I've had 3 panic attacks, and my cardiologist said I am having a hyperventilation syndrome since my ECG and x rays are normal. Are these diagnostic tests reliable to assume that I didn't have a heart problem?

Could you be experiencing Delayed Stress Syndrome? I lost my oldest son to a car accident in 1994... and then in 1999 I started experiencing panic attacks and started hyperventilating... Also would hide in closets. I was so busy trying to hold my family together for the years between 94 and 99 and get them through their grief, that I didn't go through the grieving process myself. It manifested itself in panic attacks and a rash all over my body that would come and go for 5 years. (I still break out in a small rash when I get upset, never use to do that.) I kept going to doctors and dermatologists and they kept giving me different pills, lotions etc. Nothing worked. Then I ended up seeing a dermatologist who was a Christian man. After he did all the tests and they came back good. He sat me down and asked me, "How is your life?" I started to sob uncontrollably. He suggested I get in touch with someone I could talk to.. He said he could put me on Valium... but I said NO WAY.. He said he was hoping I would say that. By prayer and going through the grief and by patience and some VERY VERY hard days. I don't have the panic attacks anymore.