Discussion in 'General Residency Issues' started by bulldog, Aug 18, 2007.
What's the difference between these days and why would u choose one over the other? thanks.
In a traditional "stress" test, the patient's heart is exercise stressed, usually by having the patient work on a treadmill to evaluate the heart when it is working its hardest.
Some patients cannot tolerate the exercise stress and are instead given medication to simulate the stress; most commonly this is dobutamine.
The stress thal is a combination of the exercise or dobutamine stress test followed by the injection of a nuclear tracer (thallium-99) to measure cardiac blood flow. The patient reaches the point of max stress (either exercise ro dobuta induced), gets the thallium injection and has images taken with the gamma camera to show perfusion. Areas which show no thallium perfusion are presumably dead scar tissue, likely from a prior MI.
You should be able to find a chart somewhere that explains what tests you should use in what situations.
Beyond that, in our hospital the radiologists read all nuclear imaging and the cardiologists read all echos. So the radiologists overcalled stuff and the cardiologists undercalled.... which test we chose depended on whether we wanted the patient to come back positive and stay, or come back negative and go home. Most of the time we wanted the patient to go home.
where's this chart? so what do u mean come back positive and stay?
you are a moron
go to www.utdol.com at your hospital and type in "stress test."
your question is kind of confusing.
stress test is bascially a test that aims at finding inducible ischemia.
there are basically two ways of genrating stress to the heart:
1. exercise and
2 pharmacological (including dobutamine-works by increasing HR and SV, adenosine and dipyridamole works by dilation of epicardic arteries and steal blood flow )
Endpoint markers of inducible ischemia can include:
2. EKG changes: in ST-T and ventricular arrhythmyas
3. ECHO looking for wall motion abnormalities.
4. perfusion imaging ( nuclear medicine test that uses isotopes to evaluate perfusion and are either thalium or sestamibi technesium)
Basically they can be combined anyway you want but most commonly is echo-dobutamine and dypiridamole-thalium.
Best test depends on clinical scenario, for example adenosine and dipyridamole are usually not recommended in asthmatic patients, EKG not useful with LBBB, also dobutamine with LBBB not a good idea because increase HR can potentialy induce false positive for asynchronous septal movement).
hope this helps,
It's about 88% sensitive (it'll pick up disease 88% of the time when it's truly present) and 77% specific (it'll be negative about 23% of the time when disease really isn't present). What you really want to know is the 'positive predictive value' and 'negative predictive value', which is the chance that a positive or negative result is tue - unfortunately, that depends on how likely the patient is to have disease.
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