Final answer:
The client with 'pump failure' following a myocardial infarction is experiencing cardiogenic shock, which results from the heart's inability to pump blood effectively.
Step-by-step explanation:
The client who has just experienced an acute myocardial infarction and is diagnosed with "pump failure" is experiencing cardiogenic shock. This condition arises from the heart's inability to maintain cardiac output, most commonly due to a myocardial infarction (heart attack), but it can also be caused by other diseases affecting the heart's function. Treatment involves addressing the primary cause of the heart's failure, which could include repairing any damage to the heart or its vessels.