Draft Recommendation Statement
Cardiovascular Disease Risk: Screening With Electrocardiography
This opportunity for public comment expired on January 22, 2018 at 8:00 PM EST
Note: This is a Draft Recommendation Statement. This draft is distributed solely for the purpose of receiving public input. It has not been disseminated otherwise by the USPSTF. The final Recommendation Statement will be developed after careful consideration of the feedback received and will include both the Research Plan and Evidence Review as a basis.
Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.
Draft: Recommendation Summary
|Adults at low risk of CVD events|
The USPSTF recommends against screening with resting or exercise electrocardiography (ECG) to prevent cardiovascular disease (CVD) events in asymptomatic adults at low risk of CVD events.
|Adults at intermediate or high risk of CVD events|
The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening with resting or exercise ECG to prevent CVD events in asymptomatic adults at intermediate or high risk of CVD events.
Read the plain-language consumer summary of the draft Recommendation Statement.
The U.S. Preventive Services Task Force (USPSTF) makes recommendations about the effectiveness of specific clinical preventive services for patients without obvious related signs or symptoms.
It bases its recommendations on the evidence of both the benefits and harms of the service and an assessment of the balance. The USPSTF does not consider the costs of providing a service in this assessment.
The USPSTF recognizes that clinical decisions involve more considerations than evidence alone. Clinicians should understand the evidence but individualize decision making to the specific patient or situation. Similarly, the USPSTF notes that policy and coverage decisions involve considerations in addition to the evidence of clinical benefits and harms.
CVD is the most common cause of death among adults in the United States. Treatment to prevent CVD events by modifying risk factors is currently informed by CVD risk assessment with tools such as the Framingham Risk Score or the Pooled Cohort Equations, which stratify individual risk to inform treatment decisions. If existing CVD risk assessment tools could be improved, treatment might be better targeted, thereby maximizing the benefits of screening and minimizing the harms.
The USPSTF found inadequate evidence to determine whether adding exercise or resting ECG to conventional risk factor assessment leads to improved risk stratification of individuals to inform treatment decisions.
Benefits of Early Detection and Intervention and Treatment
The USPSTF found inadequate evidence to determine whether the incremental information offered by resting or exercise ECG (beyond that obtained with traditional CVD risk factors) can be used to guide treatment decisions and ultimately reduce CVD events.
Based on the epidemiology and natural history of CVD, and established treatment strategies based on risk stratification, it is unlikely that the benefits of screening with resting or exercise ECG in asymptomatic adults at low risk of CVD events are greater than small.
Harms of Early Detection and Intervention and Treatment
The USPSTF found adequate evidence that screening with resting or exercise ECG in asymptomatic adults leads to harms that are at least small and may be moderate, including unnecessary invasive procedures, overtreatment, and labeling.
The USPSTF concludes with moderate certainty that the potential harms of screening with resting or exercise ECG to prevent CVD events equal or exceed the potential benefits in asymptomatic adults at low risk of CVD events.
The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening with resting or exercise ECG to prevent CVD events in asymptomatic adults at intermediate or high risk of CVD.
Draft: Clinical Considerations
Patient Population Under Consideration
This recommendation applies to adults without symptoms of or a diagnosis of CVD.
Suggestions for Practice Regarding the I Statement
In deciding whether to screen with resting or exercise ECG in asymptomatic adults at intermediate or high risk of CVD events, clinicians should consider the following information.
Potential Preventable Burden
Although evidence is insufficient to determine whether screening with ECG in adults is beneficial, those who may be at increased risk of CVD events might have the greatest potential for net benefit. Reclassification into a higher risk category might lead to more intensive medical management that could lower the risk of CVD events, but it might also result in harms, including adverse medication effects such as gastrointestinal bleeding and hepatic injury. Regardless of ECG findings, persons who are already at high risk of CVD events should receive intensive risk factor modification. Persons who are classified as low risk are unlikely to benefit from screening with ECG.
For persons in certain occupations, such as pilots and operators of heavy equipment, for whom sudden incapacitation or death may endanger the safety of others, considerations other than the health benefit to the patient may influence the decision to screen with ECG to prevent CVD events.
In all risk groups, an abnormal ECG finding (either a true- or false-positive result) can lead to invasive confirmatory testing and treatment that have the potential for serious harm, including unnecessary radiation exposure. Two studies of asymptomatic adults with diabetes reported that 6% and 12% of patients who were screened with exercise ECG went on to receive angiography, and 3% to 5% underwent revascularization, without evidence of benefit to the study patients.1, 2 Angiography and revascularization are associated with harms, including bleeding, contrast-induced nephropathy, cardiac arrhythmia, stroke, myocardial infarction, coronary artery dissection, allergic reaction to the contrast agent, and death.
Although many guideline groups recommend cardiovascular risk assessment, there are few data on how this is applied in clinical practice. Only 41% of respondents in a survey of more than 900 U.S. physicians reported using cardiovascular risk prediction equations in practice.3 There are few data on the use of ECG to assess CVD risk in asymptomatic patients in the United States. A Canadian retrospective cohort study from 2010 to 2015 found that 21.5% of low-risk primary care patients were screened with ECG within 30 days of an annual health examination, and the proportion of patients screened with ECG varied across clinics from 1.8% to 76.1%.4
Assessment of Risk
Accurate identification of persons at high risk of CVD events provides the opportunity for more intensive risk factor management to reduce the likelihood of such an event. In addition, identifying persons at low risk may allow for a reduction in interventions among patients who are not likely to benefit from them.
Several factors are associated with an increased risk of CVD events, including older age, male sex, high blood pressure, current smoking, abnormal lipid levels, diabetes, obesity, and physical inactivity. Risk factors are combined in many ways to estimate a person's risk of a CVD event. Several calculators and models are available to quantify a person's 10-year risk of CVD events. The Framingham Risk Score,5 based on data from the Framingham Heart Study, was one of the first widely used CVD risk assessment tools. Persons with a 10-year CVD event risk greater than 20% are generally considered high risk, those with a 10-year CVD event risk less than 10% are considered low risk, and those with a 10-year CVD event risk of 10% to 20% are considered intermediate risk. The Pooled Cohort Equations, introduced by the American College of Cardiology and American Heart Association in 2013, include the same variables as the Framingham Risk Score, as well as race/ethnicity and diabetes. Persons with a 10-year CVD event risk less than 7.5% are considered at low risk, and those with a 10-year CVD event risk of 7.5% or greater are considered at elevated risk.6
Both resting and exercise ECG are used for the diagnostic evaluation of suspected CVD, which has led to the suggestion that they could also be used to screen asymptomatic persons to identify those who would benefit from earlier, more intensive management of modifiable risk factors, preventive interventions, or both. Resting ECG records cardiac electrical activity while the patient is at rest, over a short period of time. Standard ECG testing is performed with 12 leads, although some tests use fewer leads. More recently, ECG leads have been built into blood pressure cuffs, smart phones, and other devices. Exercise ECG records cardiac electrical activity during physical exertion, often at a prespecified intensity level. The most common method of exercise ECG is the treadmill test, but other methods, such as bicycles and ergometers, have also been used. Both resting and exercise ECG look for markers of previous myocardial infarction, myocardial ischemia, and other cardiac abnormalities (such as left ventricular hypertrophy, bundle branch block, or arrhythmia) that may be associated with CVD or predict future CVD events.
Treatment and Interventions
Asymptomatic adults at increased risk of CVD are usually treated with a combination of diet and exercise modifications, lipid-lowering medications, aspirin, hypertension management, and interventions to encourage tobacco cessation. Recommendations for diet and exercise modifications, lipid-lowering medications, and aspirin are based on level of cardiovascular risk. Recent guidelines also recommend risk stratification of hypertension treatment;7 the recommendation for tobacco cessation applies to all persons regardless of CVD risk.
The USPSTF has made recommendations on many factors related to CVD prevention, including screening for high blood pressure,8 use of statins,9 counseling on smoking cessation,10 and counseling to promote healthful diet and physical activity.11 In addition, the USPSTF recommends low-dose aspirin use in persons at increased risk of CVD.12
Draft: Other Considerations
Research Needs and Gaps
There is already a considerable amount of studies reporting hazard ratios and other measures of association between ECG changes and cardiovascular outcomes, so additional studies of this nature are unlikely to advance the field. Studies are needed that assess the incremental value of adding ECG to current CVD risk assessment tools or instruments to directly inform decisionmaking, and studies that examine patient outcomes would be most useful. Failing that, studies are needed that assess the added value of ECG for risk reclassification across clinically-relevant risk thresholds. Any study of CVD risk assessment should also evaluate harms associated with assessment as well as those related to additional testing and treatment. Studies that measure risk reclassification should report total, event, and nonevent Net Reclassification Indices, with corresponding CIs, as well as measures of calibration and discrimination.
Burden of Disease
CVD is the most common cause of death among adults in the United States, accounting for 1 in 3 deaths. Although it remains a significant cause of illness and death, CVD mortality has been decreasing over time in the United States. Currently, the annual incidence of new cases of myocardial infarction and cerebral vascular accident in the United States is 580,000 and 610,000, respectively.16
Scope of Review
In 2012, the USPSTF recommended against screening for coronary heart disease with ECG in low-risk adults (D recommendation) and issued an I statement for intermediate- and high-risk adults.17 To update the prior recommendations, the USPSTF requested the current evidence review. In recognition of how the field has advanced, the current evidence review18 did not include association studies but addressed whether the addition of screening with resting or exercise ECG improves health outcomes compared with traditional CVD risk assessment in asymptomatic adults.
Accuracy of Screening Tests
The USPSTF reviewed the evidence on whether screening with resting or exercise ECG improves calibration, discrimination, or risk reclassification when added to CVD risk assessment models using traditional risk factors. The USPSTF focused on evidence that ECG adds to current CVD risk assessment with the Framingham Risk Score or the Pooled Cohort Equations, because this could lead to change in treatments for patients.
The USPSTF identified five cohort studies (two of which overlap with the previous review) that evaluated whether adding exercise ECG to current CVD risk assessment improves calibration, discrimination, or reclassification. Four studies assessed whether exercise ECG improved calibration; two studies compared ECG added to the Framingham Risk Score19, 20 and the other two compared ECG added to other risk assessment models.21, 22 The studies used different measures and showed mixed effects on calibration. Three studies assessed whether adding exercise ECG to the Framingham Risk Score20 or other risk assessment models21, 23 improved discrimination, all of which found only small absolute improvements in area under the curve or c-statistic (0.02 to 0.03). Only one risk assessment model development study evaluated whether adding exercise ECG improved risk reclassification. However, it did not apply the risk thresholds that currently determine treatment, and only reported overall reclassification, not event and nonevent net reclassification.21
The USPSTF identified nine cohort studies (one of which overlapped with the previous review) that evaluated whether adding resting ECG to current CVD risk assessment improves calibration, discrimination, or reclassification, five of which evaluated multiple ECG changes and four of which evaluated a single ECG change. Five studies evaluated adding resting ECG to the Framingham Risk Score,24-28 and one of these studies28 also evaluated adding resting ECG to the Pooled Cohort Equations. Adding resting ECG to existing CVD risk assessment models improved calibration for several CVD outcomes, although the strength of evidence was low, and resulted in small or very small improvements in discrimination (absolute improvement, 0.001 to 0.050). Two studies reported net reclassification when resting ECG was added to the Framingham Risk Score,18, 25, 26 and one study28 evaluated adding resting ECG to both the Framingham Risk Score and the Pooled Cohort Equations. There was a small to moderate improvement in reclassification, but the studies did not present the full reclassification data, so it is difficult to determine whether the reclassification would change treatment. No two studies evaluated the same CVD risk assessment model, risk category threshold, or outcome.
Effectiveness of Early Detection and Treatment
The USPSTF identified no studies that directly assessed whether adding resting ECG to current CVD risk assessment improves cardiovascular outcomes for any risk group.18 The USPSTF identified two fair-quality randomized, controlled trials of screening with exercise ECG in persons with diabetes (and therefore at increased risk of CVD) that found no difference in mortality or cardiovascular events.1, 2 However, both trials fell far short of their intended enrollment and therefore were underpowered and had a relatively short time period (mean, 3.5 years) to detect a difference in cardiovascular outcomes.
Potential Harms of Screening and Treatment
Resting ECG has the potential for anxiety and labeling; however, the USPSTF was unable to find relevant studies on these harms. Exercise ECG has more potential for direct harms (e.g., triggering a cardiovascular event or musculoskeletal injury) but survey data of symptomatic patients suggests these harms are very rare.29, 30 The primary concern for both types of ECG screening is the harm of subsequent procedures or interventions initiated as a result of screening (e.g., angiography or revascularization procedures). Only one study reported harms of subsequent testing (1 of 12 patients referred for revascularization had a nonfatal myocardial infarction);2 therefore, the USPSTF looked at a broader range of study designs to estimate potential harms.
Angiography rates following screening with exercise ECG in asymptomatic populations are generally less than 3% (range, 0.6% to 13%). The majority of patients undergoing angiography in these studies did not have angiographically demonstrable coronary artery stenosis, but some did go on to revascularization (0.1% to 0.5%).18 Based on large, population-based registries that include symptomatic persons, angiography is associated with a serious harm rate of 1.7%, including arrhythmia (0.40%), death (0.10%), stroke (0.07%), and myocardial infarction (0.05%). Revascularization increases the risk of periprocedural myocardial infarction (1.7%), coronary artery dissection (1.3%), bleeding events within 72 hours (1.3%), vascular complications (0.4%), renal failure (0.4%), stroke (0.1%), and death on day of procedure (<0.01%).18 The USPSTF did not find any recent studies that directly address the potential harms of anxiety or labeling.
Estimate of Magnitude of Net Benefit
For asymptomatic adults at low risk of CVD events, it is very unlikely that the information from resting or exercise ECG (beyond that obtained with conventional CVD risk factors) will result in a change in the patient's risk category that would lead to a change in treatment and ultimately improve health outcomes. Serious possible harms are associated with resting or exercise ECG, specifically the potential adverse effects of subsequent invasive testing. Therefore, the USPSTF concluded with moderate certainty that screening with ECG in asymptomatic, low-risk persons provides no net benefit.
For asymptomatic adults at intermediate or high risk of CVD events, there is insufficient evidence to determine the extent to which information from resting or exercise ECG adds to current CVD risk assessment (Pooled Cohort Equations) and whether it results in a change in risk management and ultimately reduces CVD events. As with low-risk adults, serious possible harms are associated with screening with resting or exercise ECG in asymptomatic adults at intermediate or high risk, and thus the USPSTF could not assess the net benefit of screening with ECG.
How Does Evidence Fit With Biological Understanding?
There is substantial and consistent evidence that identifying and treating traditional, modifiable CVD risk factors, such as high blood pressure, abnormal lipid levels, diabetes, current smoking, physical inactivity, and diet improve cardiovascular outcomes. These risk factors are linked to the biological understanding of the pathophysiology of CVD. ECG measures the electrical activity in the heart and results can be abnormal for many reasons, only some of which are due to atherosclerotic CVD. In low-risk patients, these abnormalities are unlikely to result from atherosclerotic CVD; in intermediate- and high-risk patients, they are more likely to result from atherosclerotic CVD, but there is no evidence that targeting these abnormalities in addition to modifiable risk factors has benefit.
Draft: Update of Previous USPSTF Recommendation
This recommendation is an update of the 2012 USPSTF recommendation. As in 2012, the USPSTF continues to recommend against screening with ECG for coronary heart disease in low-risk adults, and the evidence remains insufficient on screening in adults at increased risk.17
Draft: Recommendations of Others
The American College of Physicians recommends against screening for CVD with resting or stress ECG in asymptomatic, low-risk adults.31 The American College of Cardiology concludes that exercise ECG is rarely appropriate in asymptomatic adults at low global risk of CVD events, may be an appropriate option for adults at intermediate risk, and is appropriate for adults at high risk.32 The American Academy of Family Physicians is currently updating its recommendation.33 The American College of Preventive Medicine recommends against routinely screening with resting or exercise ECG in the general adult population.34
1. Lièvre MM, Moulin P, Thivolet C, et al; DYNAMIT investigators. Detection of silent myocardial ischemia in asymptomatic patients with diabetes: results of a randomized trial and meta-analysis assessing the effectiveness of systematic screening. Trials. 2011;12:23.
2. Turrini F, Scarlini S, Mannucci C, et al. Does coronary atherosclerosis deserve to be diagnosed early in diabetic patients? The DADDY-D trial. Screening diabetic patients for unknown coronary disease. Eur J Intern Med. 2015;26(6):407-13.
3. National Heart, Lung, and Blood Institute. Assessing Cardiovascular Risk: Systematic Evidence Review From the Risk Assessment Work Group. https://www.nhlbi.nih.gov/health-pro/guidelines/in-develop/cardiovascular-risk-reduction/risk-assessment/. 2013. Accessed December 7, 2017.
4. Bhatia RS, Bouck Z, Ivers NM, et al. Electrocardiograms in low-risk patients undergoing an annual health examination. JAMA Intern Med. 2017;177(9):1326-33.
5. Framingham Heart Study. Cardiovascular Disease (10-Year Risk) Calculator. https://www.framinghamheartstudy.org/risk-functions/cardiovascular-disease/10-year-risk.php#. 2017. Accessed December 7, 2017.
6. Goff DC Jr, Lloyd-Jones DM, Bennett G, et al; American College of Cardiology/American Heart Association Task Force on Practice Guidelines. 2013 ACC/AHA guideline on the assessment of cardiovascular risk: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2014;63(25 Pt B):2935-59.
7. Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol. 2017;Nov 7. pii: S0735-1097(17)41519-1 (Epub ahead of print)
8. U.S. Preventive Services Task Force. Screening for high blood pressure in adults: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2015;163(10):778-86.
9. US Preventive Services Task Force. Statin use for the primary prevention of cardiovascular disease in adults: US Preventive Services Task Force recommendation statement. JAMA. 2016;316(19):1997-2007.
10. U.S. Preventive Services Task Force. Behavioral and pharmacotherapy interventions for tobacco smoking cessation in adults, including pregnant women: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2015;163(8):622-34.
11. U.S. Preventive Services Task Force. Behavioral counseling to promote a healthful diet and physical activity for cardiovascular disease prevention in adults with cardiovascular risk factors: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2014;161(8):587-93.
12. U.S. Preventive Services Task Force. Aspirin use for the primary prevention of cardiovascular disease and colorectal cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2016;164(12):836-45.
13. National Heart, Lung, and Blood Institute. Heart and Vascular Resources. https://www.nhlbi.nih.gov/health-pro/resources/heart. Accessed December 7, 2017.
14. Centers for Disease Control and Prevention. Prevention Works: CDC Strategies for a Heart-Healthy and Stroke-Free America. https://www.cdc.gov/dhdsp/prevention_works.htm. 2013. Accessed December 7, 2017.
15. Healthy People 2020. Evidence-Based Resources. https://www.healthypeople.gov/2020/tools-resources/Evidence-Based-Resources. Accessed December 7, 2017.
16. Benjamin EJ, Blaha MJ, Chiuve SE, et al; American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Heart disease and stroke statistics--2017 update: a report from the American Heart Association. Circulation. 2017;135(10):e146-e603.
17. U.S. Preventive Services Task Force. Screening for coronary heart disease with electrocardiography: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2012;157(7):512-8.
18. Jonas DE, Reddy S, Middleton JC, et. al. Screening for Cardiovascular Disease Risk With Electrocardiography: An Evidence Review for the U.S. Preventive Services Task Force. Evidence Synthesis No. 163. AHRQ Publication No. 17-05235-EF-1. Rockville, MD: Agency for Healthcare Research and Quality; 2017.
19. Cournot M, Taraszkiewicz D, Galinier M, et al. Is exercise testing useful to improve the prediction of coronary events in asymptomatic subjects? Eur J Cardiovasc Prev Rehabil. 2006;13(1):37-44.
20. Cournot M, Taraszkiewicz D, Cambou JP, et al. Additional prognostic value of physical examination, exercise testing, and arterial ultrasonography for coronary risk assessment in primary prevention. Am Heart J. 2009;158(5):845-51.
21. Chang SM, Nabi F, Xu J, et al. Value of CACS compared with ETT and myocardial perfusion imaging for predicting long-term cardiac outcome in asymptomatic and symptomatic patients at low risk for coronary disease: clinical implications in a multimodality imaging world. JACC Cardiovasc Imaging. 2015;8(2):134-44.
22. Erikssen G, Bodegard J, Bjørnholt JV, Liestøl K, Thelle DS, Erikssen J. Exercise testing of healthy men in a new perspective: from diagnosis to prognosis. Eur Heart J. 2004;25(11):978-86.
23. Aktas MK, Ozduran V, Pothier CE, Lang R, Lauer MS. Global risk scores and exercise testing for predicting all-cause mortality in a preventive medicine program. JAMA. 2004;292(12):1462-8.
24. Denes P, Larson JC, Lloyd-Jones DM, Prineas RJ, Greenland P. Major and minor ECG abnormalities in asymptomatic women and risk of cardiovascular events and mortality. JAMA. 2007;297(9):978-85.
25. Badheka AO, Patel N, Tuliani TA, et al. Electrocardiographic abnormalities and reclassification of cardiovascular risk: insights from NHANES-III. Am J Med. 2013;126(4):319-26.e2.
26. Auer R, Bauer DC, Marques-Vidal P, et al; Health ABC Study. Association of major and minor ECG abnormalities with coronary heart disease events. JAMA. 2012;307(14):1497-505.
27. Badheka AO, Patel NJ, Grover PM, et al. ST-T wave abnormality in lead aVR and reclassification of cardiovascular risk (from the National Health and Nutrition Examination Survey-III). Am J Cardiol. 2013;112(6):805-10.
28. Shah AJ, Vaccarino V, Janssens AC, et al. An electrocardiogram-based risk equation for incident cardiovascular disease from the National Health and Nutrition Examination Survey. JAMA Cardiol. 2016;1(7):779-86.
29. Myers J, Arena R, Franklin B, et al; American Heart Association Committee on Exercise, Cardiac Rehabilitation, and Prevention of the Council on Clinical Cardiology, the Council on Nutrition, Physical Activity, and Metabolism, and the Council on Cardiovascular Nursing. Recommendations for clinical exercise laboratories: a scientific statement from the American Heart Association. Circulation. 2009;119(24):3144-61.
30. American College of Sports Medicine. ACSM's Guidelines for Exercise Testing and Prescription. 10th ed. Philadelphia: Wolters Kluwer; 2017.
31. Chou R; High Value Care Task Force of the American College of Physicians. Cardiac screening with electrocardiography, stress echocardiography, or myocardial perfusion imaging: advice for high-value care from the American College of Physicians. Ann Intern Med. 2015;162(6):438-47.
32. Wolk MJ, Bailey SR, Doherty JU, et al; American College of Cardiology Foundation Appropriate Use Criteria Task Force. ACCF/AHA/ASE/ASNC/HFSA/HRS/SCAI/SCCT/SCMR/STS 2013 multimodality appropriate use criteria for the detection and risk assessment of stable ischemic heart disease: a report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, American Heart Association, American Society of Echocardiography, American Society of Nuclear Cardiology, Heart Failure Society of America, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, and Society of Thoracic Surgeons. J Am Coll Cardiol. 2014;63(4):380-406.
33. American Academy of Family Physicians. Clinical Preventive Service Recommendation: Coronary Heart Disease, Adults. http://www.aafp.org/patient-care/clinical-recommendations/all/cvd.html#cvd-2. 2012. Accessed December 7, 2017.
34. Lim L, Haq N, Mahmood S, Hoeksema L; ACPM Prevention Practice Committee; American College of Preventive Medicine. Atherosclerotic cardiovascular disease screening in adults: American College of Preventive Medicine position statement on preventive practice. Am J Prev Med. 2011;40(3):380.e1-10.
Internet Citation: Draft Recommendation Statement: Cardiovascular Disease Risk: Screening With Electrocardiography. U.S. Preventive Services Task Force. January 2018.