Cardiac Work (I)

Question 1

What 2 things will lead to an increase in work of a ventricle?

Answer 1

1. Increased demand for coronary blood flow

2. Ventricle hypertrophy

Question 2

Which type of increase in cardiac work load leads to the biggest change?

Answer 2

Pressure work is harder for the heart to adjust to rather than volume work.

Question 3

How can long term overstimulation of the heart by NE and Epi lead to adverse heart problems?

Answer 3

1. Chronically decreased cardiac performance (Heart Failure)
2. Chronic excess of NE and Epi (raises HR and contractility)
3. Hypertrophy ( Helps to a point, then makes matters worse)
4. Apoptosis
5. Proliferation of Cardiac connective tissue
6. Cardiac fibers in disarray. (Back to step 1)

Question 4

How does Polycthemia lead to heart failure?

Answer 4

1. Blood is too viscous
2. Increased resistance to flow
3. Heart generates higher arterial pressure
4. Increased work load
5. Heart failure

Question 5

How does Anemia lead to heart failure?

Answer 5

1. Low O2 content of blood
2. Cardiac output must increase (compensation)
3. Increase work load of heart
4. Heart failure