Duration of Electrocardiographic Monitoring of Emergency Department Patients With Syncope.

BACKGROUND: The optimal duration of cardiac rhythm monitoring after emergency department (ED) presentation for syncope is poorly described. We sought to describe the incidence and time to arrhythmia occurrence to inform decisions regarding duration of monitoring based on ED risk stratification. METHODS: We conducted a prospective cohort study with enrolled adult patients (≥16 years old) presenting within 24 hours of syncope at 6 EDs. We collected baseline characteristics, time of syncope and ED arrival, and the Canadian Syncope Risk Score (CSRS) risk category. We followed subjects for 30 days, and our adjudicated primary outcome was serious arrhythmic conditions (arrhythmias, interventions for arrhythmias, and unexplained death). After excluding patients with an obvious serious condition on ED presentation and those with missing CSRS predictors, we used Kaplan-Meier analysis to describe the time to serious arrhythmic outcomes. RESULTS: A total of 5581 patients (mean age, 53.4 years; 54.5% females; 11.6% hospitalized) were available for analysis, including 346 (6.2%) for whom the 30-day follow-up was incomplete and who were censored at the last follow-up time. A total of 417 patients (7.5%) experienced serious outcomes, 207 of which (3.7%; 95% CI, 3.3%-4.2%) were arrhythmic (161 arrhythmias, 30 cardiac device implantations, 16 unexplained deaths). Overall, 4123 (73.9%) were classified as CSRS low risk, 1062 (19.0%) medium risk, and 396 (7.1%) high risk. The CSRS accurately stratified subjects as low risk (0.4% risk for 30-day arrhythmic outcome), medium risk (8.7% risk), and high risk (25.3% risk). One-half of arrhythmic outcomes were identified within 2 hours of ED arrival in low-risk patients and within 6 hours in medium- and high-risk patients, and the residual risk after these cut points were 0.2% for low-risk, 5.0% for medium-risk, and 18.1% for high-risk patients. Overall, 91.7% of arrhythmic outcomes among medium- and high-risk patients, including all ventricular arrhythmias, were identified within 15 days. None of the low-risk patients experienced ventricular arrhythmia or unexplained death, whereas 0.9% of medium-risk patients and 6.3% of high-risk patients experienced them ( P<0.0001). CONCLUSIONS: Serious underlying arrhythmia was often identified within the first 2 hours of ED arrival for CSRS low-risk patients and within 6 hours for CSRS medium- and high-risk patients. Outpatient cardiac rhythm monitoring for 15 days for selected medium-risk patients and all high-risk patients discharged from the hospital should also be considered.

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.

Outcomes and emergency medical services resource utilization among patients with syncope arriving to the emergency department by ambulance.

OBJECTIVE: Syncope accounts for 1% of emergency department (ED) visits, yet few experience a serious adverse event (SAE). Two-thirds of syncope patients are transported to the ED by ambulance, placing considerable burden on emergency medical services (EMS), and many of these transports may be unnecessary. We estimated the proportion of syncope patients who fell into a low-risk category based on an ED diagnosis of vasovagal syncope and the absence of EMS intervention, hospitalization, or SAE. METHODS: We conducted a multicentre prospective cohort study enrolling adult syncope patients transported to the ED by ambulance over 13 months. We collected demographics and EMS interventions, and followed patients for 30 days to identify all SAE, including death, dysrhythmia, myocardial infarction, aortic dissection, pulmonary embolism, subarachnoid hemorrhage, significant hemorrhage, and related procedural interventions. RESULTS: Of 990 (67.2%) patients transported to the ED by ambulance, 121 had EMS interventions, 137 suffered 30-day SAE, 393 (39.7%; 95%CI 36.6, 42.8) were deemed low risk, 41 patients with vasovagal syncope were lost to follow-up, and 298 patients were diagnosed with non-vasovagal syncope. During transport, 121 (12.2%; 95%CI 10.2, 14.3) patients underwent some EMS intervention, and 137 (14.6%; 95%CI 12.4, 16.9) suffered SAEs within 30 days. CONCLUSION: About 40% of patients transported to the ED by ambulance are at low risk and may not benefit from paramedic care or transport to a hospital. A robust clinical decision tool would help identify patients safe for treat-and-release, diversion to alternative care, or rapid offload into low-acuity ED areas, potentially reducing EMS workload and cost.

OBJECTIF: Les syncopes motivent 1 % des consultations au service des urgences (SU), mais le malaise entraîne peu d'événements indésirables graves (EIG). Ainsi, deux tiers des patients ayant subi une syncope sont transportés en ambulance au SU, ce qui impose un lourd fardeau sur les services médicaux d'urgence (SMU), et pourtant bon nombre de transports effectués seraient non nécessaires. Aussi l'étude visait-elle à estimer la proportion de patients ayant subi une syncope dont l'état serait jugé à faible risque d'après le diagnostic de syncope vasovagale posé au SU ainsi que d'après l'absence d'intervention faite par les SMU, d'hospitalisation ou d'EIG. MÉTHODE: Il s'agit d'une étude prospective de cohortes, multicentrique, menée chez des adultes qui ont subi une syncope et qui ont été transportés en ambulance au SU, sur une période de 13 mois. Ont été recueillies des données démographiques ainsi que les notes sur les interventions effectuées par les SMU; à cela s'ajoute un suivi de 30 jours aux fins de collecte de renseignements sur tout EIG : mort, arythmie, infarctus du myocarde, dissection de l'aorte, embolie pulmonaire, hémorragie sous-arachnoïdienne, hémorragie importante et gestes interventionnels liés aux troubles en question. RÉSULTATS: Au total, 990 patients (67,2 %) ont été transportés en ambulance au SU; sur ce nombre, 121 ont subi des interventions pratiquées par les SMU; 137 ont connu un EIG au cours des 30 jours suivant le malaise; 393 (39,7 %; IC à 95 % : 36,6-42,8) ont été jugés à faible risque; 41 ayant fait une syncope vasovagale ont été perdus de vue durant le suivi; et 298, ont fait une syncope non vasovagale. Durant le transport, 121 patients (12,2 %; IC à 95 % : 10,2-14,3) ont subi une forme quelconque d'intervention par les SMU et, au cours des 30 jours de suivi, 137 (14,6 %; IC à 95 % : 12,4-16,9) ont connu un EIG. CONCLUSION: Environ 40 % des patients transportés en ambulance au SU connaissent un faible risque et, dans leur cas, la prestation de soins paramédicaux ou le transport à l'hôpital pourraient ne pas être nécessaires. Un outil d'aide à la décision clinique qui soit digne de confiance pourrait faciliter le repérage des patients dont l'état se prêterait au traitement suivi du congé, à une orientation vers d'autres types de soins ou à un passage rapide dans des zones de petites urgences, ce qui permettrait à la fois de réduire la charge de travail des SMU ainsi que les coûts.

Syncope Prognosis Based on Emergency Department Diagnosis: A Prospective Cohort Study.

OBJECTIVE: Relatively little is known about outcomes after disposition among syncope patients assigned various diagnostic categories during emergency department (ED) evaluation. We sought to measure the outcomes among these groups within 30 days of the initial ED visit. METHODS: We prospectively enrolled adult syncope patients at six EDs and excluded patients with presyncope, persistent mental status changes, intoxication, seizure, and major trauma. Patient characteristics, ED management, diagnostic impression (presumed vasovagal, orthostatic, cardiac, or other/unknown) at the end of the ED visit, and physicians' confidence in assigning the etiology were collected. Serious outcomes at 30 days included death, arrhythmia, myocardial infarction, structural heart disease, pulmonary embolism, and hemorrhage. RESULTS: A total of 5,010 patients (mean ± SD age = 53.4 ± 23.0 years; 54.8% females) were enrolled; 3.5% suffered serious outcomes-deaths (0.3%), arrhythmias (1.8%), nonarrhythmic cardiac (0.5%), and noncardiac (0.9%) including pulmonary embolism (0.2%). The cause of syncope was presumed as vasovagal among 53.3% and cardiac in 5.4% of patients. The proportion of patients with ED investigations (p < 0.001) and short-term serious outcomes (p < 0.01) increased in each diagnostic category in the following order: presumed vasovagal, orthostatic hypotension, other/unknown cause, and cardiac. No deaths occurred in patients with presumed vasovagal syncope. A higher proportion of all serious outcomes occurred among patients suspected of cardiac syncope in the ED (p < 0.01). Confidence was highest among physicians for a presumed vasovagal syncope diagnosis and lowest when the cause was other/unknown. CONCLUSION: Short-term serious outcomes strongly correlated with the etiology assigned in the ED visit. The importance of the physician's clinical judgment should be further studied to determine if it should become incorporated in risk-stratification tools for prognostication and safe management of ED syncope patients.

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.

Reasons for Hospitalization Among Emergency Department Patients With Syncope.

BACKGROUND: Variations in syncope management exist. Our objective was to identify the reasons for consultations and hospitalizations and outcomes among emergency department (ED) syncope patients. METHODS: We conducted a prospective cohort study to enroll adult syncope patients at five EDs. We collected baseline characteristics, reasons for consultation and hospitalization, and hospital length of stay. Adjudicated 30-day serious adverse events (SAEs) including death, myocardial infarction, arrhythmia, structural heart disease, pulmonary embolism, significant hemorrhage, and procedural intervention. We used descriptive analysis. RESULTS: From 4,064 enrolled patients (mean ± SD age = 53.1 ± 23.2 years; 55.9% female), 3,255 (80.1%) were discharged directly by the ED physician. Of those with no SAEs identified in the ED (n = 600), 42.8% of referrals and 46.5% of hospitalizations were for suspected arrhythmias, and 71.2% of patients hospitalized for arrhythmias had no cause identified. SAEs among groups were 9.7% in total, 2.5% discharged by ED physician, 3.4% discharged by consultant, 21.7% as inpatient, and 4.8% following discharge from hospital. The median hospital length of stay for suspected arrhythmias was 5 days (interquartile range = 3 to 8 days). CONCLUSION: Cardiac syncope, particularly suspected arrhythmia, was the major reason for ED referrals and hospitalization. The majority of patients hospitalized for cardiac monitoring had no identified cause. An important number of patients suffered SAEs, particularly arrhythmias, outside the hospital. Development of a risk-stratification tool and out-of-hospital cardiac monitoring strategy should improve patient safety and save substantial resources.