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Encyclopedia > Cardiac stress test

A cardiac stress test is a medical test performed to evaluate relative arterial blood flow increases to the left ventricular heart muscle during exercise, as compared to resting blood flow rates (i.e. myocardial perfusion reserve), and some indication of overall physical fitness. Stress test abnormalities reflect major imbalances of blood flow, flow that does not increase in a region of left ventricular muscle nearly as much as in other regions. Stress testing can detect areas of myocardium in which blood flow is limited by medium to high grade stenosis of the larger coronary arteries; too high grade for the coronary microcirculation to adequately compensate. Such stenoses are the usual basis for stable or reproducible exercise related angina and reflect advanced arterial disease, though not the basis for most heart attacks. A medical test is any kind of diagnostic procedure performed for health reasons. ... Section of an artery An arterial road is a class of highway. ... Blood flow is the flow of blood in the cardiovascular system. ... The heart and lungs (from an older edition of Grays Anatomy) The heart (Latin cor) is a hollow, muscular organ that pumps blood through the blood vessels by repeated, rhythmic contractions. ... A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure. ... Atherosclerosis is a disease affecting arterial blood vessels (as well as veins that have been surgically moved to function as arteries). ... A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ...


Generally, stress tests are effective at detecting myocardial ischemia due to medium or high grade epicardial arterial stenosis and previous heart attacks (i.e. regions in which blood flow is low enough that cell death has occurred and has been replaced by fibrous tissue).


The tests are not capable of detecting the presence/absence of the atheroma lesions of atherosclerosis, especially "vulnerable plaques". Thus they usually miss disease locations, about 20% stenosis average, which most commonly result in future heart attack events (see atheroma for a better understanding of this issue). This is the primary, long recognized basis for individuals having normal stress tests, followed a short time later by "surprise" heart attacks. Also, the test is not designed to evaluate the presence or influences of emotional stresses, even though these probably play a role in heart attacks. An atheroma (plural: atheromata) is an abnormal fatty deposit which develops within the walls of arteries over time. ... A vulnerable plaque is an atheromatous plaque which is particularly prone to produce sudden major problems, such as a heart attack or stroke. ... A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ... An atheroma (plural: atheromata) is an abnormal fatty deposit which develops within the walls of arteries over time. ... A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ... Emotions are essentially impulses that move an organism to action, originating automatic reaction behavior which has been perfected through evolution as a survival need. ...

Contents


Test Overview

The patient either walks on a treadmill or is given IV medications to "simulate exercise" while connected to an EKG machine, usually the standard 10 connections used to record a 12 lead EKG, and blood pressure response is repeatedly checked. Using EKG and blood pressure monitoring alone, the test is variously called a cardiac stress test, exercise stress test, exercise treadmill test or exercise EKG test. If radioactive isotopes are also used, then it is usually called a nuclear thallium (thallium-201) or Cardiolite (Technetium Tc99m Sestamibi) stress test (see gamma camera) or a Rubidium (Rubidium, RB-82) PET stress test. None of the mentioned methods provide precise quantitative measurements of blood flow or blood flow changes; quantitatively balanced reductions in blood flow are not detected as abnormalities. It is a well known that nuclear stress tests with sestamibi, thallium can in many instances underestimate the extent of ischemia in patients with multi-vessel coronary disease (i.e. "balanced ischemia"). This "balanced ischemia" may only be seen as a slight dilatation of the LV cavity at stress (i.e. transient ischemic dilation or TID) and not as a frank perfusion defect on sestamibi or thallium scans. Quantitative myocardial perfusion reserve can be determined with O-15 water or N-13 ammonia PET after pharmacologically induced stress with adenosine or dipyridamole, thus allowing for detection of global reduction of blood flow, but this is rarely used clinically because of very limited availability, increased cost and complexity. ECG may also refer to the East Coast Greenway Lead II An Electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical voltage in the heart in the form of a continuous strip graph. ... ECG may also refer to the East Coast Greenway Lead II An Electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical voltage in the heart in the form of a continuous strip graph. ... Blood pressure is the pressure exerted by the blood on the walls of the blood vessels. ... ECG may also refer to the East Coast Greenway Lead II An Electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical voltage in the heart in the form of a continuous strip graph. ... A radionuclide is an atom with an unstable nucleus. ... General Name, Symbol, Number thallium, Tl, 81 Chemical series poor metals Group, Period, Block 13, 6, p Appearance silvery white Atomic mass 204. ... Cardiolite&reg is the brand name of sestamibi, a radiopharmaceutical used in nuclear medicine imaging. ... A gamma camera is an imaging device, most commonly used as a medical imaging device nuclear medicine. ... General Name, Symbol, Number rubidium, Rb, 37 Chemical series alkali metals Group, Period, Block 1, 5, s Appearance silvery white Atomic mass 85. ... Pets and humans often contribute toward the happiness of the other in a pet relationship. ...


Advances in magnetic resonance imaging MRI have expanded the choice of modalities available for cardiac stress testing. MRI has superior spatial resolution (on the order of around 1.5 mm for cine imaging and 2.5 mm for perfusion imaging), and temporal resolution (around 40 ms for cine imaging), compared with that of a nuclear or PET stress test (spatial resolution of around 9mm for nuclear and 6mm for PET). The increased spatial resolution allows for more sensitive detection of ischemia, which initially starts at the thin subendocardial layer, due to stenotic epicardial supply vessels. First-pass stress perfusion cardiac MR imaging is performed using a rapid bolus injection of gadolinium based contrast and rapidly obtaining T1 weighted images of the myocardium at every R-R interval after pharmacologic stress induced with adenosine. The stress and resting first-pass perfusion MRI data can then be analyzed using a convolution model (such as the Marquard-Levenberg least-squares algorithm) to determine the quantitative global myocardial perfusion reserve (Michael Jerosch-Herold). Delayed hyper-enhancement imaging can be done after 10-15 minutes of contrast injection to evaluate for regions of infarction or fibrosis which has increased signal due to the slower washout of contrast from these areas (Thomson LE). Stress cardiac MRI perfusion testing thus is sensitive enough to detect subtle ischemia and myocardial infarctions even if they are limited only to the subendocardial level. The major problem again is that they still do not detect the "vulnerable plaques" which is the major cause of most heart attacks. The mri are a fictional alien species in the Faded Sun Trilogy of C.J. Cherryh. ...


Purpose

The stress test is used to check both overall physical exercise capacity and is generally able to detect medium to high grade stenosis of the coronary arteries supplying the cardiac muscle. Heart rate is the most important variable for stress testing because heart muscle contraction blocks heart muscle capillary blood flow during each heart beat and the time for blood flow between heart contractions progressively shortens as heart rate increases; e.g. about 40 seconds per minute, at heart rates of about 60 BPM, down to less than 10 seconds per minute, at heart rates in the 180 BPM range. A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure. ... The coronary circulation consists of the blood vessels that supply blood to, and remove blood from, the heart. ... Cardiac muscle is a type of striated muscle found within the heart. ... Capillaries are the smallest of a bodys blood vessels, measuring 5-10 μm. ...


The American Heart Association recommends EKG treadmill testing as the first choice for patients with medium risks of coronary heart disease based on the risk factors of smoking, family history of coronary stenosis, hypertension, diabetes and high blood cholesterol.


Perfusion (Cardiolite) stress testing is approriate for select patients, especially those with abnormal resting EKG. More severe stenosis, probably greater than 70%, can produce both abnormalities in both EKG waveforms and wall motion on stress echocardiographic testing. Such high grade narrowings are typically the primary cuplrit responsible for those angina episodes which reproducibly occur at a given level of exercise. However, most heart attacks result from rupture of atheroma lesions associated with only mild narrowing, 20% on average by IVUS clinical studies, thus the tests do not work well for detecting "vulnerable plaques" which are responsible for most heart attacks. Like all tests, stress testing has both falsely positive and falsely negative problems when results are compared with other clinical test results. ECG may also refer to the East Coast Greenway Lead II An Electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical voltage in the heart in the form of a continuous strip graph. ... An echocardiogram. ... A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure. ... A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ... An atheroma (plural: atheromata) is an abnormal fatty deposit which develops within the walls of arteries over time. ... A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure. ... Intravascular ultrasound (IVUS) is an medical imaging methodology using (a) specially designed long thin complex manufactured catheters attached to (b) computerized ultrasound equipment. ... A false positive, also called false alarm, exists when a test reports, incorrectly, that it has found a signal where none exists in reality. ... A false negative, also called a miss, exists when a test reports, incorrectly, that a signal was not detected when, in fact, was present. ...


Angiogram and intracoronary ultrasound, preferably in a hosptial capable of Percutaneous Coronary Intervention with stenting provides even greater information at the cost of increased complications.


Variations

Sometimes radioactive isotopes are injected intravenously at approximately one minute prior to the end of exercise. This protocol would be called a nuclear cardiac stress test. Either a gamma camera or PET imaging machine is used to create several 2 dimensional pictures, from different angles, of the radioactive particle decay emissions emanating from the radioactive isotopes which have been absorbed by the heart muscle cells from the blood after the intravenous injection. These images are compared with resting radioactive isotope emission distribution images for differences. Variations of nuclear cardiac stress tests include a thallium, technetium or rubidium (only used for PET machines) stress test, depending on the radioactive atomic element used. Cardiac stress imaging can also be performed with MRI. A radionuclide is an atom with an unstable nucleus. ... A gamma camera is an imaging device, most commonly used as a medical imaging device nuclear medicine. ... Pets and humans often contribute toward the happiness of the other in a pet relationship. ... Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ... A radionuclide is an atom with an unstable nucleus. ... An intravenous drip in a hospital Intravenous therapy or IV therapy is the administration of liquid substances directly into a vein. ... A radionuclide is an atom with an unstable nucleus. ... General Name, Symbol, Number thallium, Tl, 81 Chemical series poor metals Group, Period, Block 13, 6, p Appearance silvery white Atomic mass 204. ... General Name, Symbol, Number technetium, Tc, 43 Chemical series transition metals Group, Period, Block 7, 5, d Appearance silvery gray metal Atomic mass (98) g/mol Electron configuration [Kr] 4d5 5s2 Electrons per shell 2, 8, 18, 13, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number rubidium, Rb, 37 Chemical series alkali metals Group, Period, Block 1, 5, s Appearance silvery white Atomic mass 85. ... Pets and humans often contribute toward the happiness of the other in a pet relationship. ... Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ...


Sometimes heart muscle size, contraction and wall motion is physically evaluated before and immediately after the exercise phase using an echocardiography machine. This protocol would be called a echocardiographic cardiac stress test. The heart and lungs (from an older edition of Grays Anatomy) The heart (Latin cor) is a hollow, muscular organ that pumps blood through the blood vessels by repeated, rhythmic contractions. ... An echocardiogram. ... An echocardiogram. ...


Contraction and wall motion can also be evaluated with MRI after stress testing with dobutamine which stimulates faster heart rates and more intense contraction. As noted, the higher spatial resolution of MRI allows for detection of more subtle wall motion abnormalities compared to stress echo. This is however not as sensitive as first-pass perfusion imaging for detection of ischemia. As the result, dobutamine stress cardiac MRI is usually performed only if the patient has some contraindications (such as asthma) to adenosine.


Sometimes, if an individual is unable to perform enough physical exercise walking up an incline, then exercise is simulated using medications to stimulate faster heart rate, more intense contraction and/or peripheral arteriole vasodilatation. The heart and lungs (from an older edition of Grays Anatomy) The heart (Latin cor) is a hollow, muscular organ that pumps blood through the blood vessels by repeated, rhythmic contractions. ... An arteriole is a blood vessel that extends and branches out from an artery and leads to capillaries. ... The blood vessels are part of the circulatory system and function to transport blood throughout the body. ...


Diagnostic Value

Unfortunately, the value of such a test is limited, especially for asymptomatic individuals. According to United States data, 2004, for about 65% of men and 47% of women, the first symptom of cardiovascular disease is heart attack or sudden death (death within one hour of symptom onset.) The term symptom (from the Greek syn = con/plus and pipto = fall, together meaning co-exist) has two similar meanings in the context of physical and mental health: A symptom may loosely be said to be a physical condition which shows that one has a particular illness or disorder (see... Cardiac Arrest (1974-1980) is a Horror-Comedy-Crime-Thriller-Drama-Movie with Robert Behling, Fred Ward and Max Gail. ...


Stress testing, even if done in time, will detect only some of these people before symptoms, debility or death. Stress testing methods, though more effective than a resting EKG, only detect medium to high grade flow limitations; this assuming the testing is fully and aggressively performed. However, most acute artery flow disrupting events leading to heart attacks are due to rupture of "vulnerable plaques". Most of the "vulnerable plaques" cause less than 40% lumen narrowing, a degree of stenosis too small for most stress testing methods to detect. In anatomy, the lumen is the cavity or channel within a tube or tubular structure, such as the vascular lumen of a blood vessel, along which blood flows. ... A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure. ...


Historically, through the mid-1980s, it was believed that detecting these high grade stenoses was the key to recognizing people who would have heart attacks in the future. However, there was also long-standing experience that some people could exercise all the way to maximum predicted heart rate, have no abnormal symptoms and completely normal stress test results, only to die of a massive heart attack within a few days to weeks. From the 1960s to 1990s, despite the success of stress testing identifying many who were at high risk for heart attack, its failure to correctly identify many others was a conundrum, discussed in medical circles but unexplained. A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ... A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ... A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ...


The high grade stenoses which are detected by stress test methods are often, though not always, responsible for recurring symptoms of angina. Cardiac stress tests do detect some individuals who already have with very advanced coronary arterial disease and stenosis, some of whom did not recognize that they had advanced disease. However, stress test results (especially stress perfusion cardiac MRI which can detected subtle diffuse subendocardial decreased perfusion due to microvascular disease) are also sometimes abnormal in some people who do not have high grade narrowings of their coronary arteries as visualized by coronary angiography, which provides more accurate information and partial visualization of the coronary artery lumens. This was long viewed as a false positive result, with some of these individuals diagnosed as having Syndrome X, i.e meaning clear recurring signs of angina, though with smooth open coronary artery lumens on coronary angiography. The actual underlying issues responsible for this apparent conundrum are now better understood, see atheroma and microvascular disease. A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure. ... angina tonsillaris see tonsillitis. ... The coronary circulation consists of the blood vessels that supply blood to, and remove blood from, the heart. ... A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure. ... A coronary catheterization is a minimally invasive procedure to access the coronary circulation and blood filled chambers of the heart using a catheter. ... The coronary circulation consists of the blood vessels that supply blood to, and remove blood from, the heart. ... In anatomy, the lumen is the cavity or channel within a tube or tubular structure, such as the vascular lumen of a blood vessel, along which blood flows. ... A false positive, also called false alarm, exists when a test reports, incorrectly, that it has found a signal where none exists in reality. ... (Cardiac) syndrome X is angina(Chest Pain) with signs associated with decreased blood flow to heart tissue but with norman Coronary arteries. ... The coronary circulation consists of the blood vessels that supply blood to, and remove blood from, the heart. ... A coronary catheterization is a minimally invasive procedure to access the coronary circulation and blood filled chambers of the heart using a catheter. ... An atheroma (plural: atheromata) is an abnormal fatty deposit which develops within the walls of arteries over time. ... Microvascular disease is a disease of any small blood vessels in the body. ...


In the 1950s, heart attacks were commonly attributed to coronary thrombosis, a clot closure of a coronary artery, based on post mortem examination findings. In the late 1950s to early 1960s, this concept became replaced by the concept of stenosis based on the angiographic view of the lumens of the coronary arteries. In turn the angiographic view led to promotion of cardiac stress testing to detect stenoses, i.e. the severe ones more commonly present in people experiencing recurrent angina with physical exertion. Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. ... The coronary circulation consists of the blood vessels that supply blood to, and remove blood from, the heart. ... A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure. ... A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure. ... angina tonsillaris see tonsillitis. ...


By the early to mid-1990s, it became more widely recognized that rupture of more rapidly evolving and unstable atheroma, hidden within the walls of the coronary arteries, called "vulnerable plaques", even though they often produce little or no stenosis of the coronary lumen, is the primary event which produces most heart attacks; thus back to the coronary thrombosis view, though with more sophistication of understanding some of the complexities. Two clinical trials published in the late 1990's, focusing on the relation between plaque structure, lumen stenosis and myocardial infarction, in which each individuals coronary anatomy was tracked with both angiography and IVUS found that 75% or greater stenotic areas were responsible for only about 14% of heart attacks. The typical heart attack occurred at an artery location with extensive, eccentric plaque within the wall but a luminal stenosis of only 20%. This finding added further evidence to the importance of the concept of vulnerable plaques. The detection of these vulnerable plaques using high resolution CT, MRI, IVUS, OCT (Optical Coherence Tomography), and molecular imaging is currently hotly researched. For CT, as of 2005, 64-slice multidetector machines are providing the best artery and lumen images, yet still do not clearly reveal which plaques are vulnerable. It is hope that perhaps with better resolution and ability to characterize the content of the plaques that an imaging modality may in the future be able to indicate which plaques is "vulnerable" as it is clear that detecting stenosis itself, however subtle, is not enough. An atheroma (plural: atheromata) is an abnormal fatty deposit which develops within the walls of arteries over time. ... A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure. ... A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ... Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. ... A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ... Angiography or arteriography is a medical imaging technique in which an X-ray picture is taken to visualize the inner opening of blood filled structures, including arteries, veins and the heart chambers. ... Intravascular ultrasound (IVUS) is an medical imaging methodology using (a) specially designed long thin complex manufactured catheters attached to (b) computerized ultrasound equipment. ...


Unfortunately, cardiac stress tests are only capable of detecting medium to high grade limitations of blood flow to the left ventricular heart muscle which may produce recurring angina, not the atheroma which produce heart attacks. Stress test methods do not evaluate blood flow to non-left-ventricle heart muscle. Thus stress test results are often falsely negative for many people, in terms of predicting who is at high risk for myocardial infarction due to atheroma or ruptured "vulnerable plaques". angina tonsillaris see tonsillitis. ... An atheroma (plural: atheromata) is an abnormal fatty deposit which develops within the walls of arteries over time. ... A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ... A false negative, also called a miss, exists when a test reports, incorrectly, that a signal was not detected when, in fact, was present. ... A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ...


It has become clear that stress testing recognizes most people at risk for heart attacks too late, unfortunately only after the disease and symptoms of the disease have developed. By the time, a majority of people would already have at least medium stenosis of coronary vessels with development of atheroma or have already had heart attacks or died. It is hoped that research in higher resolution imaging techniques will allow for earlier detection and characterization of subtle atheroma and to initiate lifestyle changes and optimal medical therapy in "vulnerable patients" before they develop symptoms. A myocardial infarction occurs when an atherosclerotic plaque slowly builds up in the inner lining of a coronary artery and then suddenly ruptures, totally occluding the artery and preventing blood flow downstream. ...


Risks

Stress tests using radiological agents confer a definite (albeit low) long term risk of cancer, but patients undergoing such examinations often receive little or inaccurate information about these risks. For comparison, the annual background radiation per annum a person receives is approximately 3 mSv. A chest xray is approximately 0.1 mSv. A coronary angiogram (cardiac catheterization) has a effective dose of 3-20 mSv (depending on operator skill, type of intervention, etc). A routine chest helical MDCT is around 5-7 mSv. A cardiac CT (with retrospective EKG gating) is around 8-13 mSv (Morin). A sestamibi scan is approximately 12 mSv. A thallium scan is approximately 25 mSv. A thallium scan corresponds the dose of 250 chest x rays, or an extra cancer risk of about 1 in 16000 exposed patients (A. de González). The lifetime risk of fatal cancer development is 4%/Sv or 0.004%/mSv or about 0.1% for a thallium scan. Therefore, frequent usage of these tests has to balance the benefits against the risks of radiation. General Name, Symbol, Number thallium, Tl, 81 Chemical series poor metals Group, Period, Block 13, 6, p Appearance silvery white Atomic mass 204. ...


Another major risk of stress testing, whether by exercise or pharmacological agents, include inducing heart attacks, especially in patients with severe multi vessel coronary disease. This risk is, however, sustantially much lower than the rate (about 1%) of major complications such as inducing heart attacks, stroke, peripheral artery clot and embolism for cardiac catheterization.



Absolute contraindications to cardiac stress testing include acute MI within 48 hrs, unstable angina not yet stablized with medical therapy, uncontrolled arrythmia which may have significant hemodynamic responses (for example ventricular tachicardia), symptomatic severe aortic stenosis, aortic dissection, pulmonary embolism, pericarditis.


The type of pharmacologic stress agents to be used such as dobutamine, adenosine (and dipyridamole) depends on factors such as concurrent medications and diseases. Dobutamine is usually used when patient has asthma or severe COPD, use theophylline, or has taken coffee or chocolate (anything with caffeine), or has 2nd or 3rd degree AV block. Adenosine (and dipyridamole) is generally used when patient has poorly controlled hypertension, glaucoma, or has left bundle branch block (it is well known that patients with LBBB can have false positive septal ischemia if dobutamine is used as a pharmacologic agent in nuclear stress test).


Major side effects from cardiac stress testing include palpitation, chest pain, shortness of breath, headache, nausea, fatigue. Adenosine and dipyridamole can cause mild hypotension. Hypotension caused by exercise stress testing or dobutamine is almost always abnormal and concerning for severe coronary disease.


See also

An atheroma (plural: atheromata) is an abnormal fatty deposit which develops within the walls of arteries over time. ... The coronary circulation consists of the blood vessels that supply blood to, and remove blood from, the heart. ... The diagnostic tests in cardiology are methods of identifying heart conditions associated with healthy vs. ...

Reference

Michael Jerosch-Herold (2004). Analysis of myocardial perfusion MRI. Journal of Magnetic Resonance Imaging 19 (6): 758-770..


Thomson LE (2004). Magnetic resonance imaging for the assessment of myocardial viability. Journal of Magnetic Resonance Imaging 19 (6): 771-788..


A. de González (2004). Risk of cancer from diagnostic X-rays: estimates for the UK and 14 other countries. The Lancet 363 (9406): 345-351..


Morin (2003). Radiation Dose in Computed Tomography of the Heart. Circulation 107: 917-922..


  Results from FactBites:
 
Quinton Products for Advanced Cardiology (238 words)
Cardiac stress testing has been an important diagnostic tool for more than four decades.
Inexpensive and simple to perform, the procedure monitors heart rate, blood pressure and ECG to determine whether induced stress may reveal abnormalities in cardiac function.
We are often acknowledged as a global leader in the cardiac stress testing market.
Cardiac Stress Test (1439 words)
With a "maximal" stress test, the level of exercise is gradually increased until the patient cannot keep up any longer because of fatigue, or until symptoms (chest pain, shortness of breath, or lightheadedness) prevent further exercise, or until changes on the ECC indicate a cardiac problem.
The stress test is useful chiefly in the diagnosis of coronary artery disease.
The accuracy of the stress test in diagnosing coronary artery disease is greatly increased by performing a nuclear perfusion study in conjunction with the stress test.
  More results at FactBites »

 
 

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