Page 4, USMLE, Dr. D. Penney



USMLE-Type Examination Questions - Cardiac Performance:


181.  Within limits, an increase in the end-diastolic volume of the healthy right ventricle will usually
	(A)	decrease the mean ejection pressure of the ventricle
	(B)	increase the stroke work of the ventricle
	(C)	decrease ventricular wall stress
	(D)	decrease the stroke volume of the ventricle
	(E)	increase cardiac muscle Vmax.


184.  Which of the following will cause an increase in left ventricular preload?
	(A)	a decreased end-diastolic volume
	(B)	an increased end-diastolic pressure
	(C)	an increased end-systolic radius
	(D)	an increased stroke volume


185.  Which of the following is a response of the heart to the stimulation of adrenergic sympathetic neurons?
	(A)	it shifts the Starling curve of the heart to the right
	(B)	it increases conduction time
	(C)	it increases cardiac muscle Vmax.
	(D)	it increases the refractory period
	(E)	it decreases rate of rise of ventricular pressure


186.  Which of the following factors is a response of the healthy heart to the stimulation of cardiac parasympathetic neurons?
	(A)	a shift of the Starling curve for the atria to the right
	(B)	a shift of the Starling curve for the ventricles to the left
	(C)	a shift of the Starling curve for the ventricles to the right
	(D)	a speeding of conduction at the AV node
	(E)	a decrease in refractoriness of the AV node


187.  Which of the following statements is most accurate?
	(A)	Ca++ and K+ have synergistic actions on the heart
	(B)	Ca++ has a positive inotropic action on the heart
	(C)	K+ has a positive inotropic action on the heart
	(D)	Ca++ and K+ have a positive inotropic action on the heart and act synergistically
	(E)	the intravenous injection of KCl causes hyperpolarization of cardiac cells


189.  Which of the following does not result from an increase in the inotropicity of the left ventricle?
	(A)	an increase in its ejection fraction
	(B)	an increase in its pre-ejection period/ejection time ratio
	(C)	an increase in the rate of rise of ventricular pressure
	(D)	a decrease in the end-systolic volume of the ventricle
	(E)	an increase in the ventriclešs Vmax


198.  Select the statement that is not correct regarding the heart:
	(A)	an acute increase in the ventricular end-diastolic volume causes an increased ventricular efficiency
	(B)	a major determinant of myocardial oxygen consumption is cardiac afterload
	(C)	a major determinant of myocardial oxygen consumption is heart rate
	(D)	a major determinant of myocardial oxygen consumption is inotropic state
	(E)	an increased inotropic state results in increased contractile efficiency



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