The risk for acute coronary syndrome associated with atrial fibrillation among ED patients with chest pain syndromes

Coronary artery disease among patients admitted with atrial fibrillation and chest pain

INTRODUCTION

Patients who present to the emergency department with chest pain during an episode of atrial fibrillation (AF) impose a clinical challenge regarding the source of pain - being coronary artery disease (CAD) or AF in origin. The aim of this study was to identify clinical, imaging or laboratory markers which can predict significant CAD among patients with an AF episode and chest pain.

METHODS

We included 57 consecutive patients admitted to our hospital with AF and chest pain. All patients underwent coronary evaluation. Significant CAD was defined as >50% stenosis in a major coronary artery by coronary angiography or cardiac CT. We compared CAD and non-CAD groups and analyzed risk factorsby regression analysis.

RESULTS

Twenty-four patients (42%) were diagnosed with- and 33 patients (58%) without obstructive CAD. In a multivariate analysis of regional wall motion abnormality (RWMA), elevated troponin and hypertension were found to be predictors for CAD [odds ratio (OR), 22.4 (confidence interval (CI), 1.8-272.4; P  = 0.02); OR, 5.6 (CI, 1-31.0; P  = 0.05) and OR, 21.4 (CI, 1.6-284.6; P  = 0.02), respectively]. There were no significant differences regarding the rate of typical chest pain at presentation in the CAD vs. the non-CAD group [13 (54%) vs. 20 (60%), P  = 0.374], or in ECG ST-changes [12 (50%) vs.9 (27%), respectively; P  = 0.08].

CONCLUSION

In patients who present acutely with chest pain and AF, troponin elevation and RWMA appear to be highly predictive of obstructive CAD, whereas clinical symptoms and ECG changes are not predictive. These findings may be helpful for guiding the management of patients admitted with AF and chest pain.

High incidence of newly diagnosed obstructive coronary artery disease regardless of chest pain detected on pre-procedural cardiac computed tomography angiography in patients undergoing atrial fibrillation ablation

BACKGROUND

Cardiac computed tomography (CT) is often performed before catheter ablation of atrial fibrillation to map atrial and pulmonary anatomy. Incident coronary artery disease (CAD) may also be diagnosed during cardiac CT angiography (CTA). Our aim was to assess whether coronary CTA might be able to identify a significant proportion of patients with obstructive CAD prior to their catheter ablation procedure event, even in asymptomatic patients.

METHODS

Consecutive patients undergoing pre-ablation coronary CTA for atrial fibrillation between 2013 and 2020 were retrospectively selected. Patients with previously diagnosed CAD were excluded. Obstructive CAD was defined as ≥50% luminal stenosis. We analyzed the relationship between obstructive CAD, any chest pain, and traditional risk factors.

RESULTS

Overall, 2321 patients [median age 63.0 (54.4-69.2), 1052/2321 (45.3%) female] underwent coronary CTA and 488/2321 (21.0%) were diagnosed with obstructive CAD. There was no difference regarding the rate of obstructive CAD in patients with any chest pain compared to patients without any chest pain [91/404 (22.5%) vs. 397/1917 (20.7%), P = 0.416, respectively). The following parameters were associated with obstructive CAD: age > 65 years [odds ratio (OR) = 2.51; 95% confidence interval (CI), 2.02-3.13; P < 0.001), male sex (OR = 1.59; 95% CI, 1.28-1.98; P < 0.001), hypertension (OR = 1.40; 95% CI, 1.08-1.81; P = 0.012), diabetes (OR = 1.50; 95% CI, 1.13-1.99; P = 0.006), dyslipidaemia (OR = 1.33; 95% CI, 1.07-1.66; P = 0.011) and history of smoking (OR = 1.34; 95% CI, 1.07-1.68; P = 0.011).

CONCLUSIONS

The high prevalence of obstructive CAD even in patients without chest pain highlights the importance of additional coronary artery diagnostics in patients undergoing left atrial CTA awaiting catheter ablation for atrial fibrillation. These patients regardless of chest pain thus may require further risk modification to decrease their potential ischemic and thromboembolic risk.

Symptom Clusters in Adults With Chronic Atrial Fibrillation

BACKGROUND

Symptom clusters have not previously been explored among individuals with atrial fibrillation of any type.

OBJECTIVE

The purpose of this study is to determine the number of symptom clusters present among adults with chronic atrial fibrillation and to explore sociodemographic and clinical factors potentially associated with cluster membership.

METHODS

This was a cross-sectional secondary data analysis of 335 Australian community-dwelling adults with chronic (recurrent paroxysmal, persistent, or permanent) atrial fibrillation. We used self-reported symptoms and agglomerative hierarchical cluster analysis to determine the number and content of symptom clusters present.

RESULTS

There were slightly more male (52%) than female participants, with a mean (SD) age of 72 (11.25) years. Three symptom clusters were evident, including a vagal cluster (nausea and diaphoresis), a tired cluster (fatigue/lethargy, weakness, syncope/dizziness, and dyspnea/breathlessness), and a heart cluster (chest pain/discomfort and palpitations/fluttering). We compared patient characteristics among those with all the symptoms in the cluster, those with some of the symptoms in the cluster, and those with none of the symptoms in the cluster. The only statistically significant differences were in age, gender, and the use of antiarrhythmic medications for the heart cluster. Women were more likely to have the heart symptom cluster than men were. Individuals with all of the symptoms in the heart cluster were younger (69.6 vs 73.7 years; P = .029) than those with none of the symptoms in the heart cluster and were more likely to be on antiarrhythmic medications.

CONCLUSION

Three unique atrial fibrillation symptom clusters were identified in this study population.

Cardiac computed tomography in patients with symptomatic new-onset atrial fibrillation, rule-out acute coronary syndrome, but with intermediate pretest probability for coronary artery disease admitted to a chest pain unit

Background

Atrial fibrillation (AF) and coronary artery disease (CAD) may be encountered coincidently in a large portion of patients. However, data on coronary artery calcium burden in such patients are lacking. Thus, we sought to determine the value of cardiac computed tomography (CCT) in patients presenting with new-onset AF associated with an intermediate pretest probability for CAD admitted to a chest pain unit (CPU).

Methods

Calcium scores (CS) of 73 new-onset, symptomatic AF subjects without typical clinical, electrocardiographic, or laboratory signs of acute coronary syndrome (ACS) admitted to our CPU were analyzed. In addition, results from computed tomography angiography (CTA) were related to coronary angiography findings whenever available.

Results

Calcium scores of zero were found in 25%. Median Agatston score was 77 (interquartile range: 1–270) with gender- and territory-specific dispersal. CS scores above average were present in about 50%, high (> 400)-to-very high (> 1000) CS scores were found in 22%. Overall percentile ranking showed a relative accordance to the reference percentile distribution. Additional CTA was performed in 47%, revealing stenoses in 12%. Coronary angiography was performed in 22% and resulted in coronary intervention or surgical revascularization in 7%. On univariate analysis, CS > 50th percentile failed to serve as an independent determinant of significant stenosis during catheterization.

Conclusions

Within a CPU setting, relevant CAD was excluded or confirmed in almost 50%, the latter with a high proportion of coronary angiographies and subsequent coronary interventions, underlining the diagnostic value of CCT in symptomatic, non-ACS, new-onset AF patients when admitted to a CPU.

Coronary Artery Calcium as an Independent Surrogate Marker in the Risk Assessment of Patients With Atrial Fibrillation and an Intermediate Pretest Likelihood for Coronary Artery Disease Admitted to a German Chest Pain Unit

BACKGROUND

About 10% of patients admitted to a chest pain unit (CPU) exhibit atrial fibrillation (AF).

HYPOTHESIS

To determine whether calcium scores (CS) are superior over common risk scores for coronary artery disease (CAD) in patients presenting with atypical chest pain, newly diagnosed AF, and intermediate pretest probability for CAD within the CPU.

METHODS

In 73 subjects, CS was related to the following risk scores: Global Registry of Acute Coronary Events (GRACE) score, including a new model of a frequency-normalized approach; Thrombolysis In Myocardial Infarction score; European Society of Cardiology Systematic Coronary Risk Evaluation (SCORE); Framingham risk score; and Prospective Cardiovascular Münster Study score. Revascularization rates during index stay were assessed.

RESULTS

Median CS was 77 (interquartile range, 1-270), with higher values in men and the left anterior descending artery. Only the modified GRACE (ρ = 0.27; P = 0.02) and the SCORE (ρ = 0.39; P < 0.005) were significantly correlated with CS, whereas the GRACE (τ = 0.21; P = 0.04) and modified GRACE (τ = 0.23; P = 0.02) scores were significantly correlated with percentile groups. Only the CS significantly discriminated between those with and without stenosis (P < 0.01).

CONCLUSIONS

Apart from modified GRACE score, overall correlations between risk scores and calcium burden, as well as revascularization rates during index stay, were low. By contrast, the determination of CS may be used as an additional surrogate marker in risk stratification in AF patients with intermediate pretest likelihood for CAD admitted to a CPU.

Predictors of Elevated Cardiac Enzyme Levels in Hospitalized Patients with Atrial Fibrillation and No Known Coronary Artery Disease

We retrospectively studied the predictive capabilities of elevated cardiac enzyme levels in terms of the prognosis of patients who were hospitalized with atrial fibrillation and who had no known coronary artery disease. Among 321 patients with atrial fibrillation, 60 without known coronary artery disease had their cardiac enzyme concentrations measured during hospitalization and underwent stress testing or cardiac catheterization within 12 months before or after hospitalization. We then compared the clinical and electrocardiographic characteristics of the 20 patients who had elevated cardiac enzyme levels and the 40 patients who had normal levels. Age, sex, and comorbidities did not differ between the groups. In the patients with elevated cardiac enzyme levels, the mean concentrations of troponin T and creatine kinase-MB isoenzymes were 0.08 ± 0.08 ng/mL and 6.49 ± 4.94 ng/mL, respectively. In univariate analyses, only peak heart rate during atrial tachyarrhythmia was predictive of elevated enzyme levels (P <0.0001). Mean heart rate was higher in the elevated-level patients (146 ± 22 vs 117 ± 29 beats/min; P=0.0007). Upon multivariate analysis, heart rate was the only independent predictor of elevated levels. Coronary artery disease was found in only 2 patients who had elevated levels and in one patient who had normal levels (P=0.26). Increased myocardial demand is probably why the presenting heart rate was predictive of elevated cardiac enzyme levels. Most patients with elevated enzyme levels did not have coronary artery disease, and none died of cardiac causes during the 6-month follow-up period. To validate our findings, larger studies are warranted.

Diagnostic Evaluation and Follow-Up of Patients with Atrial Fibrillation

In this article, a review of the diagnostic evaluation and outpatient follow-up of patients with atrial fibrillation is presented. After exploring details of symptoms, past medical history, quality of life, and physical exam findings, diagnostic tools are then discussed. Furthermore, important considerations after the initial diagnosis and treatment of patients with atrial fibrillation are discussed.

How does Chronic Atrial Fibrillation Influence Mortality in the Modern Treatment Era?

Atrial fibrillation (AF) continues to impose a significant burden upon healthcare resources. A sustained increase in the ageing population and better survival from conditions such as ischaemic heart disease have ensured that both the incidence and prevalence of AF continue to increase significantly. AF can lead to complications such as embolism and heart failure and these acting in concert with its associated co-morbidities portend increased mortality risk. Whilst some studies suggest that the mortality risk from AF is due to the "bad company it keeps" i.e. the associated co-morbidities rather than AF itself; undoubtedly some of the mortality is also due to the side-effects of various therapeutic strategies (anti-arrhythmic drugs, bleeding side-effects due to anti-coagulants or invasive procedures). Despite several treatment advances including newer anti-arrhythmic drugs and developments in catheter ablation, anti-coagulation remains the only effective means to reduce the mortality due to AF. Warfarin has been used as the oral anticoagulant in the treatment of AF for many years but suffers from disadvantages such as unpredictable INR levels, bleeding risks and need for haematological monitoring. This has therefore spurred a renewed interest in research and clinical studies directed towards developing safer and more efficacious anti-coagulants. We shall review in this article the epidemiological features of AF-related mortality from several studies as well as the cardiovascular and non-cardiac mortality mechanisms. We shall also elucidate why a rhythm control strategy has appeared to be counter-productive and attempt to predict the likely future impact of novel anti-coagulants upon mortality reduction in AF.

Diagnostic evaluation and follow-up of patients with atrial fibrillation

In this article, a review of the diagnostic evaluation and outpatient follow-up of patients with atrial fibrillation is presented. After exploring details of symptoms, past medical history, quality of life, and physical exam findings, diagnostic tools are then discussed. Furthermore, important considerations after the initial diagnosis and treatment of patients with atrial fibrillation are discussed.

Usefulness of a low CHADS2 or CHA2DS2-VASc score to predict normal diagnostic testing in emergency department patients with an acute exacerbation of previously diagnosed atrial fibrillation

International guidelines do not specify what testing should be performed during emergency department (ED) evaluations for patients presenting with an exacerbation of previously diagnosed atrial fibrillation (AF). We hypothesized that low CHADS2 and CHA2DS2-VASc scores predict normal routine diagnostic testing in these patients. We conducted an analysis within a prospective observational cohort study at a university-affiliated hospital. We included patients with previously diagnosed AF and who presented to the ED primarily for an AF-related complaint. Logistic regression was used to analyze the association between CHADS2 and CHA2DS2-VASc scores and abnormal results for blood counts, electrolytes, cardiac markers, thyroid function, and chest x-rays. We included 216 patients in this analysis. The odds ratios (95% confidence interval) for each point increase in CHADS2 for abnormal blood counts, electrolytes, troponin I, brain natriuretic peptide, thyroid function, and chest x-ray were 1.28 (0.99 to 1.65), 1.48 (1.19 to 1.84), 1.42 (1.10 to 1.82), 1.66 (1.15 to 2.41), 0.95 (0.70 to 1.29), and 1.17 (0.94 to 1.44), respectively. The corresponding odds ratios (95% confidence interval) for each point increase in CHA2DS2-VASc were 1.17 (0.96 to 1.42), 1.27 (1.09 to 1.49), 1.30 (1.07 to 1.57), 1.57 (1.18 to 2.10), 0.98 (0.79 to 1.22), and 1.14 (0.97 to 1.33), respectively. Among ED patients with established AF who underwent evaluation for acutely symptomatic AF, nearly 3/4 of routine diagnostic tests return to normal. In conclusion, patients with CHADS2 or CHA2DS2-VASc score of 0 have the lowest likelihood of abnormal studies and may represent an easily identifiable group of patients who need fewer ED tests.

Oxidative Stress and Microcirculatory Flow Abnormalities in the Ventricles during Atrial Fibrillation

Patients with atrial fibrillation (AF) often present with typical angina pectoris and mildly elevated levels of cardiac troponin (non-ST-segment elevation myocardial infarction) during an acute episode of AF. However, in a large proportion of these patients, significant coronary artery disease is excluded by coronary angiography, which suggests that AF itself influences myocardial blood flow. The present review summarizes the effect of AF on the occurrence of ventricular oxidative stress, redox-sensitive signaling pathways and gene expression, and microcirculatory flow abnormalities in the left ventricle.

Can we predict outcomes in atrial fibrillation?

Atrial fibrillation (AF) is the most common arrhythmia encountered by generalists and cardiologists alike. Much of the attendant morbidity from AF arises from systemic embolic complications which are effectively reduced with utilization of anti-platelet and/or anticoagulant therapy. The systemic embolic complications of AF and the medical therapy to attenuate these risks are very well established. Through the course of this review, we aim to highlight the complex relationship between AF and other, "non-embolic" outcomes. The presence of AF has been demonstrated to be associated with a 1.5 to 2-fold increase in mortality across numerous observational cohorts. Still further, AF frequently coexists with heart failure, whether as a causative factor or a consequence of underlying structural heart disease or neurohumoral derangement, where its presence is associated with worse clinical outcomes. Whether AF is an independent risk factor for acute coronary syndromes (ACS) remains controversial, though its occurrence in patients with ACS has been shown to be associated with adverse outcomes both in observational cohorts as well as clinical trial populations. Individuals with AF have a 1.5 to 3-fold increase in the rate of hospitalization and are at elevated risk for other arrhythmic disorders including both bradyarrhythmias as well as tachyarrhythmias. AF leads to considerable morbidity and mortality for patients and exacts a tremendous financial toll on the healthcare system-estimated to range from $6.0 to $26.0 billion. Given the current demographic transition in developed countries, the prevalence of AF will continue to increase and the need for refined approaches to risk stratification and pharmacotherapeutic interventions to attenuate the burden on patients will only become more important.

Sex differences in clinical presentation, management and outcome in emergency department patients with chest pain

OBJECTIVE

We sought to assess sex differences in clinical presentation, management and outcome in emergency department (ED) patients with chest pain, and to measure the association between female sex and coronary angiography within 30 days.

METHODS

We conducted a prospective cohort study in an urban academic ED between Jul. 1, 2007, and Apr. 1, 2008. We enrolled patients over 24 years of age with chest pain and possible acute coronary syndrome (ACS).

RESULTS

Among the 970 included patients, 386 (39.8%) were female. Compared with men, women had a lower prevalence of known coronary artery disease (21.0% v. 34.2%, p < 0.001) and a lower frequency of typical pain (37.1% v. 45.7%, p = 0.01). Clinicians classified a greater proportion of women as having a low (< 10%) pretest probability for ACS (85.0% v. 76.4%, p = 0.001). Despite similar rates of electrocardiography, troponin T and stress testing between sexes, there was a lower rate of acute myocardial infarction (AMI) (4.7% v. 8.4%, p = 0.03) and positive stress test results (4.4% v. 7.9%, p = 0.03) in women. Women were less frequently referred for coronary angiography (9.3% v. 18.9%, p < 0.001). The adjusted association between female sex and coronary angiography was not significant (odds ratio 0.63, 95% confidence interval 0.37-1.10).

CONCLUSION

Women had a lower rate of AMI and a lower rate of positive stress test results despite similar rates of testing between sexes. Although women were less frequently referred for coronary angiography, these data suggest that sex differences in management were likely appropriate for the probability of disease.

A clinical prediction model to estimate risk for 30-day adverse events in emergency department patients with symptomatic atrial fibrillation

STUDY OBJECTIVE

Atrial fibrillation affects more than 2 million people in the United States and accounts for nearly 1% of emergency department (ED) visits. Physicians have little information to guide risk stratification of patients with symptomatic atrial fibrillation and admit more than 65%. Our aim is to assess whether data available in the ED management of symptomatic atrial fibrillation can estimate a patient's risk of experiencing a 30-day adverse event.

METHODS

We systematically reviewed the electronic medical records of all ED patients presenting with symptomatic atrial fibrillation between August 2005 and July 2008. Predefined adverse outcomes included 30-day ED return visit, unscheduled hospitalization, cardiovascular complication, or death. We performed multivariable logistic regression to identify predictors of 30-day adverse events. The model was validated with 300 bootstrap replications.

RESULTS

During the 3-year study period, 914 patients accounted for 1,228 ED visits. Eighty patients were excluded for non-atrial-fibrillation-related complaints and 2 patients had no follow-up recorded. Of 832 eligible patients, 216 (25.9%) experienced at least 1 of the 30-day adverse events. Increasing age (odds ratio [OR] 1.20 per decade; 95% confidence interval [CI] 1.06 to 1.36 per decade), complaint of dyspnea (OR 1.57; 95% CI 1.12 to 2.20), smokers (OR 2.35; 95% CI 1.47 to 3.76), inadequate ventricular rate control (OR 1.58; 95% CI 1.13 to 2.21), and patients receiving β-blockers (OR 1.44; 95% CI 1.02 to 2.04) were independently associated with higher risk for adverse events. C-index was 0.67.

CONCLUSION

In ED patients with symptomatic atrial fibrillation, increased age, inadequate ED ventricular rate control, dyspnea, smoking, and β-blocker treatment were associated with an increased risk of a 30-day adverse event.

Acute atrial tachyarrhythmia induces angiotensin II type 1 receptor-mediated oxidative stress and microvascular flow abnormalities in the ventricles

Aims

Patients with paroxysmal atrial fibrillation (AF) often present with typical angina pectoris and mildly elevated levels of cardiac troponin (non ST-segment elevation myocardial infarction) during an arrhythmic event. However, in a large proportion of these patients, significant coronary artery disease is excluded by coronary angiography. Here we explored the potential underlying mechanism of these events.

Methods and results

A total of 14 pigs were studied using a closed chest, rapid atrial pacing (RAP) model. In five pigs RAP was performed for 7 h (600 b.p.m.; n = 5), in five animals RAP was performed in the presence of angiotensin-II type-1-receptor (AT₁-receptor) inhibitor irbesartan (RAP+Irb), and four pigs were instrumented without intervention (Sham). One-factor analysis of variance was performed to assess differences between and within the three groups. Simultaneous measurements of fractional flow reserve (FFR) and coronary flow reserve (CFR) before, during, and after RAP demonstrated unchanged FFR (P = 0.327), but decreased CFR during RAP (RAP: 67.7 ± 7.2%, sham: 97.2 ± 2.8%, RAP+Irb: 93.2 ± 3.3; P = 0.0013) indicating abnormal left ventricular (LV) microcirculation. Alterations in microcirculatory blood flow were accompanied by elevated ventricular expression of NADPH oxidase subunit Nox2 (P = 0.039), lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1, P = 0.004), and F₂-isoprostane levels (P = 0.008) suggesting RAP-related oxidative stress. Plasma concentrations of cardiac troponin-I (cTn-I) increased in RAP (RAP: 613.3 ± 125.8 pmol/L vs. sham: 82.5 ± 12.5 pmol/L; P = 0.013), whereas protein levels of eNOS and LV function remained unchanged. RAP+Irb prevented the increase of Nox2, LOX-1, and F₂-isoprostanes, and abolished the impairment of microvascular blood flow.

Conclusion

Rapid atrial pacing induces AT₁-receptor-mediated oxidative stress in LV myocardium that is accompanied by impaired microvascular blood flow and cTn-I release. These findings provide a plausible mechanism for the frequently observed cTn-I elevation accompanied with typical angina pectoris symptoms in patients with paroxysmal AF and normal (non-stenotic) coronary arteries.