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Figure 12.5 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:
- Z might represent conditions in the failing ventricle at rest.
- Y might represent resting conditions in the ventricle in hypertension prior to failure.
- Y, rather than point V, might represent conditions in the ventricle after administration of a beta adrenoceptor agonist drug.
- V might represent conditions in a patient with aortic valve stenosis prior to failure.
- W might represent the conditions in hypovolaemic circulatory failure.
Medicine
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.
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