Flashcards in CV Diagnostics 2 Deck (14)
Indications for cardiac stress testing?
-establish dx of CAD (symptomatic or asymptomatic with abnormal EKG)
-assessment of prognosis and functional capacity
-assess response to therapy
-evaluate asymptomatic individuals for CAD (firefighers, pilots)
-evaluate for exercised-induced arrhythmias
CI to stress testing
-acute systemic illness
-severe aortic stenosis
-what is this?
-when do you do this?
-EKG while running on a treadmill or bicycle ergometer
-in low risk pts without baseline ST segment abnormalities or when anatomic localization is not necessary exercise EKG is the recommended INITIAL procedure
-what information is obtained?
-if severe ischemia we would expect to see what in blood pressure changes?
-what is the prognosis of a 3minute maximum exercise EKG?
-exercise duration and tolerance
-reproducibility of sx with activity
-heart rate response to exercise
-blood pressure response to exercise
-detection of stress induced arrhythmias
-assess the effectiveness of antianginal memds
-expect to see decrease in blood pressure with exercise.
-very poor prognosis. Generally if they can make it through 6mins they have a good prognosis.
-criteria for a positive test
-1mm horizontal or downsloping ST segment depression measure 80ms after the J point.
(60-80% pt w/ significant CAD will have + test, 10-30% WITHOUT significant disease will also have a + test)
Exercise EKG interpretation: High risk for significant ischemia findings
-BP drop during exercise
-greater than 2mm ST depression
-ST depression that is downsloping
-ST depression or sx at low work loads less than 6min
-ST depression that does not resolve quickly in the recovery phase.
Risks of exercise testing
-1MI or death per 1000 patients
-stress induced arrhythmias
-adverse rxn to pharmacologic stress agent.
Indications for Stress IMAGING
-when resting EKG is abnormal
-confirmation of the results of an exercise EKG when results dont align with clinical impression
-to localize the region of ischemia
-distinguish ischemic from infarcted myocardium
-assessment of revascularization post stent or surgery
Myocardial perfusion scintigraphy w/ SPECT
-what is SPECT?
-what is the purpose
aka: cardiac nuclear perfusion imaging, nuclear stress test
-SPECT: CT technique that takes out some artifact to make it a more reliable test.
-Purpose: to see if myocardial uptake of the radionuclide tracer is proportionate to myocardial perfusion at the time of injection
1. nuclear images taken before and after exercise
2. exercise completed with a treadmill
--if pt unable to exercise pharmacological stress is complete with adenosine or dobutamine
-images are of which heart chamber?
-what is this evaluating about this chamber?
-what does this test tell you?
-echocardiographic images obtain of pt lying supine pre and immediately post exercise.
-exercise completed on treadmill (if cant exercise give dobutamine)
-images are of the left ventricle ONLY!
-evaluation of wall motion abnormalities of the LV. (if there is an area that is lacking blood supply at higher workloads the muscle will not participate during contraction)
-gives you information regarding the presence or absence of ischemia.
-what is this?
-how does it work?
-what does this test evaluate?
-this is Multi-Gated Acquisition Scan
-this works by using radionuclide tracers to image the left ventricle.
-evaluates the wall motion and precisely calculates the EF.
What is the most effective way to measure ejection fraction?
-what are the two types?
-what do each of these tests tell you?
-Types: CT angiography and ELectron Beam CT
-CT Angio: useful in evaluating pts with a low likelihood of significant disease.
--IV contrast given and images of the coronary arteries are obtained
-Electron Beam CT: quantifies coronary artery calcification