Can A Heart Attack Be Prevented?

Hello. My mother went to primary care doctor after having chest & and arm pain. The Dr said it was a possible heart attack and referred her to a cardiologist. They also took a blood test to check her enzymes. The cardiologist still hasn t contacted her in 2 days. Her primary Dr called her today and told her that it was a heart attack but didn t prescribe her any medication or refer her to the ER where she can have further tests done. She s saying that her primary Dr. said that she could have another one within 24-72 hours. Why didn t her primary Dr. tell her to go into the ER or prescribe medication to lower the risk of a second one? Is there a chance of her having a second one within the next couple days?