For 14yrs, I've had panic attacks that present w/ chest pain, feelings of doom/terror & sometimes sweating. How would I recognize a true cardiac event?

Many signs. Weakness, pallor or cyanosis (being blue), poor pulse, poor capillary filling, fluctuations in blood pressure are more likely in mi. Best to treat the panic effectively beforehand, so you won't be faced with that problem. You'll panic over trying to decide if you're having panic. Breathing exercises, meditation, and medication are quite useful. Please see your doctor and counselor for help.
Treat. Agree with dr. Enriquez - have your psychiatrist treat the panic disorders symptoms, which you are describing such as, constant worry that something might happen. You will be able to manage cardiac health more effectively with your primary care doc.