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Diagnostic Testing: Difference between revisions
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The stress response is induced by exercise or drug stimulation. Cardiac stress tests compare the coronary circulation while the patient is at rest with the same patient's circulation observed during maximum physical exertion, showing any abnormal blood flow to the heart's muscle tissue (the myocardium). The results can be interpreted as a reflection on the general physical condition of the test patient. This test can be used to diagnose ischemic heart disease, and for patient prognosis after a heart attack (myocardial infarction). | The stress response is induced by exercise or drug stimulation. Cardiac stress tests compare the coronary circulation while the patient is at rest with the same patient's circulation observed during maximum physical exertion, showing any abnormal blood flow to the heart's muscle tissue (the myocardium). The results can be interpreted as a reflection on the general physical condition of the test patient. This test can be used to diagnose ischemic heart disease, and for patient prognosis after a heart attack (myocardial infarction). | ||
The cardiac stress test is done with heart stimulation, either by exercise on a treadmill, pedalling a stationary exercise bicycle ergometer | The cardiac stress test is done with heart stimulation, either by exercise on a treadmill, pedalling a stationary exercise bicycle ergometer<cite>One</cite> or with intravenous pharmacological stimulation, with the patient connected to an electrocardiogram (or ECG). People who cannot use their legs may exercise with a bicycle-like crank that they turn with their arms.<cite>Two</cite> | ||
The level of mechanical stress is progressively increased by adjusting the difficulty (steepness of the slope) and speed. The test administrator or attending physician examines the symptoms and blood pressure response. With use of ECG, the test is most commonly called a cardiac stress test, but is known by other names, such as exercise testing, stress testing treadmills, exercise tolerance test, stress test or stress test ECG. | The level of mechanical stress is progressively increased by adjusting the difficulty (steepness of the slope) and speed. The test administrator or attending physician examines the symptoms and blood pressure response. With use of ECG, the test is most commonly called a cardiac stress test, but is known by other names, such as exercise testing, stress testing treadmills, exercise tolerance test, stress test or stress test ECG. | ||
==Stress echocardiography== | ==Stress echocardiography== | ||
A stress test may be accompanied by echocardiography. | A stress test may be accompanied by echocardiography.<cite>One</cite> The echocardiography is performed both before and after the exercise so that structural differences can be compared. | ||
==Nuclear stress test== | ==Nuclear stress test== | ||
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==Diagnostic value== | ==Diagnostic value== | ||
The common approach for stress testing by American College of Cardiology and American Heart Association indicates the following: | The common approach for stress testing by American College of Cardiology and American Heart Association indicates the following:<cite>Two</cite> | ||
*'''Treadmill test:''' sensitivity 73-90%, specificity 50-74% (Modified Bruce Protocol) | *'''Treadmill test:''' sensitivity 73-90%, specificity 50-74% (Modified Bruce Protocol) | ||
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==Contraindications== | ==Contraindications== | ||
Stress cardiac imaging is not recommended for asymptomatic, low-risk patients as part of their routine care. | Stress cardiac imaging is not recommended for asymptomatic, low-risk patients as part of their routine care.<cite>Three</cite> Some estimates show that such screening accounts for 45% of cardiac stress imaging, and evidence does not show that this results in better outcomes for patients.<cite>Three</cite> Unless high-risk markers are present, such as diabetes in patients aged over 40, peripheral arterial disease; or a risk of coronary heart disease greater than 2 percent yearly, most health societies do not recommend the test as a routine procedure.<cite>Three</cite><cite>Four</cite><cite>Five</cite><cite>Six</cite> | ||
Absolute contraindications to cardiac stress test include: | Absolute contraindications to cardiac stress test include: | ||
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*Severe symptomatic aortic stenosis, aortic dissection, pulmonary embolism, and pericarditis | *Severe symptomatic aortic stenosis, aortic dissection, pulmonary embolism, and pericarditis | ||
*Multivessel coronary artery diseases that have a high risk of producing an acute myocardial infarction | *Multivessel coronary artery diseases that have a high risk of producing an acute myocardial infarction | ||
*Decompensated or inadequately controlled congestive heart failure | *Decompensated or inadequately controlled congestive heart failure<cite>Seven</cite> | ||
*Uncontrolled hypertension (blood pressure>200/110mm Hg) | *Uncontrolled hypertension (blood pressure>200/110mm Hg)<cite>Seven</cite> | ||
*Severe pulmonary hypertension | *Severe pulmonary hypertension<cite>Seven</cite> | ||
*Acute aortic dissection | *Acute aortic dissection<cite>Seven</cite> | ||
*Acutely ill for any reason | *Acutely ill for any reason<cite>Seven</cite> | ||
==Adverse effects== | ==Adverse effects== | ||
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The choice of pharmacologic stress agents used in the test depends on factors such as potential drug interactions with other treatments and concomitant diseases. | The choice of pharmacologic stress agents used in the test depends on factors such as potential drug interactions with other treatments and concomitant diseases. | ||
Pharmacologic agents such as Adenosine, Lexiscan (Regadenoson), or dipyridamole is generally used when a patient cannot achieve adequate work level with treadmill exercise, or has poorly controlled hypertension or left bundle branch block. However, an exercise stress test may provide more information about exercise tolerance than a pharmacologic stress test. | Pharmacologic agents such as Adenosine, Lexiscan (Regadenoson), or dipyridamole is generally used when a patient cannot achieve adequate work level with treadmill exercise, or has poorly controlled hypertension or left bundle branch block. However, an exercise stress test may provide more information about exercise tolerance than a pharmacologic stress test.<cite>Eight</cite> | ||
Commonly used agents include: | Commonly used agents include: | ||
*Vasodilators acting as adenosine receptor agonists, such as Adenosine itself, and Dipyridamole (brand name "Persantine"), | *Vasodilators acting as adenosine receptor agonists, such as Adenosine itself, and Dipyridamole (brand name "Persantine"),<cite>Nine</cite> which acts indirectly at the receptor. | ||
*Regadenoson (brand name "Lexiscan"), which acts specifically at the Adenosine A2A receptor, thus affecting the heart more than the lung. | *Regadenoson (brand name "Lexiscan"), which acts specifically at the Adenosine A2A receptor, thus affecting the heart more than the lung. | ||
*Dobutamine. The effects of beta-agonists such as dobutamine can be reversed by administering beta-blockers such as propranolol. | *Dobutamine. The effects of beta-agonists such as dobutamine can be reversed by administering beta-blockers such as propranolol. | ||
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==References== | ==References== | ||
<biblio> | |||
#One Rimmerman, Curtis (2009-05-05). The Cleveland Clinic Guide to Heart Attacks. Kaplan Publishing. pp. 113–. ISBN 978-1-4277-9968-5. Retrieved 25 September 2011. | |||
#Two Gibbons, R., Balady, G.; Timothybricker, J., Chaitman, B., Fletcher, G., Froelicher, V., Mark, D., McCallister, B. et al. (2002). "ACC / AHA 2002 guideline update for exercise testing: summary article A report of the American College of Cardiology / American Heart Association Task Force on Practice Guidelines,Journal of the American College of Cardiology | |||
#Three American College of Cardiology, "Five Things Physicians and Patients Should Question", Choosing Wisely: an initiative of the ABIM Foundation (American College of Cardiology), retrieved August 17 2012 | |||
#Four Taylor, A. J.; Cerqueira, M.; Hodgson, J. M. .; Mark, D.; Min, J.; O'Gara, P.; Rubin, G. D.; American College of Cardiology Foundation Appropriate Use Criteria Task Force et al. (2010). "ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography". Journal of the American College of Cardiology 56 (22): 1864–1894. doi:10.1016/j.jacc.2010.07.005. PMID 21087721. edit | |||
#Five Douglas, P. S.; Garcia, M. J.; Haines, D. E.; Lai, W. W.; Manning, W. J.; Patel, A. R.; Picard, M. H.; Polk, D. M. et al. (2011). "ACCF/ASE/AHA/ASNC/HFSA/HRS/SCAI/SCCM/SCCT/SCMR 2011 Appropriate Use Criteria for Echocardiography". Journal of the American College of Cardiology 57 (9): 1126–1166. doi:10.1016/j.jacc.2010.11.002. PMID 21349406. edit | |||
#Six Hendel, R. C.; Abbott, B. G.; Bateman, T. M.; Blankstein, R.; Calnon, D. A.; Leppo, J. A.; Maddahi, J.; Schumaecker, M. M. et al. (2010). "The role of radionuclide myocardial perfusion imaging for asymptomatic individuals". Journal of Nuclear Cardiology 18 (1): 3–15. doi:10.1007/s12350-010-9320-5. PMID 21181519. edit | |||
#Seven Henzlova, Milena; Cerqueira, Hansen, Taillefer, Yao (2009). "Stress Protocols and Tracers". Journal of Nuclear Cardiology. doi:10.1007/s12350-009-9062-4. | |||
#Eight Weissman, Neil J.; Adelmann, Gabriel A. (2004). Cardiac imaging secrets. Elsevier Health Sciences. pp. 126–. ISBN 978-1-56053-515-7. Retrieved 25 September 2011. | |||
#Nine Nicholls, Stephen J.; Worthley, Stephen (2011-01). Cardiovascular Imaging for Clinical Practice. Jones & Bartlett Learning. pp. 198–. ISBN 978-0-7637-5622-2. Retrieved 25 September 2011. | |||
</biblio> | |||