Development of the Canadian Syncope Risk Score to predict serious adverse events after emergency department assessment of syncope

Syncope in the Emergency Department: A Guide for Clinicians

Syncope is a common presenting symptom to emergency departments, but its evaluation and initial management can be challenging for ED practitioners and particularly urgent in the presence of high-risk features that increase the likelihood of cardiac etiology. Even after thorough clinical evaluation, syncope may remain unexplained. In such instances, practitioners' clinical judgment and risk assessments are critical to guide further management. In this article, evidence-informed strategies are outlined to approach the diagnosis of syncope and provide an overview of syncope clinical decision rules and shared decision-making. By incorporating risk stratification and shared decision-making into syncope care, practitioners can more confidently engage patients and families in disposition decisions to organize appropriate outpatient and follow-up care, observation, or admission.

Head-up tilt test diagnostic yield in syncope diagnosis

BACKGROUND

The European Syncope Guidelines (ESG) recommend the use of Head-up tilt test (HUT) in case of suspicion of vasovagal syncope (VVS) or orthostatic hypotensive syncope (OHS) after an adequate initial inconclusive evaluation. We report a single center experience in the scenario of suspected VVS or OHS, who underwent HUT in patients referred to a Syncope Clinic after ruling out high-risk causes.

METHODS

We prospectively and consecutively included all syncopal patients that were referred for HUT, by their attending physician after performing a series of diagnostic tests to rule out cardiac etiology. The clinical history and diagnostic tests performed were reviewed prior to HUT. Patients were pre-classified according to the recommendations from the ESG as; VVS, OHS or Syncope of Unknown Etiology (SUE).

RESULTS

We studied 1058 patients, 558 (52.7%) males, mean age 46.5 ± 20.1 yr. There were no gender differences in age, risk factors, previous heart diseases, ECG findings or number of previous tests. Based on the ESG criteria a significant number of diagnostic tests were probably unnecessarily performed. HUT was positive in 609 patients (57.5%). The rate of positive HUT according to pre-classification was significantly different among groups: 60% VVS, 46.1% OHS and 54.3% SUE (p = 0.037). Combining ESG recommendations and HUT results of the 1058 resulted in 762 (72%) diagnosed as VVS, 89 (8.4%) as OHS and 207 (19.5%) as SUE.

CONCLUSIONS

Appropriate application of ESG recommendations combined with HUT, identified 81% of patients with non-cardiogenic syncope, potentially avoiding a significant number of unnecessary diagnostic tests.

Benefit of hospital admission for detecting serious adverse events among emergency department patients with syncope: a propensity-score-matched analysis of a multicentre prospective cohort

BACKGROUND

The benefit of hospital admission after emergency department evaluation for syncope is unclear. We sought to determine the association between hospital admission and detection of serious adverse events, and whether this varied according to the Canadian Syncope Risk Score (CSRS).

METHODS

We conducted a secondary analysis of a multicentre prospective cohort of patients assessed in the emergency department for syncope. We compared patients admitted to hospital and discharged patients, using propensity scores to match 1:1 for risk of a serious adverse event. The primary outcome was detection of a serious adverse event in hospital for admitted patients or within 30 days after emergency department disposition for discharged patients.

RESULTS

We included 8183 patients, of whom 743 (9.1%) were admitted; 658/743 (88.6%) were matched. Admitted patients had higher odds of detection of a serious adverse event (odds ratio [OR] 5.0, 95% confidence interval [CI] 3.3-7.4), nonfatal arrhythmia (OR 5.1, 95% CI 2.9-8.8) and nonarrhythmic serious adverse event (OR 6.3, 95% CI 2.9-13.5). There were no significant differences between the 2 groups in death (OR 1.0, 95% CI 0.4-2.7) or detection of ventricular arrhythmia (OR 2.0, 95% CI 0.7-6.0). Differences between admitted and discharged patients in detection of serious adverse events were greater for those with a CSRS indicating medium to high risk (p = 0.04).

INTERPRETATION

Patients with syncope were more likely to have serious adverse events identified within 30 days if they were admitted to hospital rather than discharged from the emergency department. However, the benefit of hospital admission is low for patients at low risk of a serious adverse event.

Shared Decision Making for Syncope in the Emergency Department: A Randomized Controlled Feasibility Trial

OBJECTIVES

Significant practice variation is seen in the management of syncope in the emergency department (ED). We sought to evaluate the feasibility of performing a randomized controlled trial of a shared decision making (SDM) tool for low-to-intermediate-risk syncope patients presenting to the ED.

METHODS

We performed a randomized controlled trial of adults (≥30 years) with unexplained syncope who presented to an academic ED in the United States. Patients with a serious diagnosis identified in the ED were excluded. Patients were randomized, 1:1, to receive either usual care or a personalized syncope decision aid (SynDA) meant to facilitate SDM. Our primary outcome was feasibility, i.e., ability to enroll 50 patients in 24 months. Secondary outcomes included patient knowledge, involvement (measured with OPTION-5), rating of care, and clinical outcomes at 30 days post-ED visit.

RESULTS

After screening 351 patients, we enrolled 50 participants with unexplained syncope from January 2017 to January 2019. The most common reason for exclusion was lack of clinical equipoise to justify SDM (n = 124). Patients in the SynDA arm tended to have greater patient involvement, as shown by higher OPTION-5 scores: 52/100 versus 27/100 (between-group difference = -25.4, 95% confidence interval = -13.5 to -37.3). Both groups had similar levels of clinical knowledge, ratings of care, and serious clinical outcomes at 30 days.

CONCLUSIONS

Among ED patients with unexplained syncope, a randomized controlled trial of a shared decision-making tool is feasible. Although this study was not powered to detect differences in clinical outcomes, it demonstrates feasibility, while providing key lessons and effect sizes that could inform the design of future SDM trials.

Canadian Cardiovascular Society Clinical Practice Update on the Assessment and Management of Syncope

Syncope is a symptom that occurs in multiple settings and has a variety of underlying causes, ranging from benign to life threatening. Determining the underlying diagnosis and prognosis can be challenging and often results in an unstructured approach to evaluation, which is ineffective and costly. In this first ever document, the Canadian Cardiovascular Society (CCS) provides a clinical practice update on the assessment and management of syncope. It highlights similarities and differences between the 2017 American College of Cardiology/American Heart Association/Heart Rhythm Society and the 2018 European Society of Cardiology guidelines, draws on new data following a thorough review of medical literature, and takes the best available evidence and clinical experience to provide clinical practice tips. Where appropriate, a focus on a Canadian perspective is emphasized in order to illuminate larger international issues. This document represents the consensus of a Canadian panel comprised of multidisciplinary experts on this topic with a mandate to formulate disease-specific advice. The primary writing panel wrote the document, followed by peer review from the secondary writing panel. The CCS Guidelines Committee reviewed and approved the statement. The practice tips represent the consensus opinion of the primary writing panel authors, endorsed by the CCS. The CCS clinical practice update on the assessment and management of syncope focuses on epidemiology, the initial evaluation including risk stratification and disposition from the emergency department, initial diagnostic work-up, management of vasovagal syncope and orthostatic hypotension, and syncope and driving.

Identifying Guideline-Practice Gaps to Optimize Evaluation and Management for Patients With Syncope

Syncope is a common and complex symptom that requires efficient evaluation to determine the cause. Recent guidelines focus on high-value testing, but a systematic evaluation of their implementation has not been performed. To this end, we used a mixed-methods approach of surveys, chart reviews, and focus groups to understand current practices relating to the diagnosis and management of patients with syncope and to identify barriers and facilitators to the implementation of guideline-supported recommendations. Surveys were distributed to 1500 providers in the specialties of hospital medicine, cardiology, emergency medicine, and family medicine, and 175 responses were received. Knowledge of class I and III guideline recommendations were assessed with the use of clinical vignettes, which were answered correctly 60%-80% of the time. Chart reviews focused on patient history and testing for syncope. Per the guidelines, < 50% of charts met criteria for bare minimum history and physical examination. Based on the documentation, 25% of echocardiograms and 90% of neurologic testing obtained would not have been appropriate per the guidelines. Self-reported and actual practice patterns were similar in rates of testing. Our results indicate that there remains a gap between guideline-directed management and actual practice for syncope. Focus groups revealed barriers across multiple levels of care that need to be addressed to improve care. Our findings emphasize the need for proactive strategies to improve syncope testing practices, potentially saving millions of dollars in the health care system.

Does N-Terminal Pro-B-Type Natriuretic Peptide Improve the Risk Stratification of Emergency Department Patients With Syncope?

BACKGROUND

Studies have reported that natriuretic peptides provide prognostic information for emergency department (ED) syncope.

OBJECTIVE

To evaluate whether adding N-terminal pro-B-type natriuretic peptide (NT-proBNP) to the Canadian Syncope Risk Score (CSRS) improves prediction of 30-day serious adverse events (SAEs).

DESIGN

Prospective cohort study.

SETTING

6 EDs in 2 Canadian provinces.

PARTICIPANTS

1452 adult ED patients with syncope.

INTERVENTION

Serum NT-proBNP was measured locally at 1 site and batch processed at a central laboratory from other sites. The concentrations were not available to treating physicians or for adjudication of outcomes.

MEASUREMENTS

An adjudicated composite outcome of 30-day SAEs, including death and cardiac (arrhythmic and nonarrhythmic) and noncardiac events.

RESULTS

Of 1452 patients enrolled, 152 (10.5% [95% CI, 9.0% to 12.1%]) had 30-day SAEs, 57 (3.9%) of which were identified after the index ED disposition. Serum NT-proBNP concentrations were significantly higher among patients with SAEs than those without them (median, 626.5 ng/L vs. 81 ng/L; P < 0.001). Adding NT-proBNP values to the CSRS did not significantly improve prognostication (c-statistic, 0.89 and 0.90; P = 0.12 for difference), regardless of SAE subgroup or whether the SAE was identified after the index ED visit. The net reclassification index shows that NT-proBNP would have correctly reclassified 3% of patients with SAEs at the expense of incorrectly reclassifying 2% of patients without SAEs.

LIMITATIONS

Our study was powered to detect a 3% difference in the area under the curve. The heterogeneity of outcomes and robust baseline discrimination by the CSRS will make improvements challenging.

CONCLUSION

Although serum NT-proBNP concentrations were generally much higher among ED patients with syncope who had a 30-day SAE, this blood test added little new information to the CSRS. Routine use of NT-proBNP for ED syncope prognostication is not recommended.

PRIMARY FUNDING SOURCE

Physicians' Services Incorporated Foundation, Canadian Institutes of Health Research, and The Ottawa Hospital Academic Medical Organization.

EGSYS score for the prediction of cardiac etiology in syncope: Is it useful in an outpatient setting?

INTRODUCTION

The EGSYS score uses clinical variables to predict which patients may have cardiac (CS) or non-cardiac syncope (NCS) and has been validated in the emergency department setting. This study aims to determine whether the score has the same applicability in an outpatient setting.

METHODS

In this retrospective study of all patients observed in the outpatient setting of a hospital with a syncope unit between January 2015 and December 2016, the EGSYS score was calculated for each patient, and its sensitivity and specificity were determined for the prediction of CS in patients with score ≥3.

RESULTS

A total of 224 patients, mean age 64.3±21.7 years, 116 (51.8%) male, were analyzed. In the 163 (72.7%) patients with confirmed syncope, CS was diagnosed in 27 (16.6%) and NCS in 136 (83.4%). The EGSYS score was ≥3 in 40 (20.0%) patients with NCS and in 13 (48.1%) with CS. A positive score had a sensitivity of 48.2% (95% CI: 28.7-68.1), a specificity of 77.9% (95% CI: 70.0-84.6), and a positive and negative predictive value of 30.2% (95% CI: 20.8-41.8) and 88.3% (95% CI: 83.9-91.7), respectively.

CONCLUSION

The EGSYS score has limited usefulness in an outpatient setting, where observed patients have already been been medically assessed. Given its high specificity and negative predictive value, it may be useful to reassure low-risk patients and family members.

Multicenter Emergency Department Validation of the Canadian Syncope Risk Score

IMPORTANCE

The management of patients with syncope in the emergency department (ED) is challenging because no robust risk tool available has been recommended for clinical use.

OBJECTIVE

To validate the Canadian Syncope Risk Score (CSRS) in a new cohort of patients with syncope to determine its ability to predict 30-day serious outcomes not evident during index ED evaluation.

DESIGN, SETTING, AND PARTICIPANTS

This prospective multicenter cohort study conducted at 9 EDs across Canada included patients 16 years and older who presented to EDs within 24 hours of syncope. Patients were enrolled from March 2014 to April 2018.

MAIN OUTCOMES AND MEASURES

Baseline characteristics, CSRS predictors, and 30-day adjudicated serious outcomes, including arrhythmic (arrhythmias, interventions for arrhythmia, or unknown cause of death) and nonarrhythmic (myocardial infarction, structural heart disease, pulmonary embolism, or hemorrhage) serious outcomes, were collected. Calibration and discrimination characteristics for CSRS validation were calculated.

RESULTS

A total of 3819 patients were included (mean [SD] age 53.9 [22.8] years; 2088 [54.7%] female), of whom 139 (3.6%) experienced 30-day serious outcomes, including 13 patients (0.3%) who died. In the validation cohort, there were no differences between the predicted and observed risk, the calibration slope was 1.0, and the area under the receiver operating characteristic curve was 0.91 (95% CI, 0.88-0.93). The empirical probability of a 30-day serious outcome during validation was 3.64% (95% CI, 3.09%-4.28%) compared with the model-predicted probability of 3.17% (95% CI, 2.66%-3.77%; P = .26). The proportion of patients with 30-day serious outcomes increased from 3 of 1631 (0.3%) in the very-low-risk group to 40 of 78 (51.3%) in the very-high-risk group (Cochran-Armitage trend test P < .001). There was a similar significant increase in the serious outcome subtypes with increasing CSRS risk category. None of the very-low-risk and low-risk patients died or experienced ventricular arrhythmia. At a threshold score of -1 (2145 of 3819 patients), the CSRS sensitivity and specificity were 97.8% (95% CI, 93.8%-99.6%) and 44.3% (95% CI, 42.7%-45.9%), respectively.

CONCLUSIONS AND RELEVANCE

The CSRS was successfully validated and its use is recommended to guide ED management of patients when serious causes are not identified during index ED evaluation. Very-low-risk and low-risk patients can generally be discharged, while brief hospitalization can be considered for high-risk patients. We believe CSRS implementation has the potential to improve patient safety and health care efficiency.

Twelve-Year Temporal Trends in Ambulance Use for Patients Hospitalized With a Primary Diagnosis of Syncope in Canada

Background

Ambulance use is a costly mode of transportation to the emergency department (ED). Syncope is a frequent presentation to the ED; however, no data exist regarding the proportion of hospitalized patients with syncope arriving by ambulance and their outcomes compared with self-presenters.

Methods

The Canadian Institute for Health Information database was used to identify patients aged > 20 years hospitalized with a primary diagnosis of syncope (International Classification of Diseases 10th Revision code R55) in Canada, except Quebec, between April 2004 and March 2016. Logistic regression models (odds ratio and 95% confidence interval) were used to identify demographics, clinical factors, and province associated with ambulance use and whether ambulance use was associated with in-hospital mortality.

Results

Among 108,967 syncope hospitalizations, 64% of patients arrived by ambulance, and use increased from 58.8% to 66.1% over 12 years (P for trend < 0.01). Significant variations existed in ambulance use across provinces (P < 0.01). Predictors associated with higher odds of ambulance use were increasing age, male sex, urban residence, residing in areas with lower annual household income, and higher comorbidity burden. In multivariable-adjusted analysis, ambulance use was associated with a 1.7-fold higher odds of in-hospital mortality.

Conclusions

Approximately two-thirds of patients hospitalized for syncope presented by ambulance, and use has increased over time. Hospitalized patients in syncope who are transported by ambulance have a worse prognosis. Further research on emergency medical services’ risk stratification of patients who are transported by ambulance may help to identify a low-risk population who may obviate the need for transport.

Role of Biomarkers in the Prediction of Serious Adverse Events after Syncope in Prehospital Assessment: A Multi-Center Observational Study

Syncope is defined as the nontraumatic, transient loss of awareness of rapid onset, short duration and with complete spontaneous recovery, and accounts for 1%–3% of all visits to the emergency department. The objective of this study was to evaluate the predictive capacity of the National Early Warning Score 2 (NEWS2) and prehospital lactate (pLA), individually and combined, at the prehospital level to detect patients with syncope at risk of early mortality (within 48 h) in the hospital environment. A prospective, multicenter cohort study without intervention was carried out on syncope patients aged over 18 who were given advanced life support and taken to the hospital. Our study included a total of 361 cases. Early mortality affected 21 patients (5.8%). The combined score formed by the NEWS2 and the pLA (NEWS2-L) obtained an AUC of 0.948 (95% CI: 0.88–1) and an odds ratio of 86.25 (95% CI: 11.36–645.57), which is significantly higher than that obtained by the NEWS2 or pLA in isolation (p = 0.018). The NEWS2-L can help stratify the risk in patients with syncope treated in the prehospital setting, with only the standard measurement of physiological parameters and pLA.

Syncope in the Emergency Department

Syncope is a common presentation to Emergency Departments (EDs). Estimates on the frequency of visits (0.6–1.7%) and subsequent rates of hospitalizations (12–85%) vary according to country. The initial ED evaluation for syncope consists of a detailed history, physical examination and 12-lead electrocardiogram (ECG). The use of additional diagnostic testing and specialist evaluation should be based on this initial evaluation rather than an unstructured approach of broad-based testing. Risk stratification performed in the ED is important for estimating prognosis, triage decisions and to establish urgency of any further work-up. The primary approach to risk stratification focuses on identifying high- and low-risk predictors. The use of prediction tools may be used to aid in physician decision-making; however, they have not performed better than the clinical judgment of emergency room physicians. Following risk stratification, decision for hospitalization should be based on the seriousness of the underlying cause for syncope or based on high-risk features, or the severity of co-morbidities. For those deemed intermediate risk, access to specialist assessment and related testing may occur in a syncope unit in the emergency department, as an outpatient, or in a less formal care pathway and is highly dependent on the local healthcare system. For syncope patients presenting to the ED, ~0.8% die and 10.3% suffer a non-fatal severe outcome within 30 days.

Orthostatic vital signs do not predict 30 day serious outcomes in older emergency department patients with syncope: A multicenter observational study

BACKGROUND

Syncope is a common chief complaint among older adults in the Emergency Department (ED), and orthostatic vital signs are often a part of their evaluation. We assessed whether abnormal orthostatic vital signs in the ED are associated with composite 30-day serious outcomes in older adults presenting with syncope.

METHODS

We performed a secondary analysis of a prospective, observational study at 11 EDs in adults ≥ 60 years who presented with syncope or near syncope. We excluded patients lost to follow up. We used the standard definition of abnormal orthostatic vital signs or subjective symptoms of lightheadedness upon standing to define orthostasis. We determined the rate of composite 30-day serious outcomes, including those during the index ED visit, such as cardiac arrhythmias, myocardial infarction, cardiac intervention, new diagnosis of structural heart disease, stroke, pulmonary embolism, aortic dissection, subarachnoid hemorrhage, cardiopulmonary resuscitation, hemorrhage/anemia requiring transfusion, with major traumatic injury from fall, recurrent syncope, and death) between the groups with normal and abnormal orthostatic vital signs.

RESULTS

The study cohort included 1974 patients, of whom 51.2% were male and 725 patients (37.7%) had abnormal orthostatic vital signs. Comparing those with abnormal to those with normal orthostatic vital signs, we did not find a difference in composite 30-serious outcomes (111/725 (15.3%) vs 184/1249 (14.7%); unadjusted odds ratio, 1.05 [95%CI, 0.81-1.35], p = 0.73). After adjustment for gender, coronary artery disease, congestive heart failure (CHF), history of arrhythmia, dyspnea, hypotension, any abnormal ECG, physician risk assessment, medication classes and disposition, there was no association with composite 30-serious outcomes (adjusted odds ratio, 0.82 [95%CI, 0.62-1.09], p = 0.18).

CONCLUSIONS

In a cohort of older adult patients presenting with syncope who were able to have orthostatic vital signs evaluated, abnormal orthostatic vital signs did not independently predict composite 30-day serious outcomes.

Risk Stratification of Older Adults Who Present to the Emergency Department With Syncope: The FAINT Score

STUDY OBJECTIVE

Older adults with syncope are commonly treated in the emergency department (ED). We seek to derive a novel risk-stratification tool to predict 30-day serious cardiac outcomes.

METHODS

We performed a prospective, observational study of older adults (≥60 years) with unexplained syncope or near syncope who presented to 11 EDs in the United States. Patients with a serious diagnosis identified in the ED were excluded. We collected clinical and laboratory data on all patients. Our primary outcome was 30-day all-cause mortality or serious cardiac outcome.

RESULTS

We enrolled 3,177 older adults with unexplained syncope or near syncope between April 2013 and September 2016. Mean age was 73 years (SD 9.0 years). The incidence of the primary outcome was 5.7% (95% confidence interval [CI] 4.9% to 6.5%). Using Bayesian logistic regression, we derived the FAINT score: history of heart failure, history of cardiac arrhythmia, initial abnormal ECG result, elevated pro B-type natriuretic peptide, and elevated high-sensitivity troponin T. A FAINT score of 0 versus greater than or equal to 1 had sensitivity of 96.7% (95% CI 92.9% to 98.8%) and specificity 22.2% (95% CI 20.7% to 23.8%), respectively. The FAINT score tended to be more accurate than unstructured physician judgment: area under the curve 0.704 (95% CI 0.669 to 0.739) versus 0.630 (95% CI 0.589 to 0.670).

CONCLUSION

Among older adults with syncope or near syncope of potential cardiac cause, a FAINT score of zero had a reasonably high sensitivity for excluding death and serious cardiac outcomes at 30 days. If externally validated, this tool could improve resource use for this common condition.

Temporary loss of consciousness during cetuximab treatment of a patient with metastatic colon cancer: a case report

BACKGROUND

Anti-epidermal growth factor receptor (EGFR) antibody is widely used for the treatment of patients with metastatic colorectal cancer. Hypomagnesemia is a comparatively frequent adverse event of this drug, which is likely overlooked because it occurs later in treatment without symptoms. Furthermore, hypomagnesemia and hypomagnesemia-induced corrected QT (QTc) prolongation may lead to loss of consciousness (LOC), the onset of which is not generally considered associated with the treatment of anti-EGFR antibody because of its rare occurrence. Here, we present a colorectal cancer patient treated with anti-EGFR antibody, who suffered LOC during treatment while severe hypomagnesemia or QTc prolongation was not observed.

CASE PRESENTATION

A 69-year-old man with metastatic colon cancer was treated with cetuximab (anti-EGFR antibody) plus irinotecan as third-line chemotherapy. His serum magnesium level gradually decreased, and grade 2 hypomagnesemia (a serum magnesium level of 0.9 mg/dL) was observed at the 12th administration of cetuximab. In light of this development, intravenous supplementation of 20 mEq magnesium sulfate began with careful blood monitoring despite the lack of clinical symptoms. Electrocardiogram (ECG) showed prolonged QT or corrected QT (QTc) intervals (grade 1). His serum magnesium level remained at 0.9 mg/dL, and no hypomagnesemia symptoms were observed by the 17th administration of cetuximab. After the treatment, however, he suddenly lost consciousness without symptoms related to infusion or allergic reactions. Circulatory collapse following dermatological reactions and respiratory events were not evident. Intravenous supplementation of magnesium sulfate was administered again. He awakened 2 min after the onset of temporary LOC without any other symptoms related to hypomagnesemia, such as lethargy, tremor, tetany, and seizures. No other etiology outside of the low level of serum magnesium was confirmed in further examinations. Cetuximab was discontinued, and his serum magnesium level returned to a level within the normal range after 6 weeks. Because of tumor progression, regorafenib and TAS-102 (trifluridine tipiracil hydrochloride) were introduced sequentially for 6 months. Five months after the final treatment of TAS-102, he died of his primary disease, which reflected a survival period of 4 years and 6 months since the beginning of treatment.

CONCLUSIONS

This case report reminds clinicians that LOC can be induced without severe hypomagnesemia or QTc prolongation, during anti-EGFR antibody treatment for metastatic colorectal cancer even while under carefully monitored magnesium supplementation.

Prevalence and Predictors of Pulmonary Embolism in Hospitalized Patients with Syncope

OBJECTIVES

Approximately one in six patients hospitalized with syncope have pulmonary embolism (PE), according to the PE in Syncope Italian Trial study. Subsequent studies using administrative data have reported a PE prevalence of <3%. The aim of the study was to determine the prevalence and predictors of PE in hospitalized patients with syncope.

METHODS

We retrospectively reviewed the records of patients who were hospitalized in the MedStar Washington Hospital Center between May 1, 2015 and June 30, 2017 with deep venous thrombosis, PE, and syncope. Only patients who presented to the emergency department with syncope were included in the final analysis. PE was diagnosed by either positive computed tomographic angiography or a high-probability ventilation-perfusion scan. Univariate and multivariate logistic regressions were used to assess the associations between clinical variables and the diagnosis of PE in patients with syncope.

RESULTS

Of the 408 patients hospitalized with syncope (mean age, 67.5 years; 51% men [N = 208]), 25 (6%) had a diagnosis of PE. Elevated troponin levels (odds ratio 6.6, 95% confidence interval 1.9-22.9) and a dilated right ventricle on echocardiogram (odds ratio 6.9, 95% confidence interval 2.0-23.6) were independently associated with the diagnosis of PE. Age, active cancer, and history of deep venous thrombosis were not associated with the diagnosis of PE.

CONCLUSIONS

The prevalence of PE in this study is approximately one-third of the reported prevalence in the PE in Syncope Italian Trial study and almost three times the value reported in administrative data-based studies. PE should be suspected in patients with syncope and elevated troponin levels or a dilated right ventricle on echocardiogram.

B-Type Natriuretic Peptides and Cardiac Troponins for Diagnosis and Risk-Stratification of Syncope

BACKGROUND

The utility of BNP (B-type natriuretic peptide), NT-proBNP (N-terminal proBNP), and hs-cTn (high-sensitivity cardiac troponin) concentrations for diagnosis and risk-stratification of syncope is incompletely understood.

METHODS

We evaluated the diagnostic and prognostic accuracy of BNP, NT-proBNP, hs-cTnT, and hs-cTnI concentrations, alone and against those of clinical assessments, in patients >45-years old presenting with syncope to the emergency department in a prospective diagnostic multicenter study. BNP, NT-proBNP, hs-cTnT and hs-cTnI concentrations were measured in a blinded fashion. Cardiac syncope, as adjudicated by 2 physicians based on all information available including cardiac work-up and 1-year follow-up, was the diagnostic end point. EGSYS (Evaluation of Guidelines in Syncope Study), a syncope-specific diagnostic score, served as the diagnostic comparator. Death and major adverse cardiac events at 30 and 720 days were the prognostic end points. Major adverse cardiac events were defined as death, cardiopulmonary resuscitation, life-threatening arrhythmia, implantation of pacemaker/implantable cardioverter defibrillator, acute myocardial infarction, pulmonary embolism, stroke/transient ischemic attack, intracranial bleeding, or valvular surgery. ROSE (Risk Stratification of Syncope in the Emergency Department), OESIL (Osservatorio Epidemiologico della Sincope nel Lazio), SFSR (San Fransisco Syncope Rule), and CSRS (Canadian Syncope Risk Score) served as the prognostic comparators.

RESULTS

Among 1538 patients eligible for diagnostic assessment, cardiac syncope was the adjudicated diagnosis in 234 patients (15.2%). BNP, NT-proBNP, hs-cTnT, and hs-cTnI were significantly higher in cardiac syncope versus other causes (P<0.01). The diagnostic accuracy for cardiac syncope, as quantified by the area under the curve, was 0.77 to 0.78 (95% CI, 0.74-0.81) for all 4 biomarkers, and superior to EGSYS (area under the curve, 0.68 [95%-CI 0.65-0.71], P<0.001). Combining BNP/NT-proBNP with hs-cTnT/hs-cTnI further improved diagnostic accuracy to an area under the curve of 0.81 (P<0.01). BNP, NT-proBNP, hs-cTnT, and hs-cTnI cut-offs, achieving predefined thresholds for sensitivity and specificity (95%), allowed for rule-in or rule-out of ≈30% of all patients. A total of 450 major adverse cardiac events occurred during follow-up. The prognostic accuracy of BNP, NT-proBNP, hs-cTnI, and hs-cTnT for major adverse cardiac events was moderate-to-good (area under the curve, 0.75-0.79), superior to ROSE, OESIL, and SFSR, and inferior to CSRS.

CONCLUSIONS

BNP, NT-proBNP, hs-cTnT, and hs-cTnI concentrations provide useful diagnostic and prognostic information in emergency department patients with syncope.

CLINICAL TRIAL REGISTRATION

URL: https://www.

CLINICALTRIALS

gov. Unique identifier: NCT01548352.

Clinical Benefit of Hospitalization for Older Adults With Unexplained Syncope: A Propensity-Matched Analysis

STUDY OBJECTIVE

Many adults with syncope are hospitalized solely for observation and testing. We seek to determine whether hospitalization versus outpatient management for older adults with unexplained syncope is associated with a reduction in postdisposition serious adverse events at 30 days.

METHODS

We performed a propensity score analysis using data from a prospective, observational study of older adults with unexplained syncope or near syncope who presented to 11 emergency departments (EDs) in the United States. We enrolled adults (≥60 years) who presented with syncope or near syncope. We excluded patients with a serious diagnosis identified in the ED. Clinical and laboratory data were collected on all patients. The primary outcome was rate of post-ED serious adverse events at 30 days.

RESULTS

We enrolled 2,492 older adults with syncope and no serious ED diagnosis from April 2013 to September 2016. Mean age was 73 years (SD 8.9 years), and 51% were women. The incidence of serious adverse events within 30 days after the index visit was 7.4% for hospitalized patients and 3.19% for discharged patients, representing an unadjusted difference of 4.2% (95% confidence interval 2.38% to 6.02%). After propensity score matching on risk of hospitalization, there was no statistically significant difference in serious adverse events at 30 days between the hospitalized group (4.89%) and the discharged group (2.82%) (risk difference 2.07%; 95% confidence interval -0.24% to 4.38%).

CONCLUSION

In our propensity-matched sample of older adults with unexplained syncope, for those with clinical characteristics similar to that of the discharged cohort, hospitalization was not associated with improvement in 30-day serious adverse event rates.

Evaluating patients presenting to the emergency department after syncope: validation of the Canadian Syncope Risk Score

BACKGROUND

Syncope is a common problem but can have any of a broad range of underlying causes. Initial evaluation of the patient in the emergency department often does not identify a specific cause, and the cornerstone of management is reliable risk stratification with clinical decision rules.

OBJECTIVES

The primary objective is to validate the utility and safety of the Canadian Syncope Risk Score (CSRS) as a clinical decision rule when assessing patients who present with syncope to Australian emergency departments. Our secondary objective is to evaluate the economic benefits of diverting patients with syncope at low risk of serious adverse events from admission to hospital.

METHODS AND ANALYSIS

Prospective, observational study. Patients aged 18 years or more who present to the emergency department (ED) after syncope in the preceding 24 hours and have returned to their baseline state will be enrolled. Patients will be contacted by telephone to determine whether they have experienced any adverse events within 30 days of their initial presentation to the ED. The CSRS will be applied retrospectively to determine the relationship between whether patients were admitted to hospital or discharged home and the reporting of serious adverse events for each CSRS risk level. We will also undertake a cost-effectiveness analysis from the health care perspective.

ETHICS APPROVAL

Prince Charles Hospital Human Research Ethics Committee (reference, HREC/17/QPCH/48).

DISSEMINATION OF RESULTS

Outcomes will be disseminated by Queensland Health and the funding body via social media, presented at local and national emergency medicine conferences, and published in international emergency medicine and health economics journals.

CLINICAL TRIALS REGISTRATION

Not applicable.

Effects of loss of consciousness on maxillofacial fractures in simple falls

BACKGROUND/AIMS

Loss of consciousness while falling is reported to increase the risk of more severe injury. However, few studies of maxillofacial injuries have been reported. The aim of this study was to investigate the effects of loss of consciousness on maxillofacial fractures in falls on a level surface (simple falls).

MATERIAL AND METHODS

Patients with maxillofacial fractures caused by simple falls were subdivided into two categories: patients who fell without loss of consciousness and patients who fell with loss of consciousness, according to the Guidelines for the Diagnosis and Management of Syncope (version 2009). The severity of the injuries was compared between these two groups.

RESULTS

In 413 patients with maxillofacial fractures, 58 cases were falls without loss of consciousness, and 44 cases were falls with loss of consciousness. In falls with loss of consciousness, 54.5% were reflex syncope, followed by syncope due to orthostatic hypotension (15.9%), epilepsy (15.9%), and cardiac syncope (9.1%). The average number of fracture lines in the mandible was significantly lower in falls without loss of consciousness (1.53 ± 0.7) than in falls with loss of consciousness (2.00 ± 1.00) (P = 0.045). The average Facial Injury Severity Scale score was lower in falls without loss of consciousness (2.24 ± 1.20) than in falls with loss of consciousness (2.68 ± 1.39). Fractures of other parts of the body were significantly more common in falls without loss of consciousness (22.2%) than in falls with loss of consciousness (9.1%) (P = 0.0135).

CONCLUSIONS

Patients with loss of consciousness and maxillofacial fractures due to simple falls showed a tendency to sustain more severe maxillofacial injuries than those without loss of consciousness.

Analysis of Temporal and Causal Relationship Between Syncope and 30-Day Events in a Cohort of Emergency Department Patients to Identify the True Rate of Short-term Outcomes

BACKGROUND

There are a limited number of studies on the short-term prognosis of syncopal patients, and those available are heterogeneous and often have considered events without a clear relationship with the syncopal episode as serious outcomes.

OBJECTIVE

The aim of this study was to identify the incidence of short-term true outcomes of a syncopal episode, only considering those occurring after a reasonable period of time, with a plausible causal relationship with index syncope as well as syncopal recurrences causing major trauma.

METHODS

In this retrospective, observational study, we assessed all patients managed in the emergency department (ED) during a 6-month period, with 30 days of follow-up.

RESULTS

The study population consisted of 982 consecutive syncopal patients. We observed short-term serious events, in a broad sense, in 154 patients (15.7%), the most frequent being dysrhythmias (20.8%), cerebrovascular accidents (18.2%), major traumatic injuries (16.2%), death (13%), and myocardial infarction (9.7%). Most of these events (63.6%) could be identified within 72 h, mainly in the ED. Only 19 patients (2.2% of the sample), experienced a true short-term outcome (7 deaths, 1 myocardial infarction, 9 dysrhythmias, 1 major bleeding event, and 1 traumatic syncopal recurrence).

CONCLUSIONS

The incidence of short-term true outcomes of syncope is extremely low. Distinguishing true outcomes from other events has a crucial significance for understanding the real prognostic role of syncope and for planning ED management. Once patients with syncope as a direct consequence of an acute disease needing admission by itself are excluded, most patients with unexplained syncope could be safely discharged after primary evaluation and brief ED monitoring.

Review article: Utility of troponin after syncope: A systematic review and meta-analysis

The role of serum troponin testing in patients presenting to the ED after syncope is unclear. The aim of this systematic review was to examine the practice and utility of troponin testing among patients presenting to the ED after syncope. We conducted a search of MEDLINE, Embase, Cochrane Library, Web of Science and Scopus databases from 1990 to February 2017 using keyword and subject headings for syncope and troponin testing. Design and results of the included studies are extracted. Studies were assessed for heterogeneity and the pooled proportion of measured troponin and positive troponin result described. There were nine studies included for analysis. Significant statistical heterogeneity among studies was observed (P < 0.001). Using the random effects model, the pooled proportion of patients presenting to the ED after syncope who had troponin measured was 0.64 (95% CI 0.46-0.82). Among patients who had been troponin tested, the pooled proportion who had a positive result was 0.19 (95% CI 0.13-0.26). Variability among reported outcomes prevented further meta-analysis. Troponin testing was commonly performed for the assessment of patients with syncope with a substantial proportion returning positive results. The correlation between raised troponin and patient outcomes was not adequately reported. It is possible that an elevated troponin may indicate serious illness, rather than myocardial damage alone.

Outcomes in syncope research: a systematic review and critical appraisal

Syncope is the common clinical manifestation of different diseases, and this makes it difficult to define what outcomes should be considered in prognostic studies. The aim of this study is to critically analyze the outcomes considered in syncope studies through systematic review and expert consensus. We performed a systematic review of the literature to identify prospective studies enrolling consecutive patients presenting to the Emergency Department with syncope, with data on the characteristics and incidence of short-term outcomes. Then, the strengths and weaknesses of each outcome were discussed by international syncope experts to provide practical advice to improve future selection and assessment. 31 studies met our inclusion criteria. There is a high heterogeneity in both outcome choice and incidence between the included studies. The most commonly considered 7-day outcomes are mortality, dysrhythmias, myocardial infarction, stroke, and rehospitalisation. The most commonly considered 30-day outcomes are mortality, haemorrhage requiring blood transfusion, dysrhythmias, myocardial infarction, pacemaker or implantable defibrillator implantation, stroke, pulmonary embolism, and syncope relapse. We present a critical analysis of the pros and cons of the commonly considered outcomes, and provide possible solutions to improve their choice in ED syncope studies. We also support global initiatives to promote the standardization of patient management and data collection.

Application of outpatient cardiac testing among emergency department patients with syncope

OBJECTIVES

2.6% of ED syncope patients will suffer cardiac serious adverse events (SAEs) within 30 days of disposition, and outpatient cardiac testing can improve patient safety. The objective is to determine whether outpatient cardiac testing for ED syncope patients is being appropriately ordered after discharge. To this end, we describe the proportion of high-risk and non-high (low and medium)-risk ED syncope patients as per the Canadian Syncope Risk Score (CSRS) who have a SAE after ED discharge, and the proportion referred for outpatient cardiac testing.

METHODS

Our multicentre prospective cohort study enrolled adult syncope patients between 2010 and 2014 in five academic EDs. We collected patient characteristics, disposition, CSRS predictors, outpatient referrals and testing results (Holter, echocardiography), and 30-day adjudicated SAE (death due to unknown/cardiac cause, myocardial infarction, arrhythmia and structural heart disease). We used descriptive statistics (mean, SD) to report our results.

RESULTS

Of 3584 enrolled patients (mean age 50.9 years, 57.7% women), 800 patients (22.3%) received an outpatient referral. Of these 800 patients, 40.3% of the non-high-risk patients (305/756) and 54.5% of the high-risk patients (24/44) received outpatient cardiac testing. Of all patients who received cardiac testing, five (1.5%; 95% CI 0.6% to 3.5%) suffered outpatient SAE (60.0% arrhythmias). Of all patients who did not receive cardiac testing, four patients (0.9%; 95% CI 0.3% to 2.2%) suffered SAE (all arrhythmias). Of the 20 (45.5%) high-risk patients who did not receive testing, two patients (10.0%; 95% CI 2.8% to 30.1%) suffered arrhythmias outside the hospital, while among the 451 (59.7%) non-high-risk patients, only two (0.4%; 95% CI 0.1% to 1.6%) suffered outpatient arrhythmias.

CONCLUSION

Outpatient cardiac testing is largely underused, especially among high-risk ED syncope patients. Better guidelines for outpatient cardiac testing are needed, as the practice is highly variable and mismatched with patient risk.

Development of a Patient Decision Aid for Syncope in the Emergency Department: the SynDA Tool

OBJECTIVES

The objective was to develop a patient decision aid (DA) to promote shared decision making (SDM) for stable, alert patients who present to the emergency department (ED) with syncope.

METHODS

Using input from patients, clinicians, and experts in the field of syncope, health care design, and SDM, we created a prototype of a paper-based DA to engage patients in the disposition decision (admission vs. discharge) after an unremarkable ED evaluation for syncope. In phase 1, we conducted one-on-one semistructured exploratory interviews with 10 emergency physicians and 10 ED syncope patients. In phase 2, we conducted one-on-one directed interviews with 15 emergency care clinicians, five cardiologists, and 12 ED syncope patients to get detailed feedback on DA content and design. We iteratively modified the aid using feedback from each interviewee until clarity and usability had been optimized.

RESULTS

The 11 × 17-inch, paper-based DA, titled SynDA, includes four sections: 1) explanation of syncope, 2) explanation of future risks, 3) personalized 30-day risk estimate, and 4) disposition options. The personalized risk estimate is calculated using a recently published syncope risk-stratification tool. This risk estimate is stated in natural frequency and graphically displayed using a 100-person color-coded pictogram. Patient-oriented questions are included to stimulate dialogue between patient and clinician. At the end of the development process, patient and physician participants expressed satisfaction with the clarity and usability of the DA.

CONCLUSIONS

We iteratively developed an evidence-based DA to facilitate SDM for alert syncope patients after an unremarkable ED evaluation. Further testing is required to determine its effects on patient care. This DA has the potential to improve care for syncope patients and promote patient-centered care in emergency medicine.

Predictors of Short-Term Outcomes after Syncope: A Systematic Review and Meta-Analysis

Introduction

We performed a systematic review and meta-analysis to identify predictors of serious clinical outcomes after an acute-care evaluation for syncope.

Methods

We identified studies that assessed for predictors of short-term (≤30 days) serious clinical events after an emergency department (ED) visit for syncope. We performed a MEDLINE search (January 1, 1990 – July 1, 2017) and reviewed reference lists of retrieved articles. The primary outcome was the occurrence of a serious clinical event (composite of mortality, arrhythmia, ischemic or structural heart disease, major bleed, or neurovascular event) within 30 days. We estimated the sensitivity, specificity, and likelihood ratio of findings for the primary outcome. We created summary estimates of association on a variable-by-variable basis using a Bayesian random-effects model.

Results

We reviewed 2,773 unique articles; 17 met inclusion criteria. The clinical findings most predictive of a short-term, serious event were the following: 1) An elevated blood urea nitrogen level (positive likelihood ratio [LR+]: 2.86, 95% confidence interval [CI] [1.15, 5.42]); 2); history of congestive heart failure (LR+: 2.65, 95%CI [1.69, 3.91]); 3) initial low blood pressure in the ED (LR+: 2.62, 95%CI [1.12, 4.9]); 4) history of arrhythmia (LR+: 2.32, 95%CI [1.31, 3.62]); and 5) an abnormal troponin value (LR+: 2.49, 95%CI [1.36, 4.1]). Younger age was associated with lower risk (LR−: 0.44, 95%CI [0.25, 0.68]). An abnormal electrocardiogram was mildly predictive of increased risk (LR+ 1.79, 95%CI [1.14, 2.63]).

Conclusion

We identified specific risk factors that may aid clinical judgment and that should be considered in the development of future risk-prediction tools for serious clinical events after an ED visit for syncope.

Prevalence of Pulmonary Embolism in Patients With Syncope

IMPORTANCE

Sparse data and conflicting evidence exist on the prevalence of pulmonary embolism (PE) in patients with syncope.

OBJECTIVE

To estimate the prevalence of PE among patients presenting to the emergency department (ED) for evaluation of syncope.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective, observational study analyzed longitudinal administrative data from 5 databases in 4 different countries (Canada, Denmark, Italy, and the United States). Data from all adult patients (aged ≥18 years) who presented to the ED were screened to identify those with syncope codes at discharge. Data were collected from January 1, 2000, through September 30, 2016.

MAIN OUTCOMES AND MEASURES

The prevalence of PE at ED and hospital discharge, identified using codes from the International Classification of Diseases, was considered the primary outcome. Two sensitivity analyses considering prevalence of PE at 90 days of follow-up and prevalence of venous thromboembolism were performed.

RESULTS

A total of 1 671 944 unselected adults who presented to the ED for syncope were included. The prevalence of PE, according to administrative data, ranged from 0.06% (95% CI, 0.05%-0.06%) to 0.55% (95% CI, 0.50%-0.61%) for all patients and from 0.15% (95% CI, 0.14%-0.16%) to 2.10% (95% CI, 1.84%-2.39%) for hospitalized patients. The prevalence of PE at 90 days of follow-up ranged from 0.14% (95% CI, 0.13%-0.14%) to 0.83% (95% CI, 0.80%-0.86%) for all patients and from 0.35% (95% CI, 0.34%-0.37%) to 2.63% (95% CI, 2.34%-2.95%) for hospitalized patients. Finally, the prevalence of venous thromboembolism at 90 days ranged from 0.30% (95% CI, 0.29%-0.31%) to 1.37% (95% CI, 1.33%-1.41%) for all patients and from 0.75% (95% CI, 0.73%-0.78%) to 3.86% (95% CI, 3.51%-4.24%) for hospitalized patients.

CONCLUSIONS AND RELEVANCE

Pulmonary embolism was rarely identified in patients with syncope. Although PE should be considered in every patient, not all patients should undergo evaluation for PE.

Structural heart disease as the cause of syncope

We described the clinical evolution of patients with structural heart disease presenting at the emergency room with syncope. Patients were stratified according to their syncope etiology and available scores for syncope prognostication. Cox proportional hazard models were used to investigate the relationship between etiology of the syncope and event-free survival. Of the 82,678 emergency visits during the study period, 160 (0.16%) patients were there due to syncope, having a previous diagnosis of structural heart disease. During the median follow-up of 33.8±13.8 months, mean age at the qualifying syncope event was 68.3 years and 40.6% of patients were male. Syncope was vasovagal in 32%, cardiogenic in 57%, orthostatic hypotension in 6%, and of unknown causes in 5% of patients. The primary composite endpoint death, readmission, and emergency visit in 30 days was 39.4% in vasovagal syncope and 60.6% cardiogenic syncope (P<0.001). Primary endpoint-free survival was lower for patients with cardiogenic syncope (HR=2.97, 95%CI=1.94-4.55; P<0.001). The scores were analyzed for diagnostic performance with area under the curve (AUC) and did not help differentiate patients with an increased risk of adverse events. The differential diagnosis of syncope causes in patients with structural heart disease is important, because vasovagal and postural hypotension have better survival and less probability of emergency room or hospital readmission. The available scores are not reliable tools for prognosis in this specific patient population.

A Population-Based Study of Syncope in the Young

BACKGROUND

The prevalence, hospitalization patterns, and outcomes of pediatric and adolescent syncope have not been rigorously characterized.

METHODS

Patients < 20 years presenting to an emergency department (ED) with a primary diagnosis of syncope (International Classification of Diseases, 10th revision, code R55) between fiscal year (FY) 2006/2007 and FY 2013/2014 in the province of Alberta, Canada were grouped according to discharge status from the ED, ie, (1) admitted to hospital and (2) discharged without admission. Temporal trends and differences in baseline characteristics, medication use, and outcomes between admitted and discharged patients were examined.

RESULTS

The prevalence of syncope increased from 143/100,000 population in FY 2006/2007 to 166/100,000 population in FY 2013/2014 (P < 0.01). The majority of the 11,488 patients who presented to the ED with syncope were discharged home (n = 11,214 [98%]). Cardiac disease was present in 12.7% and thoracic conditions were present in 8% of the study population. A majority of patients (66.2% admitted and 56.4% discharged; P = 0.018) were taking a prescription drug in the year before presentation. By 30 days, 26.1% of admitted patients had a second ED presentation and 8.1% had a rehospitalization. Among discharged patients, the 30-day repeated ED presentation rate was 11.7% and the hospitalization rate was 1.1%. By 1 year, the rates of repeated ED visits increased to 64.1% and 47.5%, and rehospitalization rates increased to 21.4% and 6.8% among admitted and discharged patients, respectively.

CONCLUSIONS

Our data suggest that pediatric and adolescent syncope is increasing in prevalence and represents a growing public health problem. This population has a high burden of comorbidities that likely contribute to increased health care resource use and polypharmacy.

Shared Decision-Making as the Future of Emergency Cardiology

Shared decision-making is playing an increasingly large role in emergency cardiovascular care. Although there are many challenges to successfully performing shared decision-making in the emergency department, there are numerous clinical scenarios in which it should be used. In this article, we explore new research and emerging decision aids in the following emergency care scenarios: (1) low-risk chest pain; (2) new-onset atrial fibrillation; and (3) moderate-risk syncope. These decision aids are designed to engage patients and facilitate shared decision-making for specific treatment and disposition (admit vs discharge) decisions. We then offer a 3-step, practical approach to performing shared decision-making in the acute care setting, on the basis of broad stakeholder input and previous conceptual work. Step 1 involves simply acknowledging that a clinical decision needs to be made. Step 2 involves a shared discussion about the working diagnosis and the options for care in the context of the patient's values, preferences, and circumstances. The third and final step requires the patient and provider to agree on a plan of action regarding further medical care. The implementation of shared decision-making in emergency cardiology has the potential to shift the paradigm of clinical practice from paternalism toward mutualism and improve the quality and experience of care for our patients.

Syncope and the risk of sudden cardiac death: Evaluation, management, and prevention

Syncope is a clinical syndrome defined as a relatively brief self-limited transient loss of consciousness (TLOC) caused by a period of inadequate cerebral nutrient flow. Most often the trigger is an abrupt drop of systemic blood pressure. True syncope must be distinguished from other common non-syncope conditions in which real or apparent TLOC may occur such as seizures, concussions, or accidental falls. The causes of syncope are diverse, but in most instances, are relatively benign (e.g., reflex and orthostatic faints) with the main risks being accidents and/or injury. However, in some instances, syncope may be due to more worrisome conditions (particularly those associated with cardiac structural disease or channelopathies); in such circumstances, syncope may be an indicator of increased morbidity and mortality risk, including sudden cardiac death (SCD). Establishing an accurate basis for the etiology of syncope is crucial in order to initiate effective therapy. In this review, we focus primarily on the causes of syncope that are associated with increased SCD risk (i.e., sudden arrhythmic cardiac death), and the management of these patients. In addition, we discuss the limitations of our understanding of SCD in relation to syncope, and propose future studies that may ultimately address how to improve outcomes of syncope patients and reduce SCD risk.

Predicting Short-term Risk of Arrhythmia among Patients With Syncope: The Canadian Syncope Arrhythmia Risk Score

BACKGROUND

Syncope can be caused by serious occult arrhythmias not evident during initial emergency department (ED) evaluation. We sought to develop a risk tool for predicting 30-day arrhythmia or death after ED disposition.

METHODS

We conducted a multicenter prospective cohort study at six tertiary care EDs and included adults (≥16 years) with syncope. We collected standardized variables from clinical evaluation and investigations including electrocardiogram and troponin at index presentation. Adjudicated outcomes included death or arrhythmias including procedural interventions for arrhythmia within 30 days. We used multivariable logistic regression to derive the prediction model and bootstrapping for interval validation to estimate shrinkage and optimism.

RESULTS

A total of 5,010 patients (mean ± SD age = 53.4 ± 23.0 years, 54.8% females, and 9.5% hospitalized) were enrolled with 106 (2.1%) patients suffering 30-day arrhythmia/death after ED disposition. We examined 39 variables and eight were included in the final model: lack of vasovagal predisposition, heart disease, any ED systolic blood pressure < 90 or > 180 mm Hg, troponin (>99th percentile), QRS duration > 130 msec, QTc interval > 480 msec, and ED diagnosis of cardiac/vasovagal syncope (optimism corrected C-statistic 0.90 [95% CI = 0.87-0.93]; Hosmer-Lemeshow p = 0.08). The Canadian Syncope Arrhythmia Risk Score had a risk ranging from 0.2% to 74.5% for scores of -2 to 8. At a threshold score of ≥0, the sensitivity was 97.1% (95% CI = 91.6%-99.4%) and specificity was 53.4% (95% CI = 52.0%-54.9%).

CONCLUSIONS

The Canadian Syncope Arrhythmia Risk Score can improve patient safety by identification of those at risk for arrhythmias and aid in acute management decisions. Once validated, the score can identify low-risk patients who will require no further investigations.

Cardiovascular Conditions in the Observation Unit: Beyond Chest Pain

The first emergency department observation units (EDOUs) focused on chest pain and potential acute coronary syndromes. However, most EDOUs now cover multiple other conditions that lend themselves to protocolized, aggressive diagnostic and therapeutic regimens. In this article, the authors discuss the management of 4 cardiovascular conditions that have been successfully deployed in EDOUs around the country.