAF.

METHODS

Seventy-nine patients scheduled for aortic and/or coronary artery bypass grafting surgery with cardiopulmonary bypass were enrolled prospectively. High-resolution 20-minute electrocardiogram recordings were obtained day before surgery to determine P, PR, QT, and QTc intervals, as well as linear (time and frequency domain) and nonlinear heart rate variability parameters (fractal dimension and detrended fluctuation analysis). QTc interval was calculated using Framingham correction.

RESULTS

Twenty-nine patients developed POAF (AF group), and 50 did not (non-AF group). Groups were similar regarding demographics, surgery type, and perioperative characteristics, except for older age in the AF group. QT and QTc intervals (Framingham) were longer in the AF group [442 (44) vs 422 (28) milliseconds, P = 0.018; and 448 (44) vs 431 (24) milliseconds, P = 0.031 and P = 0.019, respectively]. Time domain heart rate variability parameter PNN50 (percentage of pairs of adjacent NN intervals differing >50 milliseconds) was higher [14% (21%) vs 8% (16%), P = 0.015], and nonlinear parameter detrended fluctuation analysis α2 was lower in the AF group [0.81 (0.21) vs 0.91 (0.20), P = 0.031].

CONCLUSIONS

Profound cardiac autonomic derangement, suggestive of parasympathetic excessive modulation, exists preoperatively in patients inclined to POAF after cardiac surgery, whereby parameters PNN50 and α2 differentiated the AF from the non-AF group. Prolonged QTc intervals are associated with an increased risk of POAF.

Predictors of Atrial Fibrillation After Coronary Artery Bypass Grafting: A Bayesian Analysis

BACKGROUND

This study was conducted to identify preoperative predictors of postoperative atrial fibrillation (POAF) after isolated coronary artery bypass grafting (CABG) by using a Bayesian analysis that included information from prior studies.

METHODS

We performed a prospective observational study from October 2008 to December 2013 of 1,481 patients who underwent isolated CABG with cardiopulmonary bypass and had no history of AF. Bayesian analysis was used to study the preoperative risks factors for POAF.

RESULTS

The POAF incidence was 21%. Multivariate analysis identified the following independent predictors of POAF after CABG: high CHA₂DS₂-VASc (Congestive heart failure, Hypertension [blood pressure >140/90 mm Hg or treated hypertension on medication], Age ≥75 years, Diabetes mellitus, prior Stroke or transient ischemic attack or thromboembolism, vascular disease, Age 65 to 74 years, Sex category [female sex]) score (odds ratio [OR], 1.23; 95% credible interval [CI], 1.14 to 1.33 per 1-point increment, probability (Pr) [OR > 1] = 1), severe obesity with a body mass index of 35 kg/m² or higher (OR, 1.28; 95% CI, 1.12 to 1.45; Pr [OR > 1] = 1), preoperative β-blocker use (OR, 1.12; 95% CI, 1.06 to 1.20; Pr [OR > 1] = 1), preoperative antiplatelet therapy (OR, 1.75; 95% CI, 1.14 to 2.79, Pr [OR > 1] = 1), and renal insufficiency with a creatinine clearance of less than 60 mL/min (OR, 1.34; 95% CI, 1.03 to 1.74; Pr [OR > 1] = 1).

CONCLUSIONS

This prospective Bayesian analysis identified five independent preoperative predictors of POAF after isolated CABG with cardiopulmonary bypass: CHA₂DS₂-VASc score, severe obesity, preoperative β-blocker use, preoperative antiplatelet therapy, and renal failure. The main interest in the CHA₂DS₂-VASc score as a predictor of POAF is that it is a simple and widely used bedside tool. Patients with these independent predictors of POAF may constitute a target population to test preventive strategies, such as non-antiarrhythmic and antiarrhythmic drugs.

Atrial Fibrillation After Cardiac Surgery: Pathophysiology and Treatment

Atrial fibrillation (AF) occurs in 25% to 60% of patients after cardiac surgery. It is most consistently associated with advanced age and valvular heart operations. Despite improving knowledge of the pathophysiology of chronic AF, postoperative AF remains an obstinate clinical problem. It is associated with an increased risk of stroke, longer hospital stay, and higher hospital expenditure. Consequently, there has been great interest in strategies to prevent and treat this arrhythmia. Treatment for postoperative AF may require immediate electrical cardioversion for hemodynamically unstable patients. Heart rate control is useful in most patients, with anticoagulation considered after 48 hours. Antiarrhythmic therapy is often effective in restoring sinus rhythm but its use needs to be balanced against the patient's risk of proarrhythmic side effects such as torsade de pointes.

Variable use of amiodarone is associated with a greater risk of recurrence of atrial fibrillation in the critically ill

Background

Atrial fibrillation is a common rhythm disturbance in the general medical-surgical intensive care unit. Amiodarone is a popular drug in this setting but evidence to inform clinical practice remains scarce. We aimed to identify whether variation in the clinical use of amiodarone was associated with recurrent atrial fibrillation.

Methods

This was a retrospective audit of 177 critically ill patients who developed new-onset atrial fibrillation after admission to a tertiary level medical-surgical trauma intensive care unit. Patterns of amiodarone prescription (including dosage schedule and duration) were assessed in relation to recurrence of atrial fibrillation during the intensive care unit stay. Known recurrence risk factors, such as inotrope administration, cardiac disease indices, Charlson Comorbidity Index, magnesium concentrations, fluid balance, and potassium concentrations, were also included in adjusted analysis using forward stepwise logistic regression modelling.

Results

The cohort had a median (interquartile range) age of 69 years (60–75), Acute Physiology and Chronic Health Evalution II score of 22 (17–28) and Charlson Comorbidity Index of 2 (1–4). A bolus dose of amiodarone followed by infusion (P = 0.02), in addition to continuing amiodarone infusion through to discharge from the intensive care unit (P < 0.001), were associated with less recurrent dysrhythmia. Recurrence after successful treatment was associated with ceasing amiodarone while an inotrope infusion continued (P < 0.001), and was more common in patients with a prior history of congestive cardiac failure (P = 0.04), and a diagnosis of systemic inflammatory response syndrome (P = 0.02).

Conclusions

Amiodarone should be administered as a bolus dose followed immediately with an infusion when treating atrial fibrillation in the medical-surgical intensive care unit. Consideration should be given to continuing amiodarone infusions in patients on inotropes until they are ceased.