Analysis of risk factors for development of atrial fibrillation early after cardiac valvular surgery

Validity of a smartwatch for detecting atrial fibrillation in patients after heart valve surgery: a prospective observational study

OBJECTIVES

Atrial fibrillation (AF) is a common early arrhythmia after heart valve surgery that limits physical activity. We aimed to evaluate the criterion validity of the Apple Watch Series 5 single-lead electrocardiogram (ECG) for detecting AF in patients after heart valve surgery.

DESIGN

We enrolled 105 patients from the University Hospital of North Norway, of whom 93 completed the study. All patients underwent single-lead ECG using the smartwatch three times or more daily on the second to third or third to fourth postoperative day. These results were compared with continuous 2-4 days ECG telemetry monitoring and a 12-lead ECG on the third postoperative day.

RESULTS

On comparing the Apple Watch ECGs with the ECG monitoring, the sensitivity and specificity to detect AF were 91% (75, 100) and 96% (91, 99), respectively. The accuracy was 95% (91, 99). On comparing Apple Watch ECG with a 12-lead ECG, the sensitivity was 71% (62, 100) and the specificity was 92% (92, 100).

CONCLUSION

The Apple smartwatch single-lead ECG has high sensitivity and specificity, and might be a useful tool for detecting AF in patients after heart valve surgery.

Postoperative Atrial Fibrillation: A Review

Atrial fibrillation (AF) in the postoperative phase is a manifestation of numerous factors, including surgical stress, anesthetic effects, and underlying cardiovascular conditions. The resultant cardiac hyperactivity can induce new onset or exacerbate existing AF. A common phenomenon, postoperative atrial fibrillation (POAF) affects nearly 40% of patients and is associated with longer hospitalization stays, and increased mortality, heart failure, stroke, and healthcare costs. Areas of controversy in POAF include whether to anticoagulate patients who have short-lived POAF, especially given their higher bleeding risk in the postoperative period, and the identification of patients who would benefit the most from preventive drug therapy for POAF. This review discusses the pathophysiology and management of POAF, and strategies to reduce its occurrence.

Intraoperative Dexmedetomidine Use for Enhanced Recovery after Surgery (ERAS) in Cardiac Surgery-Single Center Retrospective Observational Cohort Study

Background and Objectives: Dexmedetomidine, an alpha-2 agonist, is used as an adjunct to anesthesia in enhanced recovery after surgery (ERAS) programs. One of its advantages is the opioid-sparing effect which can facilitate early extubation and recovery. When the ERAS cardiac society was set in 2017, our facility was already using the ERAS program, in which the "fast-track Anesthesia" was facilitated by the intraoperative infusion of dexmedetomidine. Our objective is to share our experience and investigate the potential impact of intraoperative dexmedetomidine use as a part of the ERAS program on patient outcomes in elective cardiac surgery. Materials and Methods: An observational retrospective cohort study was conducted at a university hospital in Switzerland. The patients who underwent elective cardiac surgery with cardiopulmonary bypass between 1 June 2017 and 31 August 2018 were included in this analysis (n = 327). Regardless of the surgery type, all the patients received a standardized fast-track anesthesia protocol inclusive of dexmedetomidine infusion, reduced opioid dose, and parasternal nerve block. The primary outcome was the postoperative time when the criteria for extubation were met. Three groups were identified: group 0-(extubated in the operating room), group < 6 (extubated in less than 6 h), and group > 6 (extubated in >6 h). The secondary outcomes were adverse events, length of stay in ICU and in hospital, and total hospitalization costs. Results: Dexmedetomidine was well-tolerated, with no significant adverse events reported. Early extubation was performed in 187 patients (57%). Group 3 had a significantly longer length of stay in the ICU (median: 70 h vs. 25 h) and in hospital (17 vs. 12 days), and consequently higher total hospitalization costs (CHF 62,551 vs. 38,433) compared to the net data from the other two groups (p < 0.0001). Conclusions: Our findings suggest that dexmedetomidine can be safely used as part of the opioid-sparing anesthesia protocol in patients undergoing elective cardiac surgery with cardiopulmonary bypass with the potential to facilitate early extubation, shorter ICU and hospital stays, and reduced hospitalization costs.

Prevention of Atrial Fibrillation After Cardiac Surgery: A Review of Literature and Comparison of Different Treatment Modalities

Atrial fibrillation is the most common arrhythmia to occur after cardiac surgery, with an incidence of 10% to 50%. It is associated with postoperative complications including increased risk of stroke, prolonged hospital stays and increased costs. Despite new insights into the mechanisms of atrial fibrillation, no specific etiologic factor has been identified as the sole perpetrator of the arrhythmia. Current evidence suggests that the pathophysiology of atrial fibrillation in general, as well as after cardiac surgery, is multifactorial. Studies have also shown that new-onset postoperative atrial fibrillation following cardiac surgery is associated with a higher risk of short-term and long-term mortality. Furthermore, it has been demonstrated that prophylactic medical therapy decreases the incidence of postoperative atrial fibrillation after cardiac surgery. Of note, the incidence of postoperative atrial fibrillation has not changed during the last decades despite the numerous preventive strategies and operative techniques proposed, although the perioperative and postoperative care of cardiac patients as such has improved.

Acupuncture after valve surgery is feasible and shows promise in reducing postoperative atrial fibrillation: The ACU-Heart pilot trial

Objective

Acupuncture is an effective treatment for arrythmias and postoperative symptoms but has not been investigated after cardiac surgery. Acupuncture After Heart Surgery is a prospective, randomized, controlled pilot trial of daily inpatient acupuncture or standard care after valve surgery with the primary end point being feasibility and secondary end points being reduction in postoperative atrial fibrillation incidence and postoperative symptoms.

Methods

A total of 100 patients without a history of atrial fibrillation underwent primary valve surgery via sternotomy and randomized 1:1 to acupuncture (51) or standard care (49). The acupuncture group received daily inpatient sessions starting on postoperative day 1. Postoperative symptoms (pain, nausea, stress, anxiety) were assessed once daily in the standard care group and before/after daily intervention in the acupuncture group. The groups were comparable except for age (acupuncture: 55.6 ± 11.4 years, standard care: 61.0 ± 9.3 years; P = .01).

Results

The Acupuncture After Heart Surgery pilot trial met primary and secondary end points. There were no adverse events. An average of 3.8 (±1.1) acupuncture sessions were delivered per patient during a mean hospital stay of 4.6 days (±1.3). Acupuncture was associated with a reduction in pain, nausea, stress, and anxiety after each session (P < .0001), and patients receiving acupuncture had reduced postoperative stress and anxiety across admission compared with standard care (P = .049 and P = .036, respectively). Acupuncture was associated with reduced postoperative atrial fibrillation incidence (acupuncture: 7 [13.7%], standard care: 16 [32.7%]; P = .028), fewer discharges on amiodarone (acupuncture: 5 [9.8%], standard care: 13 [26.5%]; P = .03), and fewer hours in the intensive care unit (acupuncture: 30.3 ± 10.0, standard care: 37.0 ± 22.5; P = .057).

Conclusions

Acupuncture after valve surgery is feasible, is well tolerated, and has clinical benefit. The reduction noted in postoperative atrial fibrillation incidence will inform larger trials designed to further investigate the impact of acupuncture on postoperative atrial fibrillation and medical outcomes.

Apixaban for Anticoagulation After Robotic Mitral Valve Repair

BACKGROUND

There is no consensus regarding postoperative anticoagulation after mitral valve repair (MVRep). We compared the outcomes of post-MVRep anticoagulation with apixaban compared to warfarin.

METHODS

We reviewed data of 666 patients who underwent isolated robotic MVRep between January 2008 and October 2019. We excluded patients who had conversion to sternotomy and those discharged without anticoagulation or on clopidogrel (n = 40). Baseline and intraoperative characteristics and antiplatelet/anticoagulation records were collected. In-hospital and post-discharge complications and overall survival were compared.

RESULTS

Among the 626 studied patients the median age was 58 years (interquartile range, 51-66), 71% were male, and 1% (n = 9) had atrial fibrillation. Eighty percent (n = 499) were discharged on warfarin and 20% on apixaban (n = 127). Almost all patients (126 of 127, 99%) in the apixaban group were also on aspirin at discharge, whereas in the warfarin group only 79% (n = 395) were also on aspirin at discharge. Baseline characteristics were similar, except that the apixaban group had more female patients (46 of 127, 36% vs 136 of 499, 27%, P = .047). There were no differences in in-hospital complications, including stroke. Readmission rate was higher in the apixaban group (15 of 127, 12% vs 30 of 499, 6%, P = .02), driven mostly by postoperative atrial fibrillation (6 of 127 [5%] vs 5 of 499 [1%], respectively; P = .01). There was no difference in other complications (including bleeding and thromboembolic events), or overall mortality within 3 years. Exclusion of patients who did not receive aspirin at discharge did not affect the results.

CONCLUSIONS

Anticoagulation with apixaban after minimally invasive robotic MVRep is safe and has similar rates of bleeding and thromboembolism compared to patients treated with warfarin.

Statin and Postcardiac Surgery Atrial Fibrillation Prevention: A Systematic Review and Meta-Analysis

ABSTRACT

Postoperative atrial fibrillation (POAF) is a frequently reported postcardiac surgery complication leading to increased in-hospital and long-term mortality rates. Many randomized controlled trials (RCTs) have recently suggested using statins to protect against POAF. Therefore, we performed a systematic literature search and meta-analysis in electronic databases for eligible studies published between January 2006 and January 2022. The principal inclusion criteria were as follows: RCTs' study design, statin-naive patients, total study participants ≥50 units, and statin pretreatment started no more than 21 days before cardiac surgery. In the primary analysis, statin pretreatment reduced the incidence of POAF compared with placebo. Analyzing different molecules, atorvastatin was associated with lower incidence of POAF but rosuvastatin was not. We therefore performed a sensitivity analysis excluding RCTs affected by important risk of biases. Thus, studies whose participants were ≥199 were those eligible for the secondary analysis. No statistically significant difference between statin pretreatment and placebo (OR 0.87; 95% CI: 0.71-1.07, P = 0.18) as well as for atorvastatin (OR 0.88; 95% CI: 0.61-1.28; P = 0.48; I 2 = 84%) and rosuvastatin (OR 0.87; 95% CI: 0.68-1.12, P = 0.29) was observed. To conclude, statin pretreatment before cardiac surgery is not associated with a significant reduction in POAF occurrence.

Arrhythmias in Patients With Valvular Heart Disease: Gaps in Knowledge and the Way Forward

The prevalence of both organic valvular heart disease (VHD) and cardiac arrhythmias is high in the general population, and their coexistence is common. Both VHD and arrhythmias in the elderly lead to an elevated risk of hospitalization and use of health services. However, the relationships of the two conditions is not fully understood and our understanding of their coexistence in terms of contemporary management and prognosis is still limited. VHD-induced left ventricular dysfunction/hypertrophy and left atrial dilation lead to both atrial and ventricular arrhythmias. On the other hand, arrhythmias can be considered as an independent condition resulting from a coexisting ischemic or non-ischemic substrate or idiopathic ectopy. Both atrial and ventricular VHD-induced arrhythmias may contribute to clinical worsening and be a turning point in the natural history of VHD. Symptoms developed in patients with VHD are not specific and may be attributable to hemodynamical consequences of valve disease but also to other cardiac conditions including arrhythmias which are notably prevalent in this population. The issue how to distinguish symptoms related to VHD from those related to atrial fibrillation (AF) during decision making process remains challenging. Moreover, AF is a traditional limit of echocardiography and an important source of errors in assessment of the severity of VHD. Despite recent progress in understanding the pathophysiology and prognosis of postoperative AF, many questions remain regarding its prevention and management. Furthermore, life-threatening ventricular arrhythmias can predispose patients with VHD to sudden cardiac death. Evidence for a putative link between arrhythmias and outcome in VHD is growing but available data on targeted therapies for VHD-related arrhythmias, including monitoring and catheter ablation, is scarce. Despite growing evidences, more research focused on the prognosis and optimal management of VHD-related arrhythmias is still required. We aimed to review the current evidence and identify gaps in knowledge about the prevalence, prognostic considerations, and treatment of atrial and ventricular arrhythmias in common subtypes of organic VHD.

Atrial fibrillation post cardiac bypass surgery

Atrial fibrillation occurs in 5-40% patients after coronary artery bypass graft surgery. Atrial fibrillation increases mortality and morbidity in the post-operative period. We sought to conduct a comprehensive review of literature focusing on pathophysiology, risk factors, prevention and treatment of post coronary artery bypass graft atrial fibrillation.

Management of Atrial Fibrillation Following Cardiac Surgery: Observational Study and Development of a Standardized Protocol

BACKGROUND

Postoperative atrial fibrillation (POAF) is the most common complication occurring after cardiac surgery. Guidelines for the management of this complication are scarce, often resulting in differences in treatment strategy use among patients.

OBJECTIVE

To evaluate the management of POAF in a cardiac surgery department, characterize the extent of its variability, and develop a standardized protocol.

METHODS

This was an observational retrospective study with data from patients who underwent cardiac surgeries with subsequent POAF between January 1, 2017, and June 1, 2018. We assessed the difference in the proportions of patients whose first POAF episodes were treated with a rate control (RaC) strategy, a rhythm control (RhC) strategy, and both among different hospital units. We also assessed the mean duration of POAF episodes, POAF recurrences, and the management of anticoagulation.

RESULTS

Data from 97 patients were included in this study. The POAF management strategy differed significantly among the 3 types of hospital units (P = 0.001). Considering all POAF episodes (including all recurrences), 83 of the 97 patients (85.6%) received amiodarone as part of the RhC strategy. Anticoagulation was used in 58 (59.8%) patients and was suboptimal according to the study criteria in 29.5% of the patients included. Based on these results, a hospital working group developed a standardized protocol for POAF management.

CONCLUSIONS AND RELEVANCE

POAF management was heterogeneous at our institution. This article highlights the need for clear practice guidelines based on large prospective studies to provide care according to best practices.

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.

Atrial Fibrillation Post Coronary Artery Graft Surgery: A Review Of Literature

Atrial fibrillation (AF) is a failure that is observed in heart disease and is also known to be the most common heart rhythm disturbance post coronary artery bypass surgery. Although AF is considered a transient problem, it is usually accompanied with a variety of complications and morbidity for patients and may result in death. In the present study, pre- and post-operative considerable factors which may increase the risk and mortality of AF, and possible treatments have been concisely reviewed.

Antithrombotic therapy after mitral valve repair: VKA or aspirin?

The optimal antithrombotic therapy following mitral valve repair (MVr) is still a matter of debate. Therefore, we evaluated the rate of thromboembolic and bleeding complications of two antithrombotic prevention strategies: vitamin K antagonists (VKA) versus aspirin. Consecutive patients who underwent MVr between 2004 and 2016 at three Dutch hospitals were evaluated for thromboembolic and bleeding complications during three postoperative months. The primary endpoint was the combined incidence of thromboembolic and bleeding complications to determine the net clinical benefit of VKA strategy as compared with aspirin. Secondary objectives were to evaluate both thromboembolic and bleeding rates separately and to identify predictors for both complications. A total of 469 patients were analyzed, of whom 325 patients (69%) in the VKA group and 144 patients (31%) in the aspirin group. Three months postoperatively, the cumulative incidence of the combined end point of the study was 9.2% (95%CI 6.1-12) in the VKA group and 11% (95%CI 6.0-17) in the aspirin group [adjusted hazard ratio (HR) 1.6, 95%CI 0.83-3.1]. Moreover, no significant differences were observed in thromboembolic rates (adjusted HR 0.82, 95%CI 0.16-4.2) as well as in major bleeding rates (adjusted HR 1.89, 95%CI 0.90-3.9). VKA and aspirin therapy showed a similar event rate of 10% during 3 months after MVr in patients without prior history of AF. In both treatment groups thromboembolic event rate was low and major bleeding rates were comparable. Future prospective, randomized trials are warranted to corroborate our findings.

A retrospective study on atrial fibrillation after coronary artery bypass grafting surgery at The National Heart Institute, Kuala Lumpur

Background: Atrial fibrillation (AF) is common after cardiac surgery and has been associated with poor outcome and increased resource utilization. The main objective of this study is to determine the incidence of POAF in Malaysia and identify the predictors of developing POAF. The secondary outcome of this study would be to investigate the difference in mortality and morbidity rates and the duration of intensive care unit (ICU), high dependency unit (HDU) and hospital stay between the two. Methods: This is a retrospective single-center, cross sectional study conducted at the National Heart Institute, Malaysia. Medical records of 637 who underwent coronary artery bypass grafting (CABG) surgery in 2015 were accrued. Pre-operative, operative and post-operative information were subsequently collected on a pre-formulated data collection sheet. Data were then analyzed using IBM SPSS v23. Results: The incidence of POAF in our study stands at 28.7% with a mean onset of 45±33 hours post operatively. Variables with independent association with POAF include advancing age, Indian population, history of chronic kidney disease, left ventricular ejection fraction and beta-blocker treatment. The mortality rate is significantly higher statistically ( p < 0.05), and similarly the incidence of stroke. The incidence of other post-operative complications was also significantly higher statistically. The duration of ICU, HDU and hospital stays were statistically longer ( p < 0.001) with higher rates of ICU readmissions and reintubations seen. Conclusion: We conclude that the incidence of POAF in Malaysia is comparable to the figures in Western countries, making POAF one of the most commonly encountered condition after CABG with similar higher rates of mortality, poor outcomes and longer duration of stay, and therefore increased cost of care. Strategies to reduce the incidence of AF after cardiac surgery should favorably affect surgical outcomes and reduce utilization of resources and thus lower cost of care.

A retrospective study on atrial fibrillation after coronary artery bypass grafting surgery at The National Heart Institute, Kuala Lumpur

Background: Atrial fibrillation (AF) is common after cardiac surgery and has been associated with poor outcome and increased resource utilization. The main objective of this study is to determine the incidence of POAF in Malaysia and identify the predictors of developing POAF. The secondary outcome of this study would be to investigate the difference in mortality and morbidity rates and the duration of intensive care unit (ICU), high dependency unit (HDU) and hospital stay between the two. Methods: This is a retrospective single-center, cross sectional study conducted at the National Heart Institute, Malaysia. Medical records of 637 who underwent coronary artery bypass grafting (CABG) surgery in 2015 were accrued. Pre-operative, operative and post-operative information were subsequently collected on a pre-formulated data collection sheet. Data were then analyzed using IBM SPSS v23. Results: The incidence of POAF in our study stands at 28.7% with a mean onset of 45±33 hours post operatively. Variables with independent association with POAF include advancing age, Indian population, history of chronic kidney disease, left ventricular ejection fraction and beta-blocker treatment. The mortality rate is significantly higher statistically ( p < 0.05), and similarly the incidence of stroke. The incidence of other post-operative complications was also significantly higher statistically. The duration of ICU, HDU and hospital stays were statistically longer ( p < 0.001) with higher rates of ICU readmissions and reintubations seen. Conclusion: We conclude that the incidence of POAF in Malaysia is comparable to the figures in Western countries, making POAF one of the most commonly encountered condition after CABG with similar higher rates of mortality, poor outcomes and longer duration of stay, and therefore increased cost of care. Strategies to reduce the incidence of AF after cardiac surgery should favorably affect surgical outcomes and reduce utilization of resources and thus lower cost of care.

Clinical significance and risk factors for new onset and recurring atrial fibrillation following cardiac surgery - a retrospective data analysis

Background

Although mortality after cardiac surgery has significantly decreased in the last decade, patients still experience clinically relevant postoperative complications. Among others, atrial fibrillation (AF) is a common consequence of cardiac surgery, which is associated with prolonged hospitalization and increased mortality.

Methods

We retrospectively analyzed data from patients who underwent coronary artery bypass grafting, valve surgery or a combination of both at the University Hospital Muenster between April 2014 and July 2015. We evaluated the incidence of new onset and intermittent/permanent AF (patients with pre- and postoperative AF). Furthermore, we investigated the impact of postoperative AF on clinical outcomes and evaluated potential risk factors.

Results

In total, 999 patients were included in the analysis. New onset AF occurred in 24.9% of the patients and the incidence of intermittent/permanent AF was 59.5%. Both types of postoperative AF were associated with prolonged ICU length of stay (median increase approx. 2 days) and duration of mechanical ventilation (median increase 1 h). Additionally, new onset AF patients had a higher rate of dialysis and hospital mortality and more positive fluid balance on the day of surgery and postoperative days 1 and 2. In a multiple logistic regression model, advanced age (odds ratio (OR) = 1.448 per decade increase, p < 0.0001), a combination of CABG and valve surgery (OR = 1.711, p = 0.047), higher C-reactive protein (OR = 1.06 per unit increase, p < 0.0001) and creatinine plasma concentration (OR = 1.287 per unit increase, p = 0.032) significantly predicted new onset AF. Higher Horowitz index values were associated with a reduced risk (OR = 0.996 per unit increase, p = 0.012). In a separate model, higher plasma creatinine concentration (OR = 2.125 per unit increase, p = 0.022) was a significant risk factor for intermittent/permanent AF whereas higher plasma phosphate concentration (OR = 0.522 per unit increase, p = 0.003) indicated reduced occurrence of this arrhythmia.

Conclusions

New onset and intermittent/permanent AF are associated with adverse clinical outcomes of elective cardiac surgery patients. Different risk factors implicated in postoperative AF suggest different mechanisms might be involved in its pathogenesis. Customized clinical management protocols seem to be warranted for a higher success rate of prevention and treatment of postoperative AF.

Electronic supplementary material

The online version of this article (10.1186/s12871-017-0455-7) contains supplementary material, which is available to authorized users.

[Bayes' syndrome in cardiac surgery: prevalence of interatrial block in patients younger than 65 years undergoing cardiac surgery and association with postoperative atrial fibrillation]

OBJECTIVE

Interatrial block (IAB) is a well-known entity that is associated with an increased risk of atrial fibrillation (AF). This association is called Bayes' syndrome. The aim of our study was to define the prevalence of IAB among patients younger than 65 years undergoing cardiac surgery and determine whether there is an association between the presence of interatrial conduction delay and postoperative atrial fibrillation (POAF).

METHOD

A total of 207 patients were enrolled. Partial IAB was defined as P-wave>120ms. Advanced IAB was defined as P-wave>120ms+biphasic morphology in the inferior leads. Ocurrence of POAF was assessed and a comparative analysis was conducted between patients that did and did not develop AF.

RESULTS

IAB prevalence was 78.3% (partial 66.2%, advanced 12.1%). POAF occurred in 28.5% of all patients, and was more frequent among patients with advanced IAB (44%) compared to 27.7% and 24.4% of POAF among patients with partial IAB and without IAB, respectively. Patients who developed POAF were significantly older, had significantly higher NTproBNP, higher prevalence of atrial enlargement and thyroid disease. After multivariate analysis, advanced IAB was found to be independently associated with POAF.

CONCLUSIONS

IAB is a frequent finding among patients undergoing cardiac surgery. According to our results, advanced IAB is independently associated with POAF in younger patients (<65 years) undergoing cardiac surgery.

Postoperative atrial tachycardias after mitral valve surgery: Mechanisms and outcomes of catheter ablation

BACKGROUND

Atrial tachycardias (ATs) including atrial fibrillation are common arrhythmias occurring late after mitral valve (MV) surgery, and their management is challenging.

OBJECTIVE

The purpose of this study was to determine the electrophysiological mechanisms of ATs in patients with prior MV surgery and the long-term outcomes of catheter ablation.

METHODS

We studied 67 consecutive patients (mean age 59.4 ± 10.6 years; 41 men [61%]) with prior MV surgery who presented with ATs postoperatively between 2007 and 2015.

RESULTS

AT was clinically documented before the electrophysiology study in 55 patients, whereas in the remaining 12 patients AT was inducible at the study. A total of 99 ATs (35 spontaneous and 64 inducible) were characterized. Overall, the right atrium (RA) was the chamber of origin in 56%. The underlying mechanism was macroreentry in 91 cases and included typical RA flutter (n = 37), mitral annular flutter (n = 21), incisional right AT (n = 16), roof-dependent reentry (n = 12), and local left atrial reentry (n = 5). Eight focal ATs were also documented: 6 from the left atrium and 2 from the RA. Left-sided ATs were more common in patients with prior Maze procedure (53%), and mitral annular flutter was twice as prevalent in this group (42% vs 21%; P = .05). The ablation was acutely successful in 98.5%. Freedom from atrial arrhythmias was 62% at 12 months, with 42% requiring more than 1 procedure.

CONCLUSION

Macroreentry is the predominant AT mechanism in patients with prior MV surgery. Circuits are most often localized to the RA, with left-sided ATs more common in patients with prior Maze procedure. Repeat procedures are common and outcomes with 1 year complete AT control good.

Predictive Genomics of Adverse Events After Cardiac Surgery

Significant, yet highly individual, thrombotic and inflammatory responses to surgery provide an excellent opportunity for insight into the genomic impact upon a patient's postoperative course. Cardiac surgery elicits the most profound perioperative disturbance and is associated with the highest incidence of adverse outcomes of any elective surgical procedure. Thus, cardiac surgical patients are an ideal population in which to evaluate the influence of complex traits on perioperative morbidity and mortality. This review describes the application of fundamental genetics upon the occurrence of adverse outcomes after cardiac surgery and cardiac transplantation. Specific emphases include a brief primer of the principles of genetics concentrating on the effects of variation within the human genome upon clinical outcomes and the differences between so-called Mendelian traits and complex traits. Four important clinical diseases dealt with in this review as examples of the impact of genetic factors on clinical outcomes are the genetics of heparin-induced thrombocytopenia, heart transplantation rejection and vasculopathy, atrial fibrillation, and infection.

Atrial fibrillation and flutter following coronary artery bypass graft surgery: A retrospective study and review

Introduction and objectives

Atrial fibrillation is a common arrhythmia following coronary artery bypass graft surgery. Its incidence can range from 10 to 60% of patients undergoing coronary artery bypass graft. This rhythm can result in shorter or longer intervals between beats.

Methods

Medical records of 143 patients from the Queen’s Medical Center, Kuakini Medical Center, Saint Francis Medical Center, and Straub Hospital and Clinic, all of which are located in Honolulu, Hawaii were reviewed. An additional 39 records of patients who did not develop these complications were also reviewed as a control group. Patients were selected according to the ICD codes for atrial fibrillation/flutter and coronary artery bypass graft. Both anomalies can lead to increased health care costs, morbidity, and mortality. In this study, possible predisposing factors to these complications were investigated. The time of onset, weight gain, elapsed time, fluid status (in/out), hematocrit, and drug regimens were compared between the two groups.

Results

The differences in weight gain, fluid status, and hematocrit between the groups were not significant. There were a total of 17 different drugs prescribed to the group as a whole but not every patient received the same regimen.

Conclusions

Atrial fibrillation and flutter were found to be more common in males, particularly between the ages of 60 and 69 years. There were no other significant findings.

Left Atrial Appendage Velocity as a Predictor of Atrial Fibrillation After Cardiac Surgery

OBJECTIVE

To determine if there is an association between left atrial appendage velocity and the development of postoperative atrial fibrillation (POAF).

DESIGN

Single institution retrospective study performed between January 2013 and December 2013.

SETTING

Single-institution, university hospital.

PARTICIPANTS

Five hundred sixty-two adult patients undergoing cardiac surgery utilizing cardiopulmonary bypass.

INTERVENTIONS

No interventions for the purpose of this study.

MEASUREMENTS AND MAIN RESULTS

Left atrial appendage velocity, measured by transesophageal echocardiogram, ranged from 8 cm/sec to 126 cm/sec. The development of POAF within the first 3 days after cardiac surgery was 38.3%. The authors found that patients with a lower left atrial appendage velocity had a higher risk of developing POAF. In the adjusted logistic regression model, there was an 11% decrease in the odds of POAF for each 10-unit (cm/sec) increase in the left atrial appendage velocity (p = 0.044).

CONCLUSIONS

Decreasing left atrial appendage velocity is an independent predictor of risk for the development of POAF following cardiac surgery with cardiopulmonary bypass.

Echocardiographically derived effective valve opening area in mitral prostheses: a comparative analysis of various calculations using continuity equation and pressure half time method

Detection of dysfunctional mitral valve prostheses (MP) remains complex even though being optimized by considering echocardiographically derived prosthetic effective orifice area (VA). The purpose was to compare VA in MP, calculated by the continuity equation (CE) using peak velocities (CEVpeak), mean velocities (CEVmean), velocity-time integrals (CEVTI) and the pressure half time method using 220 ms as constant first (PHT220) as well as optimized constants. In 267 consecutive patients with normally functioning MP, we investigated VA within the first postoperative month. With increasing prosthetic sizes, mean VA values also increase in all calculations. The statistical curves demonstrate no significant difference in graphical steepness but show different levels. Comparison of mean VA showed the known systematic higher values of PHT220 and significantly decreased results when using CEVTI. This systematic difference between mean VA applying PHT220 versus CEVTI is approximately 1.0 cm(2) for all prosthetic sizes. Calculations via CEVpeak were close to the results of CEVTI. CEVmean produced values, which graphically correspond to the PHT220 curve. Only PHT220 detected the constructional equal prosthetic inner ring width between 29 and 31 mm. To compensate the systematic difference between CEVTI and PHT220, an optimized constant of 140 ms was calculated to be applied in PHT (PHT140). VA is a robust and, therefore, preferable parameter for investigating MP. If needed, both CE and PHT are applicable with a systematical difference between CEVTI and PHT220. An optimized constant of 140 ms (PHT140) should be applied when calculating VA of mitral valve prostheses via PHT.

Postoperative atrial fibrillation in non-cardiac and cardiac surgery: an overview

Postoperative atrial fibrillation (POAF) is the most common perioperative cardiac arrhythmia. A major risk factor for POAF is advanced age, both in non-cardiac and cardiac surgery. Following non-cardiac surgery, it is important to correct reversible conditions such as electrolytes imbalances to prevent the occurrence of POAF. Management of POAF consists of rate control and therapeutic anticoagulation if POAF persists for > 48 h and CHADS2 score > 2. After cardiac surgery, POAF affects a larger amount of patients. In addition to age, valve surgery carries the greatest risk for new AF. Rate control is the mainstay therapy in these patients. Prediction, prevention, and management of POAF should be further studied.

Does aortic valve disease etiology predict postoperative atrial fibrillation in patients undergoing aortic valve surgery?

ABSTRACT 

Background: Postoperative atrial fibrillation (POAF) is one of the most common complications of cardiac surgery and is associated with increased mortality and morbidity. Methods: We analyzed 830 patients without prior atrial fibrillation who underwent aortic valve replacement for aortic stenosis and/or aortic regurgitation. Results: The incidence of POAF was 38%. The patients with POAF were older, predominately male and hypertensive. The incidence of POAF was significantly different according to the valve etiology. At multivariate analysis, rheumatic and degenerative aortic valve etiologies were independent predictors of POAF. Conclusion: Aortic valve disease etiology affects the development of POAF. Rheumatic and degenerative etiologies have a higher risk of developing POAF independently of other clinical, functional and hemodynamic variables.

Atrial Fibrillation After Robotic Cardiac Surgery

Atrial fibrillation is one of the commonest complications after cardiac surgery and it is associated with considerable morbidity and increase in mortality. Recently, robotic approach to many heart operations has become feasible and reproducible. We here investigate and review the incidence of atrial fibrillation after robotic cardiac surgery. We found that its incidence is overall low and less than in conventional heart surgery.

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

BACKGROUND

Postoperative atrial fibrillation (POAF) is considered to be a transient arrhythmia in the first week after cardiac surgery.

OBJECTIVE

To determine the 30-day incidence and predictors of POAF and the value of postoperative overdrive biatrial pacing in the prevention of POAF.

METHODS

Patients (n = 148) without a history of atrial fibrillation undergoing aortic valve replacement or coronary artery bypass graft (CABG) were randomized into a pacing group (n = 75) and a control group. Patients were treated with standardized sotalol postoperatively. Rhythm was continuously monitored for 30 days by a transtelephonic event recorder.

RESULTS

POAF occurred in 73 (49.3%) patients, of whom 60 (40.5%) patients showed POAF during postoperative days (PODs) 0-5 and 37 (25%) patients during PODs 6-30. Prolonged aortic cross-clamp time was an important univariate predictor of 30-day and of late POAF (PODs 6-30; P = .017 and P = .03, respectively). Best-fit model analysis using 15 predetermined risk factors for POAF showed different positive interactive effects for early POAF (ie, baseline C-reactive protein levels with a history of myocardial infarction or low body mass index) and late POAF (ie, high body mass index, diabetes mellitus, baseline C-reactive protein, early POAF, creatinine levels, type of operation, smoking, and male gender). Biatrial pacing reduced the late POAF incidence in patients with aortic cross-clamp time >50 minutes (P = .006).

CONCLUSION

POAF is not limited to the first week after cardiac surgery but also occurs frequently in the postoperative month. It is desirable to regularly follow patients with POAF for atrial fibrillation recurrences after discharge.

Postoperative arrhythmias after cardiac surgery: incidence, risk factors, and therapeutic management

Arrhythmias are a known complication after cardiac surgery and represent a major cause of morbidity, increased length of hospital stay, and economic costs. However, little is known about incidence, risk factors, and treatment of early postoperative arrhythmias. Both tachyarrhythmias and bradyarrhythmias can present in the postoperative period. In this setting, atrial fibrillation is the most common heart rhythm disorder. Postoperative atrial fibrillation is often self-limiting, but it may require anticoagulation therapy and either a rate or rhythm control strategy. However, ventricular arrhythmias and conduction disturbances can also occur. Sustained ventricular arrhythmias in the recovery period after cardiac surgery may warrant acute treatment and long-term preventive strategy in the absence of reversible causes. Transient bradyarrhythmias may be managed with temporary pacing wires placed at surgery, but significant and persistent atrioventricular block or sinus node dysfunction can occur with the need for permanent pacing. We provide a complete and updated review about mechanisms, risk factors, and treatment strategies for the main postoperative arrhythmias.

Hemoglobin and B-type natriuretic peptide preoperative values but not inflammatory markers, are associated with postoperative morbidity in cardiac surgery: a prospective cohort analytic study

Introduction

Risk stratification in cardiac surgery significantly impacts outcome. This study seeks to define whether there is an independent association between the preoperative serum level of hemoglobin (Hb), leukocyte count (LEUCO), high sensitivity C-reactive protein (hsCRP), or B-type natriuretic peptide (BNP) and postoperative morbidity and mortality in cardiac surgery.

Methods

Prospective, analytic cohort study, with 554 adult patients undergoing cardiac surgery in a tertiary cardiovascular hospital and followed up for 12 months. The cohort was distributed according to preoperative values of Hb, LEUCO, hsCRP, and BNP in independent quintiles for each of these variables.

Results

After adjustment for all covariates, a significant association was found between elevated preoperative BNP and the occurrence of low postoperative cardiac output (OR 3.46, 95% CI 1.53–7.80, p = 0.003) or postoperative atrial fibrillation (OR 3.8, 95% CI 1.45–10.38). For the combined outcome (death/acute coronary syndrome/rehospitalization within 12 months), we observed an OR of 1.93 (95% CI 1.00–3.74). An interaction was found between BNP level and the presence or absence of diabetes mellitus. The OR for non-diabetics was 1.26 (95% CI 0.61–2.60) and for diabetics was 18.82 (95% CI 16.2–20.5). Preoperative Hb was also significantly and independently associated with the occurrence of postoperative low cardiac output (OR 0.33, 95% CI 0.13–0.81, p = 0.016). Both Hb and BNP were significantly associated with the lengths of intensive care unit and hospital stays and the number of transfused red blood cells (p < 0.002). Inflammatory markers, although associated with adverse outcomes, lost statistical significance when adjusted for covariates.

Conclusions

High preoperative BNP or low Hb shows an association of independent risk with postoperative outcomes, and their measurement could help to stratify surgical risk. The ability to predict the onset of atrial fibrillation or postoperative low cardiac output has important clinical implications. Our results open the possibility of designing studies that incorporate BNP measurement as a routine part of preoperative evaluation, and this strategy could improve upon the standard evaluation in terms of reducing adverse postoperative events.

Post-operative Atrial Fibrillation - Pathophysiology, Treatment and Prevention

Atrial fibrillation occurring after cardiac surgery has been the subject of intensive research over the past decades. However, the incidence remains high, despite numerous preventive and treatment strategies. In addition, several reports show that the impact of post-operative atrial fibrillation (POAF) is high. It is an independent risk factor for mortality after several years. These findings make clear that the pathophysiology of POAF is not fully understood and POAF-associated risks to some extent might be underestimated. On the one hand, excessive triggers during the acute post operative phase after cardiac surgery might initiate AF even in atria with low vulnerability. On the other hand, many patients undergoing surgery have an atrial substrate at the time of operation promoting AF not only in the post-operative phase but also in the days and weeks thereafter. Progress in our understanding of the AF mechanisms in general has provided valuable insights into processes involved in atrial structural remodeling due to advanced age, hypertension, obesity, and congestive heart failure. These patient characteristics strongly contribute to cardiac disease, predict POAF and likely have an impact on the risk of thrombus formation in the weeks and months after cardiac surgery. For a better understanding of the mechanisms involved, it is important to not only recognize the occurrence of POAF by continuous monitoring after surgery, but also to identity the extent of atrial vulnerability to AF in these patients.

Risk Factors for Post-Coronary Artery Bypass Grafting (CABG) Atrial Fibrillation and the Role of Aspirin and Beta Blockers in its Prevention

Background: Atrial fibrillation/flutter (AF) is the most common arrhythmia following coronary artery bypass grafting (CABG) and it increases morbidity and mortality associated with this procedure. The purpose of this study was to evaluate the predictability of this arrhythmia using previously identified risk factors and to assess the efficacy of recommended prophylactic beta blocker (BB) therapy in the prevention of post CABG AF. Methods: We performed a retrospective chart analysis of consecutive patients undergoing elective CABG during 1 year period. Patients who developed new onset AF after the surgery were designated as cases and those who did not, as controls. 41 different variables were analyzed using Chi-square test and independent sample t-test. Multivariate analysis was carried out using logistic regression model. Results: 23% patients undergoing CABG developed AF during post-operative period. Statistically significant differences were observed between the two groups in terms of age, use of peri-operative Aspirin (ASA), current smoking, previous history of AF, left atrial size, history of congestive heart failure (CHF) and brain natriuretic peptide (BNP) levels. In terms of prophylactic therapy, preoperative BB did not independently protect against post CABG AF. On multivariate analysis, only age, use of ASA and previous history of AF remained as independent predictors of post CABG AF. Conclusion: In our study population, the use of preoperative BB did not independently decrease the risk of post-CABGAF. Age, peri-operative ASA use and previous history of AF remained strong independent predictors of post- operative AF.

Perioperative heart-type fatty acid binding protein levels in atrial fibrillation after cardiac surgery

BACKGROUND

Postoperative atrial fibrillation (POAF) is common and associated with poor outcomes. Perioperative ischemia can alter arrhythmic substrate.

OBJECTIVE

To demonstrate an association between perioperative measurements of heart-type fatty acid binding protein (HT-FABP), a sensitive marker of ischemic myocardial injury.

METHODS

Blood samples from 63 inpatients undergoing coronary artery bypass surgery, valve surgery, or both were obtained before and up to 4 days after surgery. Continuous telemetry monitoring was used to detect POAF. Fifty-nine patients had at least 3 HT-FABP measurements. The relationship of enzyme-linked immunosorbent assay-measured HT-FABP with POAF was assessed by using joint logistic regression adjusted for age and surgery type.

RESULTS

Thirty-five patients (55%) developed POAF; these were, on average, older (69.3±10 years vs 60±11 years; P = .0019), with a higher prevalence of heart failure (43% vs 17%; P = .034), chronic obstructive lung disease (26% vs 4%; P = .017), preoperative calcium channel blocker use (29% vs 7%; P = .031), and more likely to undergo combined surgery (21% vs 11%, P = .049). The joint age- and coronary artery bypass surgery-adjusted model revealed that postoperative but not preoperative HT-FABP levels predicted POAF (coefficient 1.9±0.87; P = .03). Longer bypass time, prior infarction, and worse renal function were all associated with higher postoperative HT-FABP.

CONCLUSIONS

A greater rise of HT-FABP is associated with atrial fibrillation after cardiac surgery, suggesting that ischemic myocardial damage is a contributing underlying mechanism. Interventions that decrease perioperative ischemic injury may also decrease the occurrence of POAF.

Elevated pulmonary artery systolic pressures are associated with a lower risk of atrial fibrillation following lung transplantation

BACKGROUND

Atrial fibrillation (AF) is common after open-chest procedures, but the etiology remains poorly understood. Lung transplant procedures allow for the study of novel contributing factors.

METHODS

Records of lung transplant procedures performed at a single center between 2002 and 2009 were reviewed.

RESULTS

Of 174 patients, 27 (16%) had AF a median 6 days post-surgery. Post-operative AF patients less often had right ventricular hypertrophy (RVH) by either electrocardiogram (0 versus 14%, P=.042) or echocardiography (19% versus 47%, P=.006), and had lower pulmonary artery systolic pressures (PASP) (39 ± 12 versus 51 ± 22, P=.005). After multivariable adjustment, every 10-mm Hg increase in PASP was associated with a 31% reduction in the odds of post-operative AF (OR 0.69, 95% CI 0.49-0.98, P=.035). A higher pulmonary pressure was the only predictor independently associated with less post-operative AF.

CONCLUSIONS

Higher PASP was associated with a lower risk of AF after lung transplantation.

Postoperative atrial fibrillation is not associated with an increase risk of stroke or the type and number of grafts: a single-center retrospective analysis

BACKGROUND

Atrial fibrillation (AF) and atrial flutter are the 2 most common types of dysrhythmia in patients undergoing coronary artery bypass graft (CABG) surgery and are associated with increased morbidity and mortality. We sought to explore the association between the type and quantity of bypass grafts and cardiovascular outcomes in patients with postoperative AF (POAF).

HYPOTHESIS

The type and quantity of bypass grafts is associated with POAF.

METHODS

We queried the Society of Thoracic Surgery National Database for CABG operations, both with and without valve procedures, performed at Baystate Medical Center between January 2002 and July 2007. We used multivariable logistic regression modeling to identify predictors of POAF and to explore the impact of AF on major adverse cardiac outcomes in this post-CABG population.

RESULTS

A total of 3068 patients received CABG surgery, 187 (6.1%) of whom received concurrent valve replacement or repair. The incidence of POAF was 38.3%. POAF was significantly associated with readmission within 30 days (P < 0.009), increased length of stay (P << 0.0001), and a strong trend toward increased 30 day mortality (P = 0.058). There was no association between POAF and postoperative stroke (P = 0.92), graft type (P = nonsignificant) or number of grafts (P = nonsignificant).

CONCLUSIONS

Patients with POAF experienced increased morbidity and mortality as demonstrated by previous studies. Neither the number of grafts nor type of grafts was associated with POAF. Furthermore, the rate of stroke was not associated with POAF.

Incidence, risk factors, and outcomes for atrial arrhythmias in trauma patients

The purpose of this study is to determine the incidence, risk factors, and outcomes after the development of an atrial arrhythmia (AA) in trauma patients admitted to the intensive care unit (ICU). We performed a retrospective study of more than 7 years of trauma patients admitted to the ICU at an urban, academic Level I trauma center. Patients with AA, defined as atrial fibrillation, atrial flutter, or paroxysmal supraventricular tachycardia, were compared with patients without AA. Groups were compared by univariate and multivariate analysis. Three thousand, four hundred and ninety-nine trauma patients were admitted to the ICU during the study period and 210 (6%) developed an AA. AA patients were more likely to sustain blunt trauma, were older, more often female, more severely injured, and sustained more head injuries. The only independent risk factor for developing an AA was age > 55 years (odds ratio = 4.6, P < 0.01). Mortality was higher in the AA group (33% vs. 14%, P < 0.01) and AA was an independent risk factor for mortality (odds ratio = 1.7, P = 0.01). Twenty-eight per cent (n = 59) of AA patients received beta-blockers in the postinjury period, and these patients had lower mortality (22% vs. 37%, P = 0.04). AA occurs in 6 per cent of trauma patients admitted to the ICU. Developing an AA is an independent risk factor for mortality after trauma. Beta-blocker therapy was associated with decreased mortality in trauma patients with AA.

Post-operative atrial fibrillation: a maze of mechanisms

Post-operative atrial fibrillation (POAF) is one of the most frequent complications of cardiac surgery and an important predictor of patient morbidity as well as of prolonged hospitalization. It significantly increases costs for hospitalization. Insights into the pathophysiological factors causing POAF have been provided by both experimental and clinical investigations and show that POAF is ‘multi-factorial’. Facilitating factors in the mechanism of the arrhythmia can be classified as acute factors caused by the surgical intervention and chronic factors related to structural heart disease and ageing of the heart. Furthermore, some proarrhythmic mechanisms specifically occur in the setting of POAF. For example, inflammation and beta-adrenergic activation have been shown to play a prominent role in POAF, while these mechanisms are less important in non-surgical AF. More recently, it has been shown that atrial fibrosis and the presence of an electrophysiological substrate capable of maintaining AF also promote the arrhythmia, indicating that POAF has some proarrhythmic mechanisms in common with other forms of AF. The clinical setting of POAF offers numerous opportunities to study its mechanisms. During cardiac surgery, biopsies can be taken and detailed electrophysiological measurements can be performed. Furthermore, the specific time course of POAF, with the delayed onset and the transient character of the arrhythmia, also provides important insight into its mechanisms.

This review discusses the mechanistic interaction between predisposing factors and the electrophysiological mechanisms resulting in POAF and their therapeutic implications.

Determinants of postoperative atrial fibrillation and associated resource utilization in cardiac surgery

INTRODUCTION AND OBJECTIVES

Atrial arrhythmias occur after cardiac surgery in 10-65% of patients. The most common postoperative arrhythmia is atrial fibrillation (AF).

METHODS

The Tehran Heart Center Cardiovascular Research database (of 15 580 patients) was used to identify all patients who developed any form of AF as a postoperative complication following their first cardiac surgery (e.g. for coronary artery bypass grafting [CABG], valve surgery or both), with and without cardiopulmonary bypass, between June 2002 and March 2008.

RESULTS

Of the 15 580 patients who underwent a first cardiac surgery, 11 435 (73.4%) were male and their mean age was 58.16+/-10.11 years. New-onset AF developed postoperatively in 1129 (7.2%). New-onset AF occurred most frequently in patients who were aged > or =60 years and who had no history of beta-blocker use. In addition, patients were more likely to develop new-onset AF if they had valve surgery alone (16.5%) or CABG plus valve surgery combined (9.6%), needed intra-aortic balloon counterpulsation (IABC), or had a long cardiopulmonary bypass time. Multivariate analysis identified the following predictors of postoperative AF: older age, history of renal failure, congestive heart disease, operation type, longer perfusion time, and use of IABC. The incidence of early readmission (4.4%) was significantly higher in patients with postoperative AF, as was the duration of hospitalization, both overall and postoperatively. The short-term postoperative mortality rate was 3.8%.

CONCLUSIONS

Atrial fibrillation frequently develops after cardiac surgery and is associated not only with increased morbidity and mortality, but also with increased use of health-care resources.

Effect of race on the frequency of postoperative atrial fibrillation following coronary artery bypass grafting

Atrial fibrillation (AF) commonly complicates the postoperative course after coronary artery bypass grafting (CABG). Among the general population, African Americans have been shown to have a lower prevalence of AF than European Americans. Although many factors have been identified to predict risk for postoperative AF, race has not been examined. All patients aged ≥18 years who underwent CABG at Henry Ford Hospital during a 5-year period from January 1, 2004, to December 31, 2008, were included. Patients were excluded for any previous diagnosis of AF or if they had concomitant valve surgery at the time of CABG. The incidence of AF was determined by International Classification of Diseases, Ninth Revision, coding from postoperative hospitalization records. Overall, 1,001 patients were eligible for analysis. Of these, 731 (73%) were European American and 270 (27%) were African American. The African American group had a higher prevalence of hypertension (75.6% vs 58.8%, p <0.001) and heart failure (22.6% vs 15.7%, p = 0.01) and a trend toward a higher prevalence of diabetes mellitus (38.1% vs 33.4%, p = 0.159). Postoperative AF was diagnosed in 214 European Americans (29.3%) and 50 African Americans (18.5%) (p = 0.001). In multivariate analysis adjusting for age strata, gender, hypertension, diabetes, and heart failure, African Americans had less postoperative AF than European Americans, with an adjusted odds ratio of 0.539 (95% confidence interval 0.374 to 0.777, p = 0.001). In conclusion, African Americans have a significantly reduced incidence of AF compared to European Americans after CABG.

Quantitative electrocardiography for predicting postoperative atrial fibrillation after cardiac surgery

BACKGROUND

Atrial fibrillation (AF) after cardiac surgery is a common marker of poor outcomes. Quantitative electrocardiographic (ECG) measurements may be valuable predictors of postoperative AF.

METHODS

We evaluated clinical and ECG predictors of postoperative AF in 13,356 patients who underwent cardiac surgery in sinus rhythm.

RESULTS

A total of 4724 patients (35%) developed postoperative AF. P-wave amplitude in leads aVR and V(1) were the strongest ECG predictors. A less negative P-wave amplitude in lead aVR was associated with increased risk for postoperative AF (odds ratio, 1.46; 95% confidence interval, 1.32-1.61), as was a more positive or a more negative P-wave amplitude in lead V(1) (odds ratio, 1.25; 95% confidence interval, 1.16-1.36) after adjusting for clinical and procedural predictors of postoperative AF. Reclassification analysis showed a 7% discrimination improvement (P < .0001).

CONCLUSIONS

P-wave amplitude in lead aVR and lead V(1) are powerful predictors of postoperative AF and, in combination with other clinical predictors, can guide application of prophylactic interventions.

Incidence, risk factors, and clinical outcomes of atrial fibrillation and atrial flutter after heart transplantation

Atrial fibrillation (AF) and atrial flutter (AFL) after heart transplantation (HT) has been associated with increased mortality. Diverse incidence rates have been reported to date, with no clear classification according to the time of onset of such arrhythmias. We determined the incidence of AF/AFL using the time of onset after HT and analyzed the associated risk factors and outcomes. We performed a retrospective study of 228 HT recipients (March 1996 to July 2007), including donor and recipient demographics, gender mismatch, ischemia time, surgical anastomosis, time of onset of AF/AFL, acute cellular rejection, left ventricular systolic function, and all-cause mortality. The mean age of the donors (81% men) was 30 +/- 12 years and of the recipients (78% men) was 53 +/- 11 years. AF/AFL occurred in 45 patients (20%): 24 (11%) in the first 30 days, 10 (4%) within the 31 days to 1 year, and 11 (5%) after 1 year. When the patients with AF/AFL were compared to those with sinus rhythm, the significant difference was the older mean age of the donors (p = 0.001) and the recipients (p = 0.02). The all-cause mortality rate was 43% for those with AF/AFL compared to 23% for those with sinus rhythm (hazard ratio 2.45; 95% confidence interval 1.2 to 4.8), mostly driven by the greater mortality in the later-onset AF/AFL group (>30 days after HT). In conclusion, AF and AFL have an incidence of 20% after HT and are associated with increased overall mortality compared to that in patients in sinus rhythm. AF/AFL is more common within the first 30 days of HT, with an overall incidence of 20%. Older donor and recipient age is a risk factor associated with AF/AFL.

Automatic detection and classification of human epicardial atrial unipolar electrograms

This paper describes an unsupervised signal processing method applied to three-channel unipolar electrograms recorded from human atria. These were obtained by epicardial wires sutured on the right and left atria after coronary artery bypass surgery. Atrial (A) and ventricular (V) activations had to be detected and identified on each channel, and gathered across the channels when belonging to the same global event. The algorithm was developed and optimized on a training set of 19 recordings of 5 min. It was assessed on twenty-seven 2 h recordings taken just before the onset of a prolonged atrial fibrillation for a total of 1593697 activations that were validated and classified as normal atrial or ventricular activations (A, V) and premature atrial or ventricular activations (PAA, PVA). 99.93% of the activations were detected, and amongst these, 99.89% of the A and 99.75% of the V activations were correctly labelled. In the subset of the 39705 PAA, 99.83% were detected and 99.3% were correctly classified as A. The false positive rate was 0.37%. In conclusion, a reliable fully automatic detection and classification algorithm was developed that can detect and discriminate A and V activations from atrial recordings. It can provide the time series needed to develop a monitoring system aiming to identify dynamic predictors of forthcoming cardiac events such as postoperative atrial fibrillation.

Postoperative atrial fibrillation

Atrial fibrillation is a common arrhythmia that occurs after cardiac surgery. It is associated with an increase in morbidity, length of hospital stay and mortality. Patients who are at higher risk of postoperative atrial fibrillation should receive prophylactic treatment. Atrial fibrillation usually resolves spontaneously after heart rate is controlled; however, if patients are highly symptomatic or hemodynamically unstable, sinus rhythm should be restored by electrical or pharmacologic cardioversion.

Atrial fibrillation following cardiac surgery: clinical features and preventative strategies

Atrial fibrillation (AF) is a common complication of cardiac surgery, with an increasing incidence. Post-operative AF results in many complications and increased healthcare resources. Despite substantial interest in the prediction and prevention of post-operative AF, as well as guidelines for the management of this common arrhythmia, there is still some uncertainty about appropriate risk stratification and management. The aim of this review article is to provide an overview of clinical predictive features for the development of AF following cardiac surgery and suitable preventive measures, using both antiarrhythmic and non-antiarrhythmic strategies.