USMLE Uworld questions collection (WEEK2)
I) 54 - year - old man is admitted to the hospital due to cough, shortness of
breath, and chest discomfort. He has a known history of coronary artery
disease and underwent coronary artery bypass graft surgery 3 years ago. As
a result of drug therapy, the left ventricular pressure - volume loop changes
from a solid to a dashed line as shown on the graph below.
Which of the following parameters is most likely
to increase as a result of this change?
A. End - diastolic pressure
B. End - systolic volume
C. Stroke volume
D. Ventricular afterload
E. Ventricular preload
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II) The volume and pressure tracings for the left
ventricle of a 34 - year - old male are shown below.
Which of the following points corresponds to aortic
valve opening?
A. A
B. B
C. C
D. D
E. E
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, III) A 46 - year - old patient is undergoing cardiac catheterization. Initially,
the catheter records periodic pressure changes with a maximum of 27
mmHg and minimum of 2 mmHg. The catheter is advanced further, and
then shows periodic pressure changes with a maximum of 26 mmHg and a
minimum of 10 mmHg.
The initial readings were most likely obtained from which of the following
locations?
A. Right atrium
B. Right ventricle
C. Left ventricle
D. Left atrium
E. Pulmonary artery
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IV) Microelectrodes placed into cardiac muscle cells detect a rapid decrease
in cytoplasmic calcium level immediately preceding relaxation.
Which of the following mediates the observed response?
A. Voltage-dependent calcium channels
B. Ryanodine receptors
C. Na+ / Ca+2 exchange mechanism
D. Troponin C
E. Calmodulin
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I) 54 - year - old man is admitted to the hospital due to cough, shortness of
breath, and chest discomfort. He has a known history of coronary artery
disease and underwent coronary artery bypass graft surgery 3 years ago. As
a result of drug therapy, the left ventricular pressure - volume loop changes
from a solid to a dashed line as shown on the graph below.
Which of the following parameters is most likely
to increase as a result of this change?
A. End - diastolic pressure
B. End - systolic volume
C. Stroke volume
D. Ventricular afterload
E. Ventricular preload
------------------------------------------------------------------------------------
II) The volume and pressure tracings for the left
ventricle of a 34 - year - old male are shown below.
Which of the following points corresponds to aortic
valve opening?
A. A
B. B
C. C
D. D
E. E
------------------------------------------------------------------------------------
, III) A 46 - year - old patient is undergoing cardiac catheterization. Initially,
the catheter records periodic pressure changes with a maximum of 27
mmHg and minimum of 2 mmHg. The catheter is advanced further, and
then shows periodic pressure changes with a maximum of 26 mmHg and a
minimum of 10 mmHg.
The initial readings were most likely obtained from which of the following
locations?
A. Right atrium
B. Right ventricle
C. Left ventricle
D. Left atrium
E. Pulmonary artery
------------------------------------------------------------------------------------
IV) Microelectrodes placed into cardiac muscle cells detect a rapid decrease
in cytoplasmic calcium level immediately preceding relaxation.
Which of the following mediates the observed response?
A. Voltage-dependent calcium channels
B. Ryanodine receptors
C. Na+ / Ca+2 exchange mechanism
D. Troponin C
E. Calmodulin
------------------------------------------------------------------------------------
