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Inconsistent electrocardiographic testing for syncope in United States emergency departments
Inconsistent Electrocardiographic Testing for Syncope in United States Emergency Departments Benjamin C. Sun, MD, MPP, Jennifer A. Emond, Carlos A. Camargo, Jr., MD, DrPH The electrocardiogram has diagnostic and prognostic value in the evaluation of syncope, and consensus guidelines suggest routine electrocardiographic testing. An analysis of a nationally representative survey suggests that electrocardiographic testing is performed inconsistently in patients presenting with syncope to United States emergency departments, even in high-risk patients, such as the elderly and hospitalized. Variation in electrocardiographic testing represents an opportunity to improve the care of patients presenting with syncope to emergency departments. 䊚2004 by Excerpta Medica, Inc. (Am J Cardiol 2004;93:1306 –1308)
yncope is a common presentation to United States (US) emergency departments and accounts for a S significant number of admissions. However, the 1
emergency department (ED) evaluation of syncope has substantial practice variation in diagnostic testing.2–7 The American College of Physicians (ACP) has offered guidelines for the initial evaluation of syncope, and recommendations include routine electrocardiographic (ECG) testing as an inexpensive and noninvasive diagnostic tool.3 ECG testing may also be important for prognosis and risk stratification.8,9 We assessed the frequency of ECG testing for patients presenting with syncope using a 9-year, nationally representative sample of US ED visits. •••
Data were obtained from the ED component of the National Hospital Ambulatory Medical Care Survey (NHAMCS) between 1992 and 2000. The combined data set represents estimates applied to approximately 865 million ED visits over a 9-year period. This survey is directed by the Centers for Disease Control and Prevention and the National Center for Health Statistics (NCHS). It is a national probability sample of noninstitutional, general, and short-stay hospitals (excluding federal, military, and veterans affairs hospitals). A 4-stage sampling strategy was used, which covered geographic primary sampling units, hospitals within primary sampling units, emergency departments within hospitals, and patients within emergency From the Department of Emergency Medicine, Massachusetts General Hospital, and the Department of Emergency Medicine and the Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts. This project was supported by the Richard C. Wuerz Scholarship for Emergency Medicine Research, Boston, Massachusetts. Dr. Sun’s address is: Department of Emergency Medicine, Brigham and Women’s Hospital, 75 Francis Street, Boston, Massachusetts 02115. E-mail: [email protected]. Manuscript received November 5, 2003; revised manuscript received and accepted February 2, 2004.
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©2004 by Excerpta Medica, Inc. All rights reserved. The American Journal of Cardiology Vol. 93 May 15, 2004
MS,
and
departments. The sample, consisting of 228,832 patients, was examined. Visits were randomly selected from 4-week reporting periods. The regional staff of the US Bureau of the Census supervised data collection. Data abstraction was performed centrally by experienced NCHS coders, with reported error rates of ⬍2% for the various fields.10 Data forms included up to 3 patient reasons for the visit and a list of administered tests, including an electrocardiogram, disposition, and demographic information. Analysis of the NHAMCS data set was approved by the human research committee. Patient reasons for visit are coded by using the Reason for Visit Classification for Ambulatory Care, a standardized sourcebook used in NCHS studies. Patient encounters were selected if any of the 3 patient reasons to visit included “1030.0 Fainting (syncope); includes blacking out, passing out, fainting spells; excludes unconsciousness.” Of all patients, 1,778 met this case definition for syncope. We determined point estimates and 95% confidence intervals for incidence of syncope in the emergency department and in national populations, admission rates, and prevalence of ECG testing. Nationally representative estimates were determined using NCHS-assigned patient weights, which adjust for the probability of selection and nonresponse. The NCHS suggests that estimates based on ⬍30 sample records be considered unreliable due to high relative SEs.11 US population estimates for calculating incidence per population were based on US Bureau of Census data. We assessed the univariate association of ECG testing with age, gender, race, ethnicity, US region, urban status, mode of arrival, presence of other reasons for a visit, and admission status. Binomial variables were analyzed by comparing point estimates and 95% confidence intervals. Categorical variables were analyzed with weighted chi-square analysis. Age was analyzed by 10-year intervals, and the association of age with ECG testing was performed by chi-square test for trend. The prevalence of ECG testing was also estimated before and after publication of ACP recommendations for routine ECG testing in 1997. Data management and analysis were performed with STATA 7.0 (STATA Corp., College Station, Texas). Over the 9-year study period, an estimated 6,662,000 patients (95% confidence interval 5,988,000 to 7,335,000) presented to US emergency departments with syncope, for an annual rate of 2.8 (95% confidence interval 2.5 to 3.1) per 1,000 individuals in the general population and 7.7 (95% confidence interval 6.9 to 8.5) per 1,000 ED visits. The average annual incidence was 740,000. Baseline char0002-9149/04/$–see front matter doi:10.1016/j.amjcard.2004.02.021
TABLE 1 Demographic Characteristics of Syncope Cases Presenting to the Emergency Department Between 1992 to 2000.
Characteristic Overall Age (yrs)† ⬍10 10–19 20–29 30–39 40–49 50–59 60–69 70–79 80⫹ Men‡ Women White Black Non-white Hispanic‡ Non-Hispanic
Absolute No. of Visits
Estimated No. of Visits (/1,000s)
%Total ED Syncope Visits
1,778
6,662
100
39 199 256 211 195 166 185 258 259 751 1,027 1,410 323 368 134 1,517
154 833 888 770 758 556 726 956 1,022 2,695 3,966 5,489 1,042 1,173 406 5,658
2 13 13 12 11 8 11 14 15 40 60 82 16 18 6 85
Rate per 1,000 US Individuals* (95% CI) 2.8 (2.5–3.1) 0.4 2.5 2.7 2.0 2.2 2.4 4.0 6.8 13.6 2.3 3.2 2.8 3.4 2.8 1.6 2.7
(0.2–0.7) (1.8–3.2) (2.0–3.3) (1.4–2.5) (1.7–2.7) (1.7–3.0) (2.7–5.3) (4.9–8.7) (10.5–16.7) (2.0–2.6) (2.8–3.7) (2.5–3.1) (2.6–4.1) (2.2–3.3) (1.0–2.2) (2.4–2.9)
Rate per 1,000 ED Visits* (95% CI) 7.7 (6.9–8.5) 1.0 7.7 6.1 5.7 7.6 8.6 14.0 17.8 21.8 6.6 8.7 8.2 5.9 5.9 4.5 8.2
(0.5–1.4) (5.5–9.9) (4.5–7.6) (4.0–7.3) (5.9–9.2) (6.3–10.9) (9.5–18.5) (12.7–22.8) (16.8–26.8) (5.6–7.5) (7.6–9.8) (7.3–9.1) (4.6–7.2) (4.6–7.1) (2.7–6.2) (7.3–9.1)
*Strata-matched rates. † Weighted chi-square (p ⬍0.001) for ED incidence estimates. ‡ Nonoverlapping 95% confidence intervals among strata for population and ED incidence estimates. CI ⫽ confidence interval.
TABLE 2 Electrocardiographic Testing Among Syncope Visits, Stratified by Age* Age (yrs) ⬍20 20–29 30–39 40–49 50–59 60–69 70–79 ⱖ80
Underwent Electrocardiography
95% CI
33% 28% 45% 56% 69% 77% 80% 83%
24–42 16–39 32–58 46–65 55–83 69–86 69–91 78–89
*Chi-square test for trend: p ⬍0.001. Abbreviation as in Table 1.
acteristics of patients presenting with syncope are presented in Table 1. Of ED patients with syncope, 32% (95% confidence interval 28 to 36) were admitted, and syncope admissions accounted for 1.9% (95% confidence interval 1.6 to 2.2) of total ED admissions. ECG testing was documented in only 59% (95% confidence interval 54 to 63) of ED syncope visits. Advancing age was significantly associated with ECG testing (Table 2). Of admitted patients, 79% (95% confidence interval 74 to 85) underwent ECG testing compared with 49% (95% confidence interval 44 to 54) of patients who were not admitted (p ⬍0.001). Further stratification of admitted patients by age did not demonstrate significant differences across age intervals (data not shown). None of the other predefined variables was found to be significantly associated with ECG testing. Patient subgroups with specific concurrent reasons for visit, including seizure and stroke or transient ischemic attack, were too small to reliably analyze (n ⬍30) and were not studied further. We also
examined trends over the 9-year period. ECG testing from 1992 to 1997, before publication of ACP recommendations,3 was performed in 57% (95% confidence interval 53 to 60) of syncope visits compared with 61% (95% confidence interval 57 to 65) from 1998 to 2000 (p ⫽ 0.19). •••
This is the largest and most generalizable study to date on ECG testing variation in ED syncope visits. Using recent data from a nationally representative survey, we demonstrated that syncope is a common reason for ED visits and hospitalizations, and that many ED patients presenting with syncope do not receive ECG testing. ECG testing is performed inconsistently even in high-risk patients, including the elderly and admitted patients. Publication of ACP guidelines advocating routine ECG testing appears to have had little effect in the ED setting. There are several limitations. First, ECG testing may have been performed but not documented in the chart. This would lead to an underestimate of ECG testing. However, poor documentation is unlikely to account for the observed magnitude of failure to perform ECG testing, especially for a potentially lifethreatening presentation such as syncope. Second, small subgroup samples limit the ability to reliably analyze patients with syncope with other reasons for visits. Specific subgroups of interest include patients with complaints that may provide an obvious reason for syncope, including seizure and transient ischemic attack or stroke. However, we excluded patients with concurrent seizure and transient ischemic attack or stroke in an exploratory analysis and found similar associations between ECG testing and predefined covariates (data not shown). Third, there are no clinical outcome variables in this survey, including mortality BRIEF REPORTS
1307
rate, rate of myocardial ischemia, pacemaker or automatic implantable cardioverter defibrillators insertion, or initiation of antiarrhythmic medications. The association between ECG testing and these outcomes needs to be assessed in future studies. 1. Schnipper JL, Kapoor WN. Diagnostic evaluation and management of patients with syncope. Med Clin North Am 2001;85:423–456. 2. American College of Emergency Physicians Clinical Policies Committee. Clinical policy: critical issues in the evaluation and management of patients presenting with syncope. Ann Emerg Med 2001;37:771–776. 3. Linzer M, Yang EH, Estes NA III, Wang P, Vorperian VR, Kapoor WN. Diagnosing syncope. Part 1: value of history, physical examination, and electrocardiography. Clinical Efficacy Assessment Project of the American College of Physicians. Ann Intern Med 1997;126:989 –996. 4. Ammirati F, Colivicchi F, Santini M. Diagnosing syncope in clinical practice: Implementation of a simplified diagnostic algorithm in a multicentre prospective
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trial—the OESIL 2 study (Osservatorio Epidemiologico della Sincope nel Lazio). Eur Heart J 2000;21:935–940. 5. Blanc JJ, L’Her C, Touiza A, Garo B, L’Her E, Mansourati J. Prospective evaluation and outcome of patients admitted for syncope over a 1 year period. Eur Heart J 2002;23:815–820. 6. Crane SD. Risk stratification of patients with syncope in an accident and emergency department. Emerg Med J 2002;19:23–27. 7. Thakore SB, Crombie I, Johnston M. The management of syncope in a British emergency department compared to recent American guidelines. Scott Med J 1999;44:155–157. 8. Martin TP, Hanusa BH, Kapoor WN. Risk stratification of patients with syncope. Ann Emerg Med 1997;29:459 –466. 9. Colivicchi F, Ammirati F, Melina D, Guido V, Imperoli G, Santini M. Development and prospective validation of a risk stratification system for patients with syncope in the emergency department: the OESIL risk score. Eur Heart J 2003;24:811–819. 10. McCraig LBC. 1999 Emergency Department Summary. Advance Data From Vital and Health Statistics, No. 320. Hyattsville, MD: US Department of Health and Human Services, 2001. 11. 2000 NHAMCS Micro-Data File Documentation. Hyattsville, MD: National Center for Health Statistics; 2000.
MAY 15, 2004
yncope is a common presentation to United States (US) emergency departments and accounts for a S significant number of admissions. However, the 1
emergency department (ED) evaluation of syncope has substantial practice variation in diagnostic testing.2–7 The American College of Physicians (ACP) has offered guidelines for the initial evaluation of syncope, and recommendations include routine electrocardiographic (ECG) testing as an inexpensive and noninvasive diagnostic tool.3 ECG testing may also be important for prognosis and risk stratification.8,9 We assessed the frequency of ECG testing for patients presenting with syncope using a 9-year, nationally representative sample of US ED visits. •••
Data were obtained from the ED component of the National Hospital Ambulatory Medical Care Survey (NHAMCS) between 1992 and 2000. The combined data set represents estimates applied to approximately 865 million ED visits over a 9-year period. This survey is directed by the Centers for Disease Control and Prevention and the National Center for Health Statistics (NCHS). It is a national probability sample of noninstitutional, general, and short-stay hospitals (excluding federal, military, and veterans affairs hospitals). A 4-stage sampling strategy was used, which covered geographic primary sampling units, hospitals within primary sampling units, emergency departments within hospitals, and patients within emergency From the Department of Emergency Medicine, Massachusetts General Hospital, and the Department of Emergency Medicine and the Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts. This project was supported by the Richard C. Wuerz Scholarship for Emergency Medicine Research, Boston, Massachusetts. Dr. Sun’s address is: Department of Emergency Medicine, Brigham and Women’s Hospital, 75 Francis Street, Boston, Massachusetts 02115. E-mail: [email protected]. Manuscript received November 5, 2003; revised manuscript received and accepted February 2, 2004.
1306
©2004 by Excerpta Medica, Inc. All rights reserved. The American Journal of Cardiology Vol. 93 May 15, 2004
MS,
and
departments. The sample, consisting of 228,832 patients, was examined. Visits were randomly selected from 4-week reporting periods. The regional staff of the US Bureau of the Census supervised data collection. Data abstraction was performed centrally by experienced NCHS coders, with reported error rates of ⬍2% for the various fields.10 Data forms included up to 3 patient reasons for the visit and a list of administered tests, including an electrocardiogram, disposition, and demographic information. Analysis of the NHAMCS data set was approved by the human research committee. Patient reasons for visit are coded by using the Reason for Visit Classification for Ambulatory Care, a standardized sourcebook used in NCHS studies. Patient encounters were selected if any of the 3 patient reasons to visit included “1030.0 Fainting (syncope); includes blacking out, passing out, fainting spells; excludes unconsciousness.” Of all patients, 1,778 met this case definition for syncope. We determined point estimates and 95% confidence intervals for incidence of syncope in the emergency department and in national populations, admission rates, and prevalence of ECG testing. Nationally representative estimates were determined using NCHS-assigned patient weights, which adjust for the probability of selection and nonresponse. The NCHS suggests that estimates based on ⬍30 sample records be considered unreliable due to high relative SEs.11 US population estimates for calculating incidence per population were based on US Bureau of Census data. We assessed the univariate association of ECG testing with age, gender, race, ethnicity, US region, urban status, mode of arrival, presence of other reasons for a visit, and admission status. Binomial variables were analyzed by comparing point estimates and 95% confidence intervals. Categorical variables were analyzed with weighted chi-square analysis. Age was analyzed by 10-year intervals, and the association of age with ECG testing was performed by chi-square test for trend. The prevalence of ECG testing was also estimated before and after publication of ACP recommendations for routine ECG testing in 1997. Data management and analysis were performed with STATA 7.0 (STATA Corp., College Station, Texas). Over the 9-year study period, an estimated 6,662,000 patients (95% confidence interval 5,988,000 to 7,335,000) presented to US emergency departments with syncope, for an annual rate of 2.8 (95% confidence interval 2.5 to 3.1) per 1,000 individuals in the general population and 7.7 (95% confidence interval 6.9 to 8.5) per 1,000 ED visits. The average annual incidence was 740,000. Baseline char0002-9149/04/$–see front matter doi:10.1016/j.amjcard.2004.02.021
TABLE 1 Demographic Characteristics of Syncope Cases Presenting to the Emergency Department Between 1992 to 2000.
Characteristic Overall Age (yrs)† ⬍10 10–19 20–29 30–39 40–49 50–59 60–69 70–79 80⫹ Men‡ Women White Black Non-white Hispanic‡ Non-Hispanic
Absolute No. of Visits
Estimated No. of Visits (/1,000s)
%Total ED Syncope Visits
1,778
6,662
100
39 199 256 211 195 166 185 258 259 751 1,027 1,410 323 368 134 1,517
154 833 888 770 758 556 726 956 1,022 2,695 3,966 5,489 1,042 1,173 406 5,658
2 13 13 12 11 8 11 14 15 40 60 82 16 18 6 85
Rate per 1,000 US Individuals* (95% CI) 2.8 (2.5–3.1) 0.4 2.5 2.7 2.0 2.2 2.4 4.0 6.8 13.6 2.3 3.2 2.8 3.4 2.8 1.6 2.7
(0.2–0.7) (1.8–3.2) (2.0–3.3) (1.4–2.5) (1.7–2.7) (1.7–3.0) (2.7–5.3) (4.9–8.7) (10.5–16.7) (2.0–2.6) (2.8–3.7) (2.5–3.1) (2.6–4.1) (2.2–3.3) (1.0–2.2) (2.4–2.9)
Rate per 1,000 ED Visits* (95% CI) 7.7 (6.9–8.5) 1.0 7.7 6.1 5.7 7.6 8.6 14.0 17.8 21.8 6.6 8.7 8.2 5.9 5.9 4.5 8.2
(0.5–1.4) (5.5–9.9) (4.5–7.6) (4.0–7.3) (5.9–9.2) (6.3–10.9) (9.5–18.5) (12.7–22.8) (16.8–26.8) (5.6–7.5) (7.6–9.8) (7.3–9.1) (4.6–7.2) (4.6–7.1) (2.7–6.2) (7.3–9.1)
*Strata-matched rates. † Weighted chi-square (p ⬍0.001) for ED incidence estimates. ‡ Nonoverlapping 95% confidence intervals among strata for population and ED incidence estimates. CI ⫽ confidence interval.
TABLE 2 Electrocardiographic Testing Among Syncope Visits, Stratified by Age* Age (yrs) ⬍20 20–29 30–39 40–49 50–59 60–69 70–79 ⱖ80
Underwent Electrocardiography
95% CI
33% 28% 45% 56% 69% 77% 80% 83%
24–42 16–39 32–58 46–65 55–83 69–86 69–91 78–89
*Chi-square test for trend: p ⬍0.001. Abbreviation as in Table 1.
acteristics of patients presenting with syncope are presented in Table 1. Of ED patients with syncope, 32% (95% confidence interval 28 to 36) were admitted, and syncope admissions accounted for 1.9% (95% confidence interval 1.6 to 2.2) of total ED admissions. ECG testing was documented in only 59% (95% confidence interval 54 to 63) of ED syncope visits. Advancing age was significantly associated with ECG testing (Table 2). Of admitted patients, 79% (95% confidence interval 74 to 85) underwent ECG testing compared with 49% (95% confidence interval 44 to 54) of patients who were not admitted (p ⬍0.001). Further stratification of admitted patients by age did not demonstrate significant differences across age intervals (data not shown). None of the other predefined variables was found to be significantly associated with ECG testing. Patient subgroups with specific concurrent reasons for visit, including seizure and stroke or transient ischemic attack, were too small to reliably analyze (n ⬍30) and were not studied further. We also
examined trends over the 9-year period. ECG testing from 1992 to 1997, before publication of ACP recommendations,3 was performed in 57% (95% confidence interval 53 to 60) of syncope visits compared with 61% (95% confidence interval 57 to 65) from 1998 to 2000 (p ⫽ 0.19). •••
This is the largest and most generalizable study to date on ECG testing variation in ED syncope visits. Using recent data from a nationally representative survey, we demonstrated that syncope is a common reason for ED visits and hospitalizations, and that many ED patients presenting with syncope do not receive ECG testing. ECG testing is performed inconsistently even in high-risk patients, including the elderly and admitted patients. Publication of ACP guidelines advocating routine ECG testing appears to have had little effect in the ED setting. There are several limitations. First, ECG testing may have been performed but not documented in the chart. This would lead to an underestimate of ECG testing. However, poor documentation is unlikely to account for the observed magnitude of failure to perform ECG testing, especially for a potentially lifethreatening presentation such as syncope. Second, small subgroup samples limit the ability to reliably analyze patients with syncope with other reasons for visits. Specific subgroups of interest include patients with complaints that may provide an obvious reason for syncope, including seizure and transient ischemic attack or stroke. However, we excluded patients with concurrent seizure and transient ischemic attack or stroke in an exploratory analysis and found similar associations between ECG testing and predefined covariates (data not shown). Third, there are no clinical outcome variables in this survey, including mortality BRIEF REPORTS
1307
rate, rate of myocardial ischemia, pacemaker or automatic implantable cardioverter defibrillators insertion, or initiation of antiarrhythmic medications. The association between ECG testing and these outcomes needs to be assessed in future studies. 1. Schnipper JL, Kapoor WN. Diagnostic evaluation and management of patients with syncope. Med Clin North Am 2001;85:423–456. 2. American College of Emergency Physicians Clinical Policies Committee. Clinical policy: critical issues in the evaluation and management of patients presenting with syncope. Ann Emerg Med 2001;37:771–776. 3. Linzer M, Yang EH, Estes NA III, Wang P, Vorperian VR, Kapoor WN. Diagnosing syncope. Part 1: value of history, physical examination, and electrocardiography. Clinical Efficacy Assessment Project of the American College of Physicians. Ann Intern Med 1997;126:989 –996. 4. Ammirati F, Colivicchi F, Santini M. Diagnosing syncope in clinical practice: Implementation of a simplified diagnostic algorithm in a multicentre prospective
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trial—the OESIL 2 study (Osservatorio Epidemiologico della Sincope nel Lazio). Eur Heart J 2000;21:935–940. 5. Blanc JJ, L’Her C, Touiza A, Garo B, L’Her E, Mansourati J. Prospective evaluation and outcome of patients admitted for syncope over a 1 year period. Eur Heart J 2002;23:815–820. 6. Crane SD. Risk stratification of patients with syncope in an accident and emergency department. Emerg Med J 2002;19:23–27. 7. Thakore SB, Crombie I, Johnston M. The management of syncope in a British emergency department compared to recent American guidelines. Scott Med J 1999;44:155–157. 8. Martin TP, Hanusa BH, Kapoor WN. Risk stratification of patients with syncope. Ann Emerg Med 1997;29:459 –466. 9. Colivicchi F, Ammirati F, Melina D, Guido V, Imperoli G, Santini M. Development and prospective validation of a risk stratification system for patients with syncope in the emergency department: the OESIL risk score. Eur Heart J 2003;24:811–819. 10. McCraig LBC. 1999 Emergency Department Summary. Advance Data From Vital and Health Statistics, No. 320. Hyattsville, MD: US Department of Health and Human Services, 2001. 11. 2000 NHAMCS Micro-Data File Documentation. Hyattsville, MD: National Center for Health Statistics; 2000.
MAY 15, 2004