Question

Figure shows left ventricular (LV) function curves of the Frank–Starling type. If point X on curve B represents the conditions in the normal heart at rest then point: 

a. Z might represent conditions in the failing ventricle at rest. 

b. Y might represent resting conditions in the ventricle in hypertension prior to failure. 

c. Y, rather than point V, might represent conditions in the ventricle after administration of a beta adrenoceptor agonist drug. 

d. V might represent conditions in a patient with aortic valve stenosis prior to failure. 

e. W might represent the conditions in hypovolaemic circulatory failure.

Answer 1

a. True Stroke work is subnormal; end-diastolic pressure increased. 

b. False In early hypertension the left ventricle hypertrophies; stroke work is greater than normal at a given filling pressure (point V on curve A).

c. False Such a drug, e.g. isoproterenol (isoprenaline), mimics sympathetic stimulation and moves the ventricular curve upwards and to the left (to a point below V on curve A). 

d. True Stroke work is considerably increased, end-diastolic pressure little changed. 

e. True Ventricular function is normal but filling of the heart is inadequate.