Atrial fibrillation: An anesthesiologist's perspective

Atrial fibrillation (AF) is not only the most common arrhythmia in the global population but also the most frequent one encountered in the operating room. For an anesthesiologist, it is crucial to have the ability to maintain hemodynamics and prevent complications of patients who present AF perioperatively. Here we provide a brief review in the novel concept of the classification, pathophysiology, and management of AF to provide a practical approach for physicians coming across this arrhythmia during the perioperative period.     

Potentially modifiable risk factors for atrial fibrillation following lung resection surgery: a retrospective cohort study

Atrial fibrillation is the most frequent arrhythmia after thoracic surgery and is associated with increased hospital costs, morbidity and mortality. In this study, we aimed to identify potentially modifiable risk factors for postoperative atrial fibrillation following lung resection surgery and to suggest possible measures to reduce risk. We retrospectively reviewed the medical records of 4731 patients who underwent lobectomy or more major lung resection over a 6‐year period. Patients who developed atrial fibrillation postoperatively and required treatment were included in the postoperative atrial fibrillation group, while the remaining patients were assigned to the non‐postoperative atrial fibrillation group. Risk factors for postoperative atrial fibrillation were analysed by multivariate analysis and propensity score matching. Overall, 12% of patients developed postoperative atrial fibrillation. Potentially modifiable risk factors for postoperative atrial fibrillation were excessive alcohol consumption (odds ratio (OR) = 1.48, 95% CI 1.08–2.02, p = 0.0140), red cell transfusion (2.70(2.13–3.43), p < 0.0001), use of inotropes (1.81(1.42–2.31), p < 0.0001) and open (vs. thoracoscopic) surgery (1.59(1.23–2.05), p < 0.0001). Compared with inotrope use, vasopressor administration was not related to postoperative atrial fibrillation. Use of steroids or thoracic epidural anaesthesia did not reduce the incidence of postoperative atrial fibrillation. We conclude that high alcohol consumption, red cell transfusion, use of inotropes and open surgery are potentially modifiable risk factors for postoperative atrial fibrillation. Pre‐operative alcohol consumption needs to be addressed. Avoiding red cell transfusion and performing lung resection via video‐assisted thoracoscopic surgery may reduce the incidence of postoperative atrial fibrillation and the administration of vasopressors rather than inotropes is preferred.     

Atrial fibrillation and bisphosphonate therapy

Bisphosphonates are the most commonly used treatment for osteoporosis and have proven efficacy in the reduction of vertebral and nonvertebral fractures. Recently, concerns have been raised about a possible association between bisphosphonate therapy and atrial fibrillation (AF) following the report of a significant increase in risk of serious AF in women treated with zoledronic acid in the HORIZON study. Subsequent studies have produced conflicting results but have not excluded the possibility of such an association. Currently there is no direct evidence that bisphosphonates exert either acute or chronic effects on cardiac electrophysiology. Nevertheless, altered intracellular electrolyte homeostasis and proinflammatory, profibrotic, and antiangiogenic effects provide potential mechanisms by which atrial conduction could be affected in patients treated with bisphosphonates. In studies in which an increase in risk of AF has been identified, there is no evidence that this translates into increased mortality or increased risk of stroke, and the risk‐benefit balance of bisphosphonate therapy in patients with osteoporosis and other forms of metabolic bone disease remains strongly positive. © 2010 American Society for Bone and Mineral Research     

Predicting the risk of atrial fibrillation after coronary artery bypass surgery

Atrial fibrillation (AF) is the most common arrhythmia, with an incidence of 17–33%, after coronary artery bypass grafting (CABG) and it increases the cost of operative treatment. β‐Blocker therapy reduces markedly the incidence of postoperative AF. The more effective preventive methods, e.g. amiodarone therapy or atrial pacing, are not cost‐effective for all the patients. Thus, identification of patients at high risk of AF after CABG would be helpful. This review summarizes the predictors of postoperative AF and the current methods for risk stratification. In summary, identification of the patients at high risk of postoperative AF remains a challenge. The clinical usefulness of most of the conventional factors, e.g. age or history of AF, is low. Even attempts to build logistic regression models based on the pre‐ and intraoperative variables have failed to provide powerful predictors for postoperative AF after CABG. From the new predictors, the P‐wave duration in signal‐averaged ECG looks promising. Sensitivity and negative predictive value are high, positive predictive value remains low, which limits its usefulness. Contrary, even detailed analysis of standard 12‐lead ECG or measure of heart rate variability has failed to provide useful information for risk stratification. A new method for risk stratification has been developed in our centre. The diagnostic accuracy of high‐rate atrial pacing seems to be sufficient to identify a group of patients to whom prophylactic treatment could be proactively targeted. Further experience is, however, warranted to verify significance of this method in everyday clinical practice.     

In-hospital acute kidney injury and atrial fibrillation: incidence,risk factors,and outcome

BackgroundThe incidence and the risk factors of in-hospitalized acute kidney injury (AKI) in patients hospitalized for atrial fibrillation (AF) were unclear.MethodsThe Improving Care for Cardiovascular Disease in China-AF (CCC-AF) project is an ongoing registry and quality improvement project, with 240 hospitals recruited across China. We selected 4527 patients hospitalized for AF registered in the CCC-AF from January 2015 to January 2019. Patients were divided into the AKI and non-AKI groups according to the changes in serum creatinine levels during hospitalization.ResultsAmong the 4527 patients, the incidence of AKI was 8.0% (361/4527). Multivariate logistic analysis results indicated that the incidence of in-hospital AKI in patients with AF on admission was 2.6 times higher than that in patients with sinus rhythm (OR 2.60, 95% CI 1.77–3.81). Age (per 10-year increase, OR 1.22, 95% CI 1.07–1.38), atrial flutter/atrial tachycardia on admission (OR 2.16, 95% CI 1.12–4.15), diuretics therapy before admission (OR 1.48, 95% CI 1.07–2.04) and baseline hemoglobin (per 20 g/L decrease, OR 1.21, 95% CI 1.10–1.32) were independent risk factors for in-hospital AKI. β blockers therapy given before admission (OR 0.67, 95% CI 0.51–0.87) and non-warfarin therapy during hospitalization (OR 0.71, 95% CI 0.53–0.96) were associated with a decreased risk of in-hospital AKI. After adjustment for confounders, in-hospital AKI was associated with a 34% increase in risk of major adverse cardiovascular (OR 1.34, 95% CI 1.02–1.90, p = 0.023).ConclusionsClinicians should pay attention to the monitoring and prevention of in-hospital AKI to improve the prognosis of patients with AF.     

Atrial fibrillation and biomarkers of myocardial fibrosis in heart failure

Objectives. Alterations of collagen metabolism present in heart failure promote the fibrotic substrate for the development of atrial fibrillation (AF). Myocardial collagen I synthesis and degradation can be assessed indirectly by circulating biomarkers such as the carboxy terminal propeptide (PICP) and carboxy-terminal telopeptide (CITP), respectively. Design. We examined myocardial collagen type-I metabolism in 143 patients with systolic heart failure (New York Heart Association Class 2–4) in relation to coexisting AF. Results. Mean age was 75 years, blood pressure 134/80 mm Hg, ejection fraction 34%, serum PICP 81 μg/L and CITP 8.3 μg/L, and median plasma brain natriuretic peptide 215 pg/L; 77 were in AF. PICP and CITP were related to left atrial diameter (r = 0.22, P = 0.013, and r = 0.26, P = 0.003) and CITP to pulmonary capillary wedge pressure and C-reactive protein (r = 0.19, P = 0.044, and r = 0.29, P = 0.003). A logistic regression suggested that PICP (odds ratio per 1 μg/L change 1.01, P = 0.012) and left ventricular end-diastolic volume (odds ratio per 1 mL change 0.98, P < 0.001) were independently associated with coexisting AF. Conclusion. Collagen type-I metabolism is associated to left atrial size. Heart failure patients with coexisting AF exhibit more altered collagen type-I metabolism than patients in sinus rhythm. This might represent more severe atrial and ventricular fibrosis.     

组蛋白去乙酰化酶：心房颤动治疗的潜在靶点

心房颤动是一种常见的心律失常,有很高的致残率和致死率,而目前心房颤动的治疗效果仍有限。研究发现,组蛋白去乙酰化酶(histone deacetylase,HDAC)在心血管疾病的病理生理中有着重要的作用,促进了心房颤动的发生。抑制HDAC可通过对心房重构的调控达到上游治疗的目的,成为一种新的治疗策略。本文就HDAC与心房颤动的研究进展作一综述。     

Perioperative magnesium supplementation to prevent atrial fibrillation after off-pump coronary artery surgery: a randomized controlled study

OBJECTIVE: Atrial fibrillation is a common complication after cardiac surgery. Magnesium is an effective and safe antiarrhythmic agent for arrhythmias that develop after cardiac surgery. The authors performed a study to evaluate the role of perioperative magnesium for prophylaxis of atrial fibrillation after off-pump coronary artery surgery. DESIGN: Randomized controlled study. SETTING: University teaching hospital. PARTICIPANTS: One hundred sixty consecutive patients undergoing elective, isolated, off-pump coronary artery bypass grafting were prospectively randomized into 2 groups. INTERVENTIONS: Patients in the magnesium group (n = 80) received a 2.5-g (20 mEq) magnesium sulphate infusion intraoperatively over 30 minutes, and the placebo group (n = 80) received normal saline solution. MEASUREMENTS AND MAIN RESULTS: Postoperative atrial fibrillation occurred in 16 of 80 patients (20%) in the magnesium group and in 18 of 80 (22.5%) in the placebo group (p = 0.9). CONCLUSION: The use of 2.5 g of intraoperative magnesium showed no effect in preventing atrial fibrillation after off-pump coronary artery bypass.     

Signal-averaged P wave duration and the long-term risk of permanent atrial fibrillation

Objective. To assess the long-term risk of developing permanent AF in relation to the signal-averaged P wave duration (SAPWD) and clinical and echocardiographic characteristics. Design. In an observational study design we studied 131 patients with earlier ECG-documented AF and successfully restored sinus rhythm attending a long-term, follow-up visit at hospital or at home. Established permanent AF was examined in relation to primary clinical, echocardiographic, and electrophysiological parameters. Results. Only prolonged SAPWD (p =0.006) was associated with an increased risk of development of permanent AF. The risk of permanent AF after 3 years follow-up was 0.72 with an SAPWD equal to 180 ms versus 0.39 with a normal SAPWD (130 ms). We found no prognostic effect of age, gender, dilated left atrium, long duration of AF history, or long duration of the most recent episode of AF. Co-existing hypertension reduced the risk of permanent AF; this could be explained by concomitant treatment with angiotensin-converting-enzyme-inhibitors. Conclusion. Prolonged SAPWD (a marker of atrial remodelling) appears to be a risk factor for long-term development of permanent AF.     

Anticoagulation strategy in patients with atrial fibrillation after carotid endarterectomy

Aim: Carotid artery stenosis and atrial fibrillation are diseases of the aging patient population. Literature lacks precise anticoagulation treatment protocols for patients with atrial fibrillation following carotid endarterectomy. We present our experiences with anticoagulation strategy in this particular patient population.

Patients and methods: Between June 2001–September 2017, 165 patients with chronic or paroxysmal atrial fibrillation out of 1594 cases from three different institutions whom received Coumadin and aspirin and required carotid endarterectomy were reviewed, respectively. Mean age was 63.4?±?7.9 years. Male/female ratio was 102/63. There were 67 diabetic and 138 hypertensive cases.

Results: Patients are followed a mean of 64.4?±?16.9 months. Early mortality occurred in two patients due to intracranial bleeding and heart failure. Another patient was lost due to intracerebral hemorrhage and 16 other patients died due to various causes in the late follow-up. Three patients required exploration against bleeding.

Conclusion: Combination of warfarin with an aim to keep the INR value between 2 and 3, and aspirin at a dosage of 100?mg per day seemed feasible and in our modest patient cohort. Further studies including multicenter larger data are warranted in order to establish a precise anticoagulation treatment protocol for patients with atrial fibrillation after carotid endarterectomy.     

Impact of minimal invasive extracorporeal circulation on atrial fibrillation after coronary artery bypass surgery

Postoperative atrial fibrillation (POAF) is the most common arrhythmia after cardiac surgery with an incidence between 15% and 50% and pathophysiology not fully known. By choosing the method of extracorporeal circulation with focus on the reduction of systemic inflammatory response, one can potentially decrease the risk of POAF. In this prospective, randomized trial, we compared minimal invasive extracorporeal circulation (MiECC) with conventional extracorporeal circulation (CECC) in the prevention of POAF after coronary artery bypass surgery (CABG). A total of 240 patients who were scheduled for their first on-pump CABG, were randomized to MiECC or CECC. The primary outcome measure was the incidence of first POAF during the first 84 hours after surgery. POAF occurred in 42/120 (35.0%) MiECC patients and 43/120 (35.8%) CECC patients with nonsignificant difference between the groups (OR 1.043, 95% CI 0.591-1.843, P = .884). The first postoperative creatine kinase-MB mass (CK-MBm) value was lower in the MiECC group, 13.95 [10.5-16.7] (median [IQR]) than in the CECC group, 15.30 [11.4-18.9] (P = .036), whereas the use of perioperative dobutamine was higher in the MiECC group, 18/120 (15.0%), than in the CECC group 8/120 (6.7%) (P = .038). The incidence of a stroke, perioperative myocardial infarction, and resternotomy caused by bleeding did not differ in the MiECC and CECC groups. Age (OR 1.08, 95% CI 1.04-1.13, P = .000) and peak postoperative CK-MBm (OR 1.57, 95% CI 1.06-2.37, P = .026) were independent predictors of POAF. MiECC compared to CECC was not effective in reducing the incidence of POAF in patients undergoing CABG.     

A Comparative Prospective Observational Study on the Use of Direct Oral Anticoagulants after Cardiac Surgery for the Management of Atrial Fibrillation

Purpose: Recently, guidelines recommended the use of direct oral anticoagulants (DOACs) for the management of non-valvular atrial fibrillation (NVAF). Postoperative atrial fibrillation (POAF) is the most common post-surgical complication of cardiac surgery, but the efficacy and safety of DOAC for POAF have rarely been investigated. We conducted a prospective observational study to investigate the efficacy and safety of DOAC administered immediately after POAF.Materials and Methods: In all, 135 patients that experienced POAF after cardiac surgery were treated with a DOAC. Primary endpoints were either bleeding or thromboembolic events. Secondary endpoints included changes in hemoglobin (Hb), prothrombin time (PT), activated partial thromboplastin time (APTT), serum creatinine (sCr), estimated glomerular filtration rate (eGFR), and pleural/pericardial effusion.Results: Patients were treated with apixaban (n = 31), edoxaban (n = 87), and rivaroxaban (n = 17). Major bleeding (p = 0.011) and gastrointestinal (GI) bleeding (p = 0.047) were significantly more frequent in the rivaroxaban group. Stroke was observed in one rivaroxaban group patient and none in the other two groups.Conclusion: DOAC as anticoagulation therapy for the early intervention of POAF following cardiac surgery is associated with a low incidence of major bleeding; a favorable safety profile and excellent efficacy were demonstrated for DOAC. Furthermore, our results indicate that the safety and efficacy of apixaban and edoxaban are better than rivaroxaban.     

Treatment of Postoperative New Onset Atrial Fibrillation with Repolarization Delaying Agents after Heart Surgery

Purpose: The aim of this study was to evaluate the efficacy of the multichannel-blocker dronedarone for postoperative new onset atrial fibrillation (POAF) as compared to amiodarone.Methods: Out of 990 patients who underwent cardiothoracic surgery between March 2011 and March 2012, 166 patients who developed POAF and treated with amiodarone or dronedarone were enrolled in this study.Results: Eighty-nine patients were treated with amiodarone and 77 patients were treated with dronedarone at discharge. Seventy-five percent of patients with dronedarone were treated initially with intravenous amiodarone but quickly converted to oral dronedarone as soon as the mechanical ventilation was weaned off. The rate of conversion in sinus rhythm was not influenced by the resulting amiodarone-to-dronedarone crossover as compared to oral dronedarone only (p <0.247 at the ICU and p <0.640 at the normal care unit). At hospital discharge sinus rhythm was documented in 44% of the amiodarone patients and 99% of the dronedarone patients (p <0.001). The maintenance of sinus rhythm was demonstrated in 82% of the amiodarone patients versus 81% of the dronedarone patients at 6-month follow-up (p <0.804).Conclusions: Our data demonstrated the higher conversion rate to sinus rhythm in the early phase in the dronedarone group despite a comparable conversion rate in the mid-term phase compared to amiodarone.     

Atrial fibrillation after surgical revascularization: is there any difference between on-pump and off-pump?

Objective: Postoperative atrial fibrillation (AF) is still frequent complication after cardiac surgery in spite of the improvements in the surgical procedures. There is still controversy whether or not, the absence of cardiopulmonary bypass results in a lower incidence of AF. Methods: Six hundered and seventy patients that underwent revascularization by using in situ LIMA for single vessel disease were included in this retrospective study and the patients were divided in two groups. Group I included 328 patients who underwent complete revascularization with cardiopulmonary bypass and group II consisted of 342 patients who underwent complete revascularization without cardiopulmonary bypass. Then, the incidence and predictive perioperative factors of AF in two groups were determined and compared with each other. Results: There were no significant differences between two groups with respect to the preoperative demographic characteristics of the patients. The incidence of postoperative AF was determined as 16.1% after on-pump and 14.6% after off-pump revascularization. Avoiding cardiopulmonary bypass did not decrease the incidence of postoperative AF. Sex, age over 65 years, prophylactic β-blocker usage and left ventricular dysfunction were independent predictive factors in group I (r²=0.51; P<0.001). However, only age over 65 years and prophylactic β-blocker usage were independent predictive factors in group II (r²=0.59; P<0.01). The rates of AF in both groups were decreased by using prophylactic β-blocker usage (P=0.05 in group I, P<0.001 in group II). Conclusions: There is no reduction of AF rate in myocardial revascularization without cardiopulmonary bypass. However, prophylactic β-blocker usage decreases the incidence of AF after both on-pump and off-pump myocardial revascularization.