Question

Heart disease may limit exercise tolerance by 

A. Reducing the patient’s maximal cardiac output. 

B. Increasing the left ventricular ejection fraction. 

C. Depriving cardiac muscle of an adequate blood supply. 

D. Decreasing heart rate through increased vagal tone. 

E. Changing the relationship between cardiac work and fibre length.

Answer 1

A. True This is the main mechanism limiting exercise. 

B. False It decreases ejection fraction and hence stroke volume and cardiac output. 

C. True This causes temporary (angina) and potentially permanent (myocardial infarction) dysfunction. 

D. False It may decrease heart rate by blocking impulses from the sinoatrial node to the ventricles. 

E. True It decreases work done at a given fibre length on the left ventricular function curve.