Sun21November0452PM 12

In a resting patient, which metabolic substrate is likely to contribute most to total energy production in the cardiac muscle?

(Please select 1 option)

Glucose Incorrect answer selected

Lactate

Ketone bodies

Fatty acids This is the correct answer

Amino acids

Explanation

Under normal conditions with adequate oxygen supply, fatty acids provide 50-70% of the total energy demands of the myocardium. Glucose is the metabolic substrate for the remaining 30% of requirements.

The myocardium is able to produce ATP from a variety of substrates - fatty acids, glucose, lactate, pyruvate and even amino acids. The particular source of substrate will depend on the concentration of that particular substrate both in the plasma and myocyte.

Lactate is used under conditions of increased muscular activity during which period lactate concentrations in plasma increase significantly.

Ketone bodies and amino acids may contribute by as much as 10% to total energy production in diabetic ketoacidosis.

Answer Statistics

1

62%

2

1%

3

4%

4

29%

5

6%

Times answered: 249