When a client with a possible past history of myocardial infarction has an electrocardiogram (ECG) prescribed and asks the nurse the purpose of the ECG, which response by the nurse is accurate?
a. "This test will look for heart valve problems."
b. "This test will show how well your heart is pumping."
c. "The ECG will tell us how much exercise your heart can tolerate."
d. "The ECG will show if there has been damage to the heart muscle."