Frank X. Scheuermeyer

Safety and Efficiency of a Chest Pain Diagnostic Algorithm With Selective Outpatient Stress Testing for Emergency Department Patients With Potential Ischemic Chest Pain

STUDY OBJECTIVE Chest pain units have been used to monitor and investigate emergency department (ED) patients with potential ischemic chest pain to reduce the possibility of missed acute coronary syndrome. We seek to optimize the use of hospital resources by implementing a chest pain diagnostic algorithm. METHODS This was a prospective cohort study of ED patients with potential ischemic chest pain. High-risk patients were referred to cardiology, and patients without ECG or biomarker evidence of ischemia were discharged home after 2 to 6 hours of observation. Emergency physicians scheduled discharged patients for outpatient stress ECGs or radionuclide scans at the hospital within 48 hours. Patients with positive provocative test results were immediately referred back to the ED. The primary outcome was the rate of missed diagnosis of acute coronary syndrome at 30 days. RESULTS We prospectively followed 1,116 consecutive patients who went through the chest pain diagnostic algorithm, of whom 197 (17.7%) were admitted at the index visit and 254 (22.8%) received outpatient testing on discharge. The 30-day acute coronary syndrome event rate was 10.8%, and the 30-day missed acute coronary syndrome rate was 0% (95% confidence interval 0% to 2.4%). Of the 120 acute coronary syndrome cases, 99 (82.5%) were diagnosed at the index ED visit, and 21 patients (17.5%) received the diagnosis during outpatient stress testing. CONCLUSION In ED patients with chest pain, a structured diagnostic approach with time-focused ED decision points, brief observation, and selective application of early outpatient provocative testing appears both safe and diagnostically efficient, even though some patients with acute coronary syndrome may be discharged for outpatient stress testing on the index ED visit.

Thirty-day Outcomes of Emergency Department Patients Undergoing Electrical Cardioversion for Atrial Fibrillation or Flutter

OBJECTIVES While the short-term (<7-day) safety and efficiency of electrical cardioversion for emergency department (ED) patients with atrial fibrillation or flutter have been established, the 30-day outcomes with respect to stroke, thromboembolic events, or death have not been investigated. METHODS A two-center cohort of consecutive ED patients undergoing cardioversion for atrial fibrillation or flutter between January 1, 2000, and September 30, 2007, was retrospectively investigated. This cohort was probabilistically linked with both a regional ED database and the provincial health registry to determine which patients had a subsequent ED visit or hospital admission, stroke, or thromboembolic event or died within 30 days. In addition, trained reviewers performed a detailed chart abstraction on 150 randomly selected patients, with emphasis on demographics, vital signs, medical treatment, and predefined adverse events. Hemodynamically unstable patients or those whose condition was the result of an underlying acute medical diagnosis were excluded. Data were analyzed by descriptive methods. RESULTS During the study period, 1,233 patients made 1,820 visits for atrial fibrillation or flutter to the ED. Of the 400 eligible patients undergoing direct-current cardioversion (DCCV), no patients died, had a stroke, or had a thromboembolic event in the following 30 days (95% confidence interval [CI] = 0.0 to 0.8% for all outcomes). A total of 141 patients were included in the formal chart review, with five patients (3.5%, 95% CI = 0.5% to 6.6%) failing cardioversion, six patients (4.3%, 95% CI = 0.9% to 7.6%) having a minor adverse event that did not change disposition, and five patients (3.5%, 95% CI = 0.5% to 6.6%) admitted to hospital at the index visit. CONCLUSIONS Cardioversion of patients with atrial fibrillation or flutter in the ED appears to have a very low rate of long-term complications.

Comparing the prognosis of those with initial shockable and non-shockable rhythms with increasing durations of CPR: Informing minimum durations of resuscitation

AIM There is little data to inform the appropriate duration of resuscitation attempts for out-of-hospital cardiac arrest (OHCA). We assessed the relationship of elapsed duration since commencement of resuscitation and outcomes, highlighting differences between initial shockable and non-shockable rhythms. METHODS We examined consecutive adult non-traumatic EMS-treated OHCA in a single health region. We plotted the time-dependent accrual of patients with ROSC, as well as dynamic estimates of outcomes as a function of duration from commencement of professional resuscitation, and compared subgroups dichotomized by initial rhythm. Logistic regression tested the association between time-to-ROSC and outcomes. RESULTS Of 1627 adult EMS-treated cases of OHCA, 1617 patients were included; 14% survivors and 10% with favorable neurological outcomes. Time-to-ROSC (per minute increase) was independently associated with survival in those with initial shockable (aOR 0.95, 95% CI 0.92-0.97) and non-shockable (aOR 0.83; 95% CI 0.78-0.88) rhythms. Similar associations were seen with favorable neurologic outcome. The elapsed duration at which the probability of survival fell below 1% was 48 and 15 min in the shockable and non-shockable groups, respectively. Median time-to-termination of resuscitation was 36 and 26 min in the shockable and non-shockable groups, respectively. CONCLUSION The subgroup of initial shockable rhythms showed a less pronounced association of time-to-ROSC with outcomes, and demonstrated higher resilience for neurologically intact survival after prolonged periods of resuscitation. This data can guide minimum durations of resuscitation, however should not be considered as evidence for termination of resuscitation as survival in this cohort may have been improved with longer resuscitation attempts.

Relationship between Time-to-ROSC and Survival in Out-of-hospital Cardiac Arrest ECPR Candidates: When is the Best Time to Consider Transport to Hospital?

Abstract Objective: Extracorporeal cardiopulmonary resuscitation (ECPR) may improve outcomes for refractory out-of-hospital cardiac arrest (OHCA). Transport of intra-arrest patients to hospital however, may decrease CPR quality, potentially reducing survival for those who would have achieved return-of-spontaneous-circulation (ROSC) with further on-scene resuscitation. We examined time-to-ROSC and patient outcomes for the optimal time to consider transport. Methods: From a prospective registry of consecutive adult non-traumatic OHCAs, we identified a hypothetical ECPR-eligible cohort of EMS-treated patients with age ≤ 65, witnessed arrest, and bystander CPR or EMS arrival < 10 minutes. We assessed the relationship between time-to-ROSC and survival, and constructed a ROC curve to illustrate the ability of a pulseless state to predict non-survival with conventional resuscitation. Results: Of 6,571 EMS-treated cases, 1,206 were included with 27% surviving. Increasing time–to–ROSC (per minute) was negatively associated with survival (adjusted OR 0.91; 95%CI 0.89–0.93%). The yield of survivors per minute of resuscitation increased from commencement and started to decline in the 8th minute. Fifty percent and 90% of survivors had achieved ROSC by 8.0 and 24 min, respectively, at which times the probability of survival for those with initial shockable rhythms was 31% and 10%, and for non-shockable rhythms was 5.2% and 1.6%. The ROC curve illustrated that the 16th minute of resuscitation maximized sensitivity and specificity (AUC = 0.87, 95% CI 0.85–0.89). Conclusion: Transport for ECPR should be considered between 8 to 24 minutes of professional on-scene resuscitation, with 16 minutes balancing the risks and benefits of early and later transport. Earlier transport within this window may be preferred if high quality CPR can be maintained during transport and for those with initial non-shockable rhythms.

Thirty-Day and 1-Year Outcomes of Emergency Department Patients With Atrial Fibrillation and No Acute Underlying Medical Cause

STUDY OBJECTIVE Atrial fibrillation is the most common dysrhythmia observed in the emergency department (ED), yet there is little research describing long-term outcomes after ED management. Our objective is to describe ED treatment approach, conversion success rates, ED adverse events, and 30-day and 1-year outcomes for a cohort of ED patients with atrial fibrillation and no acute underlying medical cause. METHODS This retrospective cohort study used a database from 2 urban EDs to identify consecutive patients with an ED discharge diagnosis of atrial fibrillation from April 1, 2006, to March 31, 2010. Comorbidities, rhythms, management, and immediate outcomes were obtained by manual chart review, and patients with an acute underlying medical condition were excluded by predefined criteria. Patients were stratified into 5 groups according to ED management: electrocardioversion, chemical cardioversion, spontaneous cardioversion, rate control only, and no arrhythmia-specific treatment. To identify deaths, strokes, and ED revisits within 1 year, each patients unique provincial health number was linked to the provincial vital statistics registry and the regional ED database. Primary outcome was the number of patients having either stroke or death of any cause at 30 days, stratified by treatment group. RESULTS Of 927 consecutive eligible patients, 121 (13.1%) converted to sinus rhythm before ED intervention, 357 (38.5%) received ED rhythm control, and 449 (48.4%) did not receive rhythm control. Overall, 142 of 927 patients (15.3%) were admitted to the hospital at the index ED visit. At 30 days, 2 patients had a stroke and 5 died (combined outcome rate 0.8%; 95% confidence interval 0.3% to 1.6%). All 7 of these patients were admitted at the index ED visit. CONCLUSION In this large cohort of ED patients with atrial fibrillation and no acute underlying medical cause, the 30-day rate for stroke or death was less than 1%. Nearly 85% of patients-regardless of treatment approach or conversion to sinus rhythm-were discharged at the index ED visit, and none of these patients had a stroke or died at 30 days.

Development and validation of a prediction rule for early discharge of low-risk emergency department patients with potential ischemic chest pain.

OBJECTIVES Current guidelines emphasize that emergency department (ED) patients at low risk for potential ischemic chest pain cannot be discharged without extensive investigations or hospitalization to minimize the risk of missing acute coronary syndrome (ACS). We sought to derive and validate a prediction rule that permitted 20 to 30% of ED patients without ACS safely to be discharged within 2 hours without further provocative cardiac testing. METHODS This prospective cohort study enrolled 1,669 chest pain patients in two blocks in 2000-2003 (development cohort) and 2006 (validation cohort). The primary outcome was 30-day ACS diagnosis. A recursive partitioning model incorporated reliable and predictive cardiac risk factors, pain characteristics, electrocardiographic findings, and cardiac biomarker results. RESULTS In the derivation cohort, 165 of 763 patients (21.6%) had a 30-day ACS diagnosis. The derived prediction rule was 100.0% sensitive and 18.6% specific. In the validation cohort, 119 of 906 patients (13.1%) had ACS, and the prediction rule was 99.2% sensitive (95% CI 95.4-100.0) and 23.4% specific (95% CI 20.6-26.5). Patients have a very low ACS risk if arrival and 2-hour troponin levels are normal, the initial electrocardiogram is nonischemic, there is no history of ACS or nitrate use, age is < 50 years, and defined pain characteristics are met. The validation of the rule was limited by the lack of consistency in data capture, incomplete follow-up, and lack of evaluation of the accuracy, comfort, and clinical sensibility of this clinical decision rule. CONCLUSION The Vancouver Chest Pain Rule may identify a cohort of ED chest pain patients who can be safely discharged within 2 hours without provocative cardiac testing. Further validation across other centres with consistent application and comprehensive and uniform follow-up of all eligible and enrolled patients, in addition to measuring and reporting the accuracy of and comfort level with applying the rule and the clinical sensibility, should be completed prior to adoption and implementation.

Missed Opportunities for Appropriate Anticoagulation Among Emergency Department Patients With Uncomplicated Atrial Fibrillation or Flutter

STUDY OBJECTIVE Emergency department (ED) patients with atrial fibrillation or flutter are at risk of stroke, and guidelines recommend anticoagulation for patients with increased cardiovascular risk. Emergency physicians have a unique opportunity to provide appropriate anticoagulation for such patients, and we wished to investigate whether this was accomplished. METHODS This retrospective cohort study used a database from 2 urban EDs to identify consecutive patients with an ED discharge diagnosis of atrial fibrillation or flutter from April 1, 2006, to March 31, 2010, who were managed solely by the emergency physician. Comorbidities, rhythms, and management were obtained by chart review, and complicated patients (those with an acute underlying medical condition) were excluded by predefined criteria. Patient medications on ED presentations were obtained through the provincial Pharmanet database. Patients were stratified into CHADS 2 (congestive heart failure, hypertension, age > 75, diabetes, stroke/transient ischemic attack) scores, and the primary outcome was the proportion of higher-risk (CHADS 2 score >0) patients who were discharged home with the incorrect anticoagulation by the emergency physician. The secondary outcome was the number of lower-risk (CHADS 2=0) patients who began receiving warfarin by the emergency physician orders. The regional ED database was interrogated to ascertain the number of patients who had a stroke at 30 days. RESULTS Consecutive patients (1,090) were enrolled and 732 were discharged home with no cardiology consultation (657 fibrillation and 75 flutter). Of 151 higher-risk (CHADS 2 score >0) patients who should have been anticoagulated, 80 (53.0%; 95% confidence interval 44.7% to 61.0%) were discharged home from the ED without appropriate anticoagulation. In this group, 1 patient had an ischemic stroke at 24 days. Among 300 lower-risk patients (CHADS 2 score=0), 25 (8.3%; 95% confidence interval 5.6% to 12.2%) had warfarin initiated. CONCLUSION In this cohort of ED patients with uncomplicated atrial fibrillation or flutter who were discharged without cardiology involvement, many were not appropriately anticoagulated before ED arrival, and more than half of such patients did not appear to have corrective measures initiated by the emergency physician. This may represent a potential opportunity to improve patient care and outcomes.

Safety of Assessment of Patients With Potential Ischemic Chest Pain in an Emergency Department Waiting Room: A Prospective Comparative Cohort Study

STUDY OBJECTIVE Emergency department (ED) crowding has been associated with a variety of adverse outcomes. Current guidelines suggest that patients with potentially ischemic chest pain should undergo rapid assessment and treatment in a monitored setting to optimize the diagnosis of acute coronary syndrome. These patients may be at high risk of incorrect diagnosis and adverse events when their evaluation is delayed because of crowding. To mitigate crowding-related delays, we developed processes that enabled emergency physicians to evaluate potentially sick patients in the waiting room when all nurse-staffed stretchers are occupied. The objective of this study was to investigate the safety of waiting room chest pain evaluation. METHODS This prospective comparative cohort study was conducted in a busy urban, tertiary care ED. Explicit triage and waiting room evaluation processes were introduced. One thousand one hundred seven patients with chest pain of potential cardiac origin were triaged either to a monitored bed or a waiting room chair, depending on bed availability and triage judgment. After diagnostic evaluation, patients were followed for 30 days to identify the proportion of missed cases of acute coronary syndrome (primary outcome) and other prespecified adverse events. Analysis was based on intention to treat. RESULTS Eight hundred four patients were triaged to monitored bed and 303 to waiting room evaluation. Initial vital signs were similar, but the waiting room group was younger and had lower rates of some cardiovascular risk factors. The rate of acute coronary syndrome, defined as acute myocardial infarction or objective unstable angina, was 11.7% in the monitored bed group and 7.6% in waiting room patients. There were no missed acute coronary syndrome cases in either the monitored bed group (0%; 95% confidence interval [CI] 0% to 0.4%) or the waiting room group (0%; 95% CI 0% to 1.0%). There were 32 adverse events in the monitored bed group (4.0%; 95% CI 2.6% to 5.3%) and 2 in the waiting room group (0.7%; 95% CI 0% to 1.6%). CONCLUSION Our organized approach to triage and waiting room evaluation for stable chest pain patients was safe and efficient. Although waiting room evaluation is not ideal, it may be a feasible contingency strategy for periods when ED crowding compromises access to monitored, nurse-staffed ED beds.

Safety and Efficiency of Calcium Channel Blockers Versus Beta‐blockers for Rate Control in Patients With Atrial Fibrillation and No Acute Underlying Medical Illness

OBJECTIVES Many patients with atrial fibrillation (AF) are not candidates for rhythm control and may require rate control, typically with beta-blocking (BB) or calcium channel blocking (CCB) agents. Although these patients appear to have a low 30-day rate of stroke or death, it is unclear if one class of agent is safer or more effective. The objective was to determine whether BBs or CCBs would have a lower hospital admission rate and to measure 30-day safety outcomes including stroke, death, and emergency department (ED) revisits. METHODS This retrospective cohort study used a database from two urban EDs to identify consecutive patients with ED discharge diagnoses of AF from April 1, 2006, to March 31, 2010. Comorbidities, rhythms, management, and immediate outcomes were obtained by manual chart review, and patients with acute underlying medical conditions were excluded by predefined criteria. Patients managed only with rate control agents were eligible for review, and patients receiving BB agents were compared to those receiving CCB agents. The primary outcome was the proportion of patients requiring hospital admission; secondary outcomes included the ED length of stay (LOS), the proportion of patients having adverse events, the proportion of patients returning within 7 or 30 days, and the number of patients having a stroke or dying within 30 days. RESULTS A total of 259 consecutive patients were enrolled, with 100 receiving CCBs and 159 receiving BBs. Baseline demographics and comorbidities were similar. Twenty-seven percent of BB patients were admitted, and 31.0% of CCB patients were admitted (difference = 4.0%, 95% confidence interval [CI] = -7.7% to 16.1%), and there were no significant differences in ED LOS, adverse events, or 7- or 30-day ED revisits. One patient who received metoprolol had a stroke, and one patient who received diltiazem died within 30 days. CONCLUSIONS In this cohort of ED patients with AF and no acute underlying medical illness who underwent rate control only, patients receiving CCBs had similar hospital admission rates to those receiving BBs, while both classes of medications appeared equally safe at 30 days. Both CCBs and BBs are acceptable options for rate control.

Emergency Department Management and 1-Year Outcomes of Patients With Atrial Flutter

STUDY OBJECTIVE Atrial flutter is a common arrhythmia seen in the emergency department (ED), yet there is little research describing its management and outcomes. We analyze the success and safety of treatment of ED patients with atrial flutter. METHODS This was a retrospective cohort study obtained by searching the ED administrative database of 2 urban hospitals to identify consecutive patients with a primary discharge diagnosis of atrial flutter from April 1, 2006, to January 31, 2009. We linked each patients unique provincial health number to the provincial vital statistics registry and the regional ED database to identify subsequent deaths and strokes within 1 year. Manual chart review was conducted to confirm rhythms and outcomes and to identify patient comorbidities. Patients were stratified into 5 groups based on initial ED presentation and management approach: electrocardioversion, chemical cardioversion, spontaneous cardioversion, rate control only, and no acute ED arrhythmia-specific treatment. Primary outcome was the combined 1-year rate of stroke or death, and secondary outcomes included the proportion of eligible patients with conversion to normal sinus rhythm in each group and discharged to home. RESULTS Data from 122 consecutive patients with a primary ED diagnosis of atrial flutter were collected; there were 3 deaths and no strokes (2.5%; 95% confidence interval 0% to 5.1%) in the following year. Patients undergoing electrocardioversion achieved normal sinus rhythm 91% of the time, with 93% discharged home; patients undergoing oral or intravenous antiarrhythmic treatment achieved sinus rhythm 27% of the time, with 60% discharged home. Discharge rates of patients with spontaneous cardioversion, rate control, and no ED treatment were 93%, 58%, and 96%, respectively. CONCLUSION In this 2-center cohort of ED patients with atrial flutter, patients eligible for rhythm control had a higher success and lower admission rate with electrocardioversion than patients treated with antiarrhythmic medications. Overall, the majority of patients were discharged home. Deaths were typically related to concurrent medical illness rather than atrial flutter.