WBR0438: Difference between revisions

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{{WBRQuestion
{{WBRQuestion
|QuestionAuthor={{Rim}}
|QuestionAuthor={{Rim}}, {{AJL}} {{Alison}}
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Physiology
|MainCategory=Physiology
Line 20: Line 20:
|MainCategory=Physiology
|MainCategory=Physiology
|SubCategory=Cardiology
|SubCategory=Cardiology
|Prompt=A 73 year old patient with hypertension presents to the emergency department for dyspnea at rest. Following appropriate evaluation, the patient is diagnosed with heart failure.  The physician explains to the patient that his ventricles are not appropriately relaxing and filling.  Which phase on electrocardiography (ECG) scheme shown below represents ventricular relaxing and filling?
|Prompt=A 73-year-old male with hypertension presents to the emergency room with complaints of shortness of breath at rest. Upon evaluation, you observe that his ventricles are not appropriately relaxing and filling, leading you to diagnose the patient with heart failure.  Which of the following phases on electrocardiography (ECG) scheme (illustrated below) represents ventricular relaxing and filling?


[[Image:Normal ECG.png|400px]]
[[Image:Normal ECG.png|400px]]
|Explanation=The waves on [[ECG]] reflects [[depolarization]] and [[repolarization]] effects; whereas baseline reflects when there is no net depolarization or repolarization, such as in cases of muscular rest or contraction.  On ECG, [[P wave]] reflects [[atrial depolarization]], [[PR segment]] reflects [[AV nodal delay]], [[QRS complex]] reflects [[ventricular depolarization]] and simultaneous [[atrial repolarization]], [[ST segment]] reflects time during which [[ventricular]] contraction is occurring, [[T wave]] reflects [[ventricular repolarization]], and [[TP interval]] reflects the time during which [[ventricles relax]] and refill.
|Explanation=Upon [[ECG]], waves represent [[depolarization]] and [[repolarization]] effects, while baseline represents the absence of net depolarization or repolarization, frequently observed in cases of muscular rest or contraction.  On ECG, [[P wave]]s represent [[atrial depolarization]], [[PR segment]]s represent [[AV nodal delay]], [[QRS complex]]es represent [[ventricular depolarization]] and simultaneous [[atrial repolarization]], [[ST segment]] represents time during which [[ventricular]] contraction is occurring, [[T wave]] represents [[ventricular repolarization]], and [[TP interval]]s represent the time during which ventricles relax and refill.  
Educational Objective:
On ECG, TP interval reflects the time during which ventricles relax and refill.  


Reference:
|EducationalObjectives= On ECG, [[TP interval]]s represent ventricles relaxing and refilling.  
Berne RM. Cardiovascular physiology. Annu. Rev. Physiol. 1981;43:357-358


|AnswerA=PR segment
|References= Berne RM. Cardiovascular physiology. Annu. Rev. Physiol. 1981;43:357-358
|AnswerAExp=PR segment reflects AV nodal delay.
 
|AnswerB=ST segment
|AnswerA=PR segments
|AnswerBExp=ST segment reflects the time during which ventricles contract.
|AnswerAExp=PR segments represent AV nodal delay.
|AnswerC=QRS complex
|AnswerB=ST segments
|AnswerCExp=QRS complex reflects ventricular depolarization and simultaneous atrial repolarization.
|AnswerBExp=ST segments represent ventricle contraction.
|AnswerD=QT interval
|AnswerC=QRS complexes
|AnswerDExp=QT interval reflects total duration of ventricular depolarization and repolarization.
|AnswerCExp=QRS complexes represent ventricular depolarization and simultaneous atrial repolarization.
|AnswerE=TP interval
|AnswerD=QT intervals
|AnswerEExp=TP interval reflects ventricular relaxation and refilling.
|AnswerDExp=QT intervals represent total duration of ventricular depolarization and repolarization.
|AnswerE=TP intervals
|AnswerEExp=TP intervals represent ventricular relaxation and refilling.
|RightAnswer=E
|RightAnswer=E
|WBRKeyword=ECG, electrocardiogram, ventricle, filling, relaxation, wave, repolarization
|WBRKeyword=ECG, electrocardiogram, ventricle, filling, relaxation, wave, repolarization, cardiology, cardiovascular,
|Approved=No
|Approved=Yes
}}
}}

Revision as of 19:02, 22 July 2014
Author [[PageAuthor::Rim Halaby, M.D. [1], Alison Leibowitz [2] (Reviewed by Alison Leibowitz)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Physiology
Sub Category SubCategory::Cardiology
Prompt [[Prompt::A 73-year-old male with hypertension presents to the emergency room with complaints of shortness of breath at rest. Upon evaluation, you observe that his ventricles are not appropriately relaxing and filling, leading you to diagnose the patient with heart failure. Which of the following phases on electrocardiography (ECG) scheme (illustrated below) represents ventricular relaxing and filling?

]]

Answer A AnswerA::PR segments
Answer A Explanation AnswerAExp::PR segments represent AV nodal delay.
Answer B AnswerB::ST segments
Answer B Explanation AnswerBExp::ST segments represent ventricle contraction.
Answer C AnswerC::QRS complexes
Answer C Explanation AnswerCExp::QRS complexes represent ventricular depolarization and simultaneous atrial repolarization.
Answer D AnswerD::QT intervals
Answer D Explanation AnswerDExp::QT intervals represent total duration of ventricular depolarization and repolarization.
Answer E AnswerE::TP intervals
Answer E Explanation AnswerEExp::TP intervals represent ventricular relaxation and refilling.
Right Answer RightAnswer::E
Explanation [[Explanation::Upon ECG, waves represent depolarization and repolarization effects, while baseline represents the absence of net depolarization or repolarization, frequently observed in cases of muscular rest or contraction. On ECG, P waves represent atrial depolarization, PR segments represent AV nodal delay, QRS complexes represent ventricular depolarization and simultaneous atrial repolarization, ST segment represents time during which ventricular contraction is occurring, T wave represents ventricular repolarization, and TP intervals represent the time during which ventricles relax and refill.

Educational Objective: On ECG, TP intervals represent ventricles relaxing and refilling.
References: Berne RM. Cardiovascular physiology. Annu. Rev. Physiol. 1981;43:357-358]]

Approved Approved::Yes
Keyword WBRKeyword::ECG, WBRKeyword::electrocardiogram, WBRKeyword::ventricle, WBRKeyword::filling, WBRKeyword::relaxation, WBRKeyword::wave, WBRKeyword::repolarization, WBRKeyword::cardiology, WBRKeyword::cardiovascular
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