A 60-year-old man is admitted to the coronary care unit with a large anterior wall myocardial infarction. On his second hospital day he begins to complain of the sudden onset of numbness in his right foot and an inability to move his right foot. On physical examination, the right femoral, popliteal, and pedal pulses are no longer palpable. Vascular consultation is obtained. Diagnosis of acute arterial embolus is made. Which of the following statements concerning this condition is true?