CV Diagnostics 2 Flashcards
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 MI
- unstable angina
- acute systemic illness
- severe aortic stenosis
- CHF exacerabation
- sever HTN
Excerise EKG
- 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
Exercise EKG
- 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
- prognosis
- 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.
Exercise EKG
-criteria for a positive test
Criteria:
-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
- evaluate prognosis
Myocardial perfusion scintigraphy w/ SPECT
- aka
- what is SPECT?
- what is the purpose
- procedure
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
- Procedure:
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
Stress Echocardiography
- procedure
- purpose
- images are of which heart chamber?
- what is this evaluating about this chamber?
- what does this test tell you?
procedure:
- 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.
MUGA Scan
- 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?
-MUGA scan
Cardiac CT
- 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
Cardiac MRI
-purpose
-perfusion images post pharmacologic stress can be obtains (dobutamine or adenosine)
