Prognostic significance of troponin level in 3121 patients presenting with atrial fibrillation (The NIHR Health Informatics Collaborative TROP-AF study)

Phenogrouping heart failure with preserved or mildly reduced ejection fraction using electronic health record data

BACKGROUND

Heart failure (HF) with preserved or mildly reduced ejection fraction includes a heterogenous group of patients. Reclassification into distinct phenogroups to enable targeted interventions is a priority. This study aimed to identify distinct phenogroups, and compare phenogroup characteristics and outcomes, from electronic health record data.

METHODS

2,187 patients admitted to five UK hospitals with a diagnosis of HF and a left ventricular ejection fraction ≥ 40% were identified from the NIHR Health Informatics Collaborative database. Partition-based, model-based, and density-based machine learning clustering techniques were applied. Cox Proportional Hazards and Fine-Gray competing risks models were used to compare outcomes (all-cause mortality and hospitalisation for HF) across phenogroups.

RESULTS

Three phenogroups were identified: (1) Younger, predominantly female patients with high prevalence of cardiometabolic and coronary disease; (2) More frail patients, with higher rates of lung disease and atrial fibrillation; (3) Patients characterised by systemic inflammation and high rates of diabetes and renal dysfunction. Survival profiles were distinct, with an increasing risk of all-cause mortality from phenogroups 1 to 3 (p < 0.001). Phenogroup membership significantly improved survival prediction compared to conventional factors. Phenogroups were not predictive of hospitalisation for HF.

CONCLUSIONS

Applying unsupervised machine learning to routinely collected electronic health record data identified phenogroups with distinct clinical characteristics and unique survival profiles.

Fibrinaloid Microclots and Atrial Fibrillation

Atrial fibrillation (AF) is a comorbidity of a variety of other chronic, inflammatory diseases for which fibrinaloid microclots are a known accompaniment (and in some cases, a cause, with a mechanistic basis). Clots are, of course, a well-known consequence of atrial fibrillation. We here ask the question whether the fibrinaloid microclots seen in plasma or serum may in fact also be a cause of (or contributor to) the development of AF. We consider known 'risk factors' for AF, and in particular, exogenous stimuli such as infection and air pollution by particulates, both of which are known to cause AF. The external accompaniments of both bacterial (lipopolysaccharide and lipoteichoic acids) and viral (SARS-CoV-2 spike protein) infections are known to stimulate fibrinaloid microclots when added in vitro, and fibrinaloid microclots, as with other amyloid proteins, can be cytotoxic, both by inducing hypoxia/reperfusion and by other means. Strokes and thromboembolisms are also common consequences of AF. Consequently, taking a systems approach, we review the considerable evidence in detail, which leads us to suggest that it is likely that microclots may well have an aetiological role in the development of AF. This has significant mechanistic and therapeutic implications.

Emergency medicine updates: Atrial fibrillation with rapid ventricular response

INTRODUCTION

Atrial fibrillation (AF) may lead to stroke, heart failure, and death. When AF occurs in the context of a rapid ventricular rate/response (RVR), this can lead to complications, including hypoperfusion and cardiac ischemia. Emergency physicians play a key role in the diagnosis and management of this dysrhythmia.

OBJECTIVE

This paper evaluates key evidence-based updates concerning AF with RVR for the emergency clinician.

DISCUSSION

Differentiating primary and secondary AF with RVR and evaluating hemodynamic stability are vital components of ED assessment and management. Troponin can assist in determining the risk of adverse outcomes, but universal troponin testing is not required in patients at low risk of acute coronary syndrome or coronary artery disease - especially patients with recurrent episodes of paroxysmal AF that are similar to their prior events. Emergent cardioversion is indicated in hemodynamically unstable patients. Rate or rhythm control should be pursued in hemodynamically stable patients. Elective cardioversion is a safe option for select patients and may reduce AF symptoms and risk of AF recurrence. Rate control using beta blockers or calcium channel blockers should be pursued in those with AF with RVR who do not undergo cardioversion. Anticoagulation is an important component of management, and several tools (e.g., CHA2DS2-VASc) are available to assist with this decision. Direct oral anticoagulants are the first-line medication class for anticoagulation. Disposition can be challenging, and several risk assessment tools (e.g., RED-AF, AFFORD, and the AFTER (complex, modified, and pragmatic) scores) are available to assist with disposition decisions.

CONCLUSION

An understanding of the recent updates in the literature concerning AF with RVR can assist emergency clinicians in the care of these patients.

Predictive value of high-sensitivity troponin for significant coronary artery disease in new-onset atrial fibrillation with rapid ventricular response

BACKGROUND

High-sensitivity troponin-T (HS-cTnT) levels are often measured in patients presenting with atrial fibrillation (AF), with many subjected to unnecessary invasive assessments. The significance of a normal or mildly raised HS-cTnT in this context is poorly understood. This study aimed to determine the predictive value of HS-cTnT for significant coronary artery disease (CAD) in new AF with rapid ventricular response. We also compared the discriminative ability of HS-cTnT to suspected angina for significant CAD.

METHODS

We examined patients presenting with new AF to two tertiary Irish centers in a defined period. Those included had HS-cTnT taken at presentation and subsequent ischemic evaluation.

RESULTS

Of 5350 cases screened for inclusion, 281 were deemed eligible. Of these, 148 and 133 patients had a positive and negative index HS-cTnT, respectively. Of those with negative HS-cTnT, 13 (9.8%) had significant CAD versus 51 (34.5%) with positive HS-cTnT (P < 0.001). Positive Hs-cTnT status remained significant upon multivariate analysis (OR, 2.9; 95% CI, 1.37-6.14; P = 0.005). A similar model where HS-cTnT was replaced with suspected angina produced an OR of 1.64 (95% CI, 0.75-3.59; P = 0.213). A logistic model determined optimal cutoff value for HS-cTnT to be less than 30 ng/l, producing a negative predictive value of 91.8% and area under the receiver operative curve of 83.36.

CONCLUSION

HS-cTnT exhibits potential as an effective screening biomarker to predict nonsignificant CAD in new rapid AF, allowing more targeted and rationalized ischemic testing. HS-cTnT may also be a more accurate predictor of significant CAD than clinically suspected stable angina.Graphical abstract: http://links.lww.com/MCA/A540.

Cardiac dysfunction and high-sensitive C-reactive protein are associated with troponin T elevation in ischemic stroke: insights from the SICFAIL study

BACKGROUND

Troponin elevation is common in ischemic stroke (IS) patients. The pathomechanisms involved are incompletely understood and comprise coronary and non-coronary causes, e.g. autonomic dysfunction. We investigated determinants of troponin elevation in acute IS patients including markers of autonomic dysfunction, assessed by heart rate variability (HRV) time domain variables.

METHODS

Data were collected within the Stroke Induced Cardiac FAILure (SICFAIL) cohort study. IS patients admitted to the Department of Neurology, Würzburg University Hospital, underwent baseline investigation including cardiac history, physical examination, echocardiography, and blood sampling. Four HRV time domain variables were calculated in patients undergoing electrocardiographic Holter monitoring. Multivariable logistic regression with corresponding odds ratios (OR) and 95% confidence intervals (CI) was used to investigate the determinants of high-sensitive troponin T (hs-TnT) levels ≥14 ng/L.

RESULTS

We report results from 543 IS patients recruited between 01/2014-02/2017. Of those, 203 (37%) had hs-TnT ≥14 ng/L, which was independently associated with older age (OR per year 1.05; 95% CI 1.02-1.08), male sex (OR 2.65; 95% CI 1.54-4.58), decreasing estimated glomerular filtration rate (OR per 10 mL/min/1.73 m2 0.71; 95% CI 0.61-0.84), systolic dysfunction (OR 2.79; 95% CI 1.22-6.37), diastolic dysfunction (OR 2.29; 95% CI 1.29-4.02), atrial fibrillation (OR 2.30; 95% CI 1.25-4.23), and increasing levels of C-reactive protein (OR 1.48 per log unit; 95% CI 1.22-1.79). We did not identify an independent association of troponin elevation with the investigated HRV variables.

CONCLUSION

Cardiac dysfunction and elevated C-reactive protein, but not a reduced HRV as surrogate of autonomic dysfunction, were associated with increased hs-TnT levels in IS patients independent of established cardiovascular risk factors. Registration-URL: https://www.drks.de/drks_web/; Unique identifier: DRKS00011615.

Cardiac troponins: Mechanisms of release and role in healthy and diseased subjects

The cardiac troponins (cTns), cardiac troponin C (cTnC), cTnT, and cTnI are key elements of myocardial apparatus, fixed as protein complex on the thin filament of sarcomere and are involved in the regulation of excitation-contraction coupling of cardiomyocytes in the presence of Ca²⁺ . Circulating cTnT and cTnI (cTns) increase following cardiac tissue necrosis, and they are consolidated biomarkers of acute myocardial infarction (AMI). However, the use of high sensitivity (hs)-immunoassay tests for cTnT and cTnI has made it possible to identify a multitude of other clinical conditions associated with increased circulating levels of cTns. cTns can be measured also in the peripheral circulation of healthy subjects or athletes, suggesting that different mechanisms are involved in the release of cTns in the blood independently of cardiac cell necrosis. In this review, the molecular/cellular mechanisms involved in cTns release in blood and the exploitation of cTnI and cTnT as biomarkers of cardiac adverse events, in addition to cardiac necrosis, are discussed.

Structural Cardiac Abnormalities in Patients with Atrial Fibrillation/Flutter and Myocardial Injury

BACKGROUND

High-sensitivity cardiac troponin (hs-cTnT) is often increased in patients with atrial fibrillation/flutter, portending a poor prognosis. The etiologies for these increases have not been systematically investigated. Our aim was to define prevalence/significance of structural cardiac abnormalities in patients with atrial fibrillation/flutter and high-sensitivity cardiac troponin T (hs-cTnT) increases.

METHODS

This is a retrospective observational cohort study of patients with atrial fibrillation/flutter diagnosis with hs-cTnT measurements, echocardiograms, and coronary angiograms. Myocardial injury was defined as hs-cTnT >10 ng/L for women and >15 ng/L for men. Cases with myocardial injury were adjudicated according to the Fourth Universal Definition of Myocardial Infarction.

RESULTS

Patients with definite causes for increased hs-cTnT (n = 875) were tabulated but not evaluated further; common diagnoses were type 1 myocardial infarction, critical illness, and known heart failure. Of the remaining 401, increased hs-cTnT was present in 336 (84%) patients. Of those, 78% had nonischemic myocardial injury, the remaining (n = 75, 22%) had type 2 myocardial infarction. Patients with elevated hs-cTnT had greater left ventricular mass index, left ventricular filling pressures, and right ventricular systolic pressure. They more frequently had significant coronary artery disease (47% vs 31%, P = .016), especially in type 2 myocardial infarction. With logistic regression, age, sex (F), diabetes, left ventricular mass index, e' medial velocity, and right ventricular systolic pressure were independent determinants of myocardial injury. One-year mortality was higher in patients with myocardial injury.

CONCLUSIONS

Structural heart abnormalities are common in patients with atrial fibrillation/flutter and increased hs-cTnT. Causes of myocardial injury should be elucidated in each patient to craft appropriate therapies.

Chest pain workup in the presence of atrial fibrillation: impacts on troponin testing, myocardial infarction diagnoses, and long-term prognosis

AIMS

Patients presenting to the emergency department (ED) with chest pain require evaluation for acute coronary syndrome (ACS). Atrial fibrillation (AF) can lead to troponin (cTn) elevation in the absence of ACS. There is limited evidence informing the impact of AF on the diagnostic performance of cTn testing for the diagnosis of Type 1 myocardial infarction (T1MI), or the association between AF and long-term outcomes in this context.

METHODS AND RESULTS

This study used the IMPACT and ADAPT study databases to compile a combined cohort of 3496 adults presenting to ED with chest pain between 2007 and 2014, with early cTn testing during ED workup. The mean age was 56.6 years, and 40.2% were female. Outcomes included adjudicated diagnoses for the index admission and mortality to 1-year after presentation. The specificity of initial cTn testing for T1MI diagnosis was lower for patients in AF compared with those not in AF (79.2% vs. 95.4%, P < 0.001), largely due to a relative increase in Type 2 myocardial infarction diagnoses. Sensitivity for T1MI did not differ between patients with or without AF (88.5% vs. 91.5%, P = 0.485). AF was associated with increased 1-year mortality (10.4% vs. 2.3%, P < 0.001), although this was not significant on multivariable analysis.

CONCLUSION

The specificity of serial cTn testing for the diagnosis of T1MI in patients presenting to ED with chest pain is reduced in the presence of AF. Further studies are needed to establish whether optimised cTn thresholds for patients with AF can improve workup and outcomes.

Transfusion in Older Anemic Patients: Should the Troponin Value Be Taken into Account?

BACKGROUND

Anemia is common in older individuals, but it is not known whether the prognostic impact of transfusion differs according to cardiac troponin concentration.

METHODS

During this 2-year retrospective study in an acute geriatric unit, 514 patients with hemoglobin <10 g/dL and troponin sampling were included. Thirty-day and 1-year mortality were compared according to transfusion status and troponin and hemoglobin levels.

RESULTS

Of the 514 anemic patients included (median age 88 years), 157 (31%) had elevated troponin concentrations. These patients were more likely to die at 30 days (49% vs 27%, P < .001) and 1 year (65% vs 51%, P = .004) than patients with normal values. Among patients with elevated troponin concentrations, 30-day mortality tended to be lower in transfused than in not-transfused patients (hazard ratio 0.48; 95% confidence interval, 0.21-1.08; P = .07). This association was not found in patients without troponin elevation (hazard ratio 1.09; 95% CI, 0.61-1.93; P = .8). Transfusion was associated with 30-day survival in patients with hemoglobin ≤8 g/dL. It was also associated with excess 1-year mortality in patients with hemoglobin >8 g/dL.

CONCLUSIONS

This pilot study suggests that transfusion could be associated with better 30-day outcomes in older anemic patients with anemia-related myocardial injury. Thus, troponin levels could be involved in decision-making relative to transfusion in anemic older patients. Clinical trials are needed to establish the benefit of transfusion in patients with elevated troponins.

Prognostic Significance of Ventricular Arrhythmias in 13 444 Patients With Acute Coronary Syndrome: A Retrospective Cohort Study Based on Routine Clinical Data (NIHR Health Informatics Collaborative VA-ACS Study)

Background A minority of acute coronary syndrome (ACS) cases are associated with ventricular arrhythmias (VA) and/or cardiac arrest (CA). We investigated the effect of VA/CA at the time of ACS on long-term outcomes. Methods and Results We analyzed routine clinical data from 5 National Health Service trusts in the United Kingdom, collected between 2010 and 2017 by the National Institute for Health Research Health Informatics Collaborative. A total of 13 444 patients with ACS, 376 (2.8%) of whom had concurrent VA, survived to hospital discharge and were followed up for a median of 3.42 years. Patients with VA or CA at index presentation had significantly increased risks of subsequent VA during follow-up (VA group: adjusted hazard ratio [HR], 4.15 [95% CI, 2.42-7.09]; CA group: adjusted HR, 2.60 [95% CI, 1.23-5.48]). Patients who suffered a CA in the context of ACS and survived to discharge also had a 36% increase in long-term mortality (adjusted HR, 1.36 [95% CI, 1.04-1.78]), although the concurrent diagnosis of VA alone during ACS did not affect all-cause mortality (adjusted HR, 1.03 [95% CI, 0.80-1.33]). Conclusions Patients who develop VA or CA during ACS who survive to discharge have increased risks of subsequent VA, whereas those who have CA during ACS also have an increase in long-term mortality. These individuals may represent a subgroup at greater risk of subsequent arrhythmic events as a result of intrinsically lower thresholds for developing VA.

Mortality risk prediction of high-sensitivity C-reactive protein in suspected acute coronary syndrome: A cohort study

BACKGROUND

There is limited evidence on the use of high-sensitivity C-reactive protein (hsCRP) as a biomarker for selecting patients for advanced cardiovascular (CV) therapies in the modern era. The prognostic value of mildly elevated hsCRP beyond troponin in a large real-world cohort of unselected patients presenting with suspected acute coronary syndrome (ACS) is unknown. We evaluated whether a mildly elevated hsCRP (up to 15 mg/L) was associated with mortality risk, beyond troponin level, in patients with suspected ACS.

METHODS AND FINDINGS

We conducted a retrospective cohort study based on the National Institute for Health Research Health Informatics Collaborative data of 257,948 patients with suspected ACS who had a troponin measured at 5 cardiac centres in the United Kingdom between 2010 and 2017. Patients were divided into 4 hsCRP groups (<2, 2 to 4.9, 5 to 9.9, and 10 to 15 mg/L). The main outcome measure was mortality within 3 years of index presentation. The association between hsCRP levels and all-cause mortality was assessed using multivariable Cox regression analysis adjusted for age, sex, haemoglobin, white cell count (WCC), platelet count, creatinine, and troponin. Following the exclusion criteria, there were 102,337 patients included in the analysis (hsCRP <2 mg/L (n = 38,390), 2 to 4.9 mg/L (n = 27,397), 5 to 9.9 mg/L (n = 26,957), and 10 to 15 mg/L (n = 9,593)). On multivariable Cox regression analysis, there was a positive and graded relationship between hsCRP level and mortality at baseline, which remained at 3 years (hazard ratio (HR) (95% CI) of 1.32 (1.18 to 1.48) for those with hsCRP 2.0 to 4.9 mg/L and 1.40 (1.26 to 1.57) and 2.00 (1.75 to 2.28) for those with hsCRP 5 to 9.9 mg/L and 10 to 15 mg/L, respectively. This relationship was independent of troponin in all suspected ACS patients and was further verified in those who were confirmed to have an ACS diagnosis by clinical coding. The main limitation of our study is that we did not have data on underlying cause of death; however, the exclusion of those with abnormal WCC or hsCRP levels >15 mg/L makes it unlikely that sepsis was a major contributor.

CONCLUSIONS

These multicentre, real-world data from a large cohort of patients with suspected ACS suggest that mildly elevated hsCRP (up to 15 mg/L) may be a clinically meaningful prognostic marker beyond troponin and point to its potential utility in selecting patients for novel treatments targeting inflammation.

TRIAL REGISTRATION

ClinicalTrials.gov - NCT03507309.

Biomarkers in Atrial Fibrillation: Pathogenesis and Clinical Implications

Biomarkers derived from the key components of the pathophysiology of atrial fibrillation (AF) and its complications have the potential to play an important role in earlier characterization of AF phenotype and in risk prediction of adverse clinical events, which may translate into improved management strategies. C-reactive protein, natriuretic peptides, cardiac troponins, growth differentiation factor-15, and fibroblast growth factor-23 have been shown to be the most promising biomarkers in AF. Some biomarkers have already been included in clinical risk scores to predict postoperative AF, thromboembolism, major bleeding, and death. Considerably more work is needed to bring these novel biomarkers into routine clinical management of patients with AF.

Prognostic value of troponin I in atrial fibrillation

OBJECTIVE

To evaluate whether circulating cardiac troponin I (cTnI) levels are associated with worst outcomes in patients with atrial fibrillation (AF).

METHODS

Consecutive patients visiting the emergency room (ER) with a new episode of a previously diagnosed AF or a new diagnosis of AF during ER admission between January 1st, 2010 and December 31st, 2015, were enrolled in the study (n = 2617). After applying exclusion criteria and eliminating repeated episodes, 2013 patients were finally included. Of these, 1080 patients with at least one cTnI measurement in the ER were selected and classified into 4 groups according to cTnI quartiles: Q1 (n = 147) cTnI <10 ng/L (Group 1); Q2 (n = 254): 10-19 ng/L (Group 2); Q3 (n = 409): 20-40 ng/L (Group 3); and Q4 (n = 270): cTnI >40 ng/L (Group 4). The median follow-up period was 47.8 ± 32.8 months. The primary endpoint was all-cause death during the follow-up.

RESULTS

A higher mortality was found in group 4 compared with the other groups (58.9% vs. 28.5%, respectively, p < 0.001), along with, hospitalizations (40.4% vs. 30.7%, p = 0.004), and readmissions due to decompensated heart failure (26.7% vs. 2.5%, p = 0.002). The probability of survival without AF recurrences was lower in the Q4 (p = 0.045). Moreover, cTnI levels >40 ng/L (Q4) were an independent risk factor of death (HR, 2.03; 95% CI, 1.64-2.51; p < 0.001).

CONCLUSION

The assessment of cTnI at ER admission could be a useful strategy for risk stratification of patients diagnosed with AF by identifying a subgroup with medium-term to long-term increased risk of adverse events and mortality.

Prospective multicentric validation of a novel prediction model for paroxysmal atrial fibrillation

Background

The early recognition of paroxysmal atrial fibrillation (pAF) is a major clinical challenge for preventing thromboembolic events. In this prospective and multicentric study we evaluated prediction scores for the presence of pAF, calculated from non-invasive medical history and echocardiographic parameters, in patients with unknown AF status.

Methods

The 12-parameter score with parameters age, LA diameter, aortic root diameter, LV,ESD, TDI Aʹ, heart frequency, sleep apnea, hyperlipidemia, type II diabetes, smoker, ß-blocker, catheter ablation, and the 4-parameter score with parameters age, LA diameter, aortic root diameter and TDI A’ were tested. Presence of pAF was verified by continuous electrocardiogram (ECG) monitoring for up to 21 days in 305 patients.

Results

The 12-parameter score correctly predicted pAF in all 34 patients, in which pAF was newly detected by ECG monitoring. The 12- and 4-parameter scores showed sensitivities of 100% and 82% (95%-CI 65%, 93%), specificities of 75% (95%-CI 70%, 80%) and 67% (95%-CI 61%, 73%), and areas under the receiver operating characteristic (ROC) curves of 0.84 (95%-CI 0.80, 0.88) and 0.81 (95%-CI 0.74, 0.87). Furthermore, properties of AF episodes and durations of ECG monitoring necessary to detect pAF were analysed.

Conclusions

The prediction scores adequately detected pAF using variables readily available during routine cardiac assessment and echocardiography. The model scores, denoted as ECHO-AF scores, represent simple, highly sensitive and non-invasive tools for detecting pAF that can be easily implemented in the clinical practice and might serve as screening test to initiate further diagnostic investigations for validating the presence of pAF.

Graphic abstract

Prospective validation of a novel prediction model for paroxysmal atrial fibrillation based on echocardiography and medical history parameters by long-term Holter ECG

Electronic supplementary material

The online version of this article (10.1007/s00392-020-01773-z) contains supplementary material, which is available to authorized users.

Invasive versus non-invasive management of older patients with non-ST elevation myocardial infarction (SENIOR-NSTEMI): a cohort study based on routine clinical data

BACKGROUND

Previous trials suggest lower long-term risk of mortality after invasive rather than non-invasive management of patients with non-ST elevation myocardial infarction (NSTEMI), but the trials excluded very elderly patients. We aimed to estimate the effect of invasive versus non-invasive management within 3 days of peak troponin concentration on the survival of patients aged 80 years or older with NSTEMI.

METHODS

Routine clinical data for this study were obtained from five collaborating hospitals hosting NIHR Biomedical Research Centres in the UK (all tertiary centres with emergency departments). Eligible patients were 80 years old or older when they underwent troponin measurements and were diagnosed with NSTEMI between 2010 (2008 for University College Hospital) and 2017. Propensity scores (patients' estimated probability of receiving invasive management) based on pretreatment variables were derived using logistic regression; patients with high probabilities of non-invasive or invasive management were excluded. Patients who died within 3 days of peak troponin concentration without receiving invasive management were assigned to the invasive or non-invasive management groups based on their propensity scores, to mitigate immortal time bias. We estimated mortality hazard ratios comparing invasive with non-invasive management, and compared the rate of hospital admissions for heart failure.

FINDINGS

Of the 1976 patients with NSTEMI, 101 died within 3 days of their peak troponin concentration and 375 were excluded because of extreme propensity scores. The remaining 1500 patients had a median age of 86 (IQR 82-89) years of whom (845 [56%] received non-invasive management. During median follow-up of 3·0 (IQR 1·2-4·8) years, 613 (41%) patients died. The adjusted cumulative 5-year mortality was 36% in the invasive management group and 55% in the non-invasive management group (adjusted hazard ratio 0·68, 95% CI 0·55-0·84). Invasive management was associated with lower incidence of hospital admissions for heart failure (adjusted rate ratio compared with non-invasive management 0·67, 95% CI 0·48-0·93).

INTERPRETATION

The survival advantage of invasive compared with non-invasive management appears to extend to patients with NSTEMI who are aged 80 years or older.

FUNDING

NIHR Imperial Biomedical Research Centre, as part of the NIHR Health Informatics Collaborative.

Prognostic significance of troponin level in 3121 patients presenting with atrial fibrillation (The NIHR Health Informatics Collaborative TROP-AF study)

Background Patients presenting with atrial fibrillation (AF) often undergo a blood test to measure troponin, but interpretation of the result is impeded by uncertainty about its clinical importance. We investigated the relationship between troponin level, coronary angiography, and all-cause mortality in real-world patients presenting with AF. Methods and Results We used National Institute of Health Research Health Informatics Collaborative data to identify patients admitted between 2010 and 2017 at 5 tertiary centers in the United Kingdom with a primary diagnosis of AF. Peak troponin results were scaled as multiples of the upper limit of normal. A total of 3121 patients were included in the analysis. Over a median follow-up of 1462 (interquartile range, 929-1975) days, there were 586 deaths (18.8%). The adjusted hazard ratio for mortality associated with a positive troponin (value above upper limit of normal) was 1.20 (95% CI, 1.01-1.43; P<0.05). Higher troponin levels were associated with higher risk of mortality, reaching a maximum hazard ratio of 2.6 (95% CI, 1.9-3.4) at ≈250 multiples of the upper limit of normal. There was an exponential relationship between higher troponin levels and increased odds of coronary angiography. The mortality risk was 36% lower in patients undergoing coronary angiography than in those who did not (adjusted hazard ratio, 0.61; 95% CI, 0.42-0.89; P=0.01). Conclusions Increased troponin was associated with increased risk of mortality in patients presenting with AF. The lower hazard ratio in patients undergoing invasive management raises the possibility that the clinical importance of troponin release in AF may be mediated by coronary artery disease, which may be responsive to revascularization.