Q99) A 65 y/o man with presents to your office with complaints of exertional chest pain for the past 4 weeks. The chest pain is usually left sided, occurs on walking about three blocks and goes away with rest. He has developed a habit of taking rest when the chest pain comes and he did not think it needed medical attention until his friend told him yesterday that it might be a symptom of heart disease. He is concerned and requests your recommendation. He denies any chest pain now. He also reports no change in quality or intensity of his chest pain. His past medical history is significant for pacemaker insertion for a symptomatic second degree heart block, Hypertension, and Smoking . His medications include lisinopril, atenolol and hydrochlorthiazide. Physical examination is benign. An EKG is obtained which reveals pacemaker rhythm with secondary ST-T changes. The next best step in establishing the diagnosis and prognosis in this patient is :
A) 2 D -Echocadiogram
B) Exercise Stress Test ( Treadmill Stress Test)
C) Dobutamine Stress Echocardiogram
D) Persantin Stress Test
E) Cardiac Catheterization
Archer USMLE Step 3 Blog 
B
Answer = E
The patient has multiple risk factors such as previous arrhytmia, Hypertension and smoking, 65 years old. and EKG changes. He needs to go for cardiac angiogram to check disease extension and decide management.
D
cause atenolol
answer should be exercise thallium or exercise echo.
when u cannot read the ecg due to baseline abnormalities like lbbb or pacemaker use then it is exercise thallium or exercise echo.
c is the answer. thinking patient cannot exercise for maximal heart rate ,it should be dobutamine echo.
pacemaker use causing baseline abnormality,so 2 best methods of detecting ischemia without EKG are either nuclear isotope uptake thallium or sestamibi,or echocardiographic detection of wall motion abnormalities.
so I dont think answer is d,,, it could be persantine in combination with thallium
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the answer is C ! coz usual stress test is C/I due to ECG baseline abnormalities & the presence of pacemaker so you go either to nuclear stress test ( which isn’t in the choices ) or to dobutamine echo to visualize wall motion abnormalities , if the test was positive you go to angio !
c, but for sure he has an ischemic condition that will end in cardiac cath E
Yes, pre-test probability is very high here ( Typical Angina, risk factors). The reason stress test is recommended even when high pre-test probability is present is because stress test provides both diagnostic and prognostic information prior to cath and it will also determine the extent of benefit the patient may achieve from re-vascularization.
But one should realize that when pre-test probability is very high, a negative test could mean a false positive – so, a negative stress test in a case like this should be considered as false negative and eventually, he will still need Cath.
Once you know Stress test is the first step, next step is to determine the type of stress test. Why did you choose Dobutamine echo here?
are you suggesting that it is not C?
i thought it would be exercise thallium testing or
stress echo based on pacemaker in question. Without those as a choice, C seemed like a reasonable choice.
because of the paced rhythm / LBBB giving poor interpretation of the stress ecg, reasonable to go for stress echo..
http://imaging.onlinejacc.org/article.aspx?articleid=1109406
left bundle branch block should not undergo dobutamine stress testing.because EKG interpretation will be totally inaccurate = giving false positive or negative results
the answer is D persantin stress test, this patient has symptoms of CAD- angina. He also has a pacemaker for 2nd degree heart block with pacemaker rhythm and secondary ST-T changes, and he is taking a B-blocker, he is NOT a candidate for exercise stress test as the EKG changes will not be identified accurately, also with a b blocker it will be more difficult for the patient to reach 85% heart rate according to bruce protocol. he needs to have the next appropriate test which is nuclear imaging with persantine which shows areas of reversible ischaemia by coronary steal, during stress ( with exercise) those arteries that are occluded are already maximally dilated and so will not dilate further with persantine, but health arteries will and draw blood to the healthy arteries causing ischaemia from diseases arteries, this is vasodilatory stress test
So, answer is D according to Usmlegalaxy?