Dry heaving does NOT mean having a heart attack.
Dry heaving is when your body is retching to vomit but no vomit comes out. This can be triggered by smell, stomach problems or something that you find distasteful and makes you retch.
If you do start to have dry heaves, relax and slowly sip a glass of water, also breathe slowly through your nose. If it is a smell that is the trigger to the dry heave, then get away from it or go outside for some fresh air. Too much anxiety or stress can also trigger dry heave. Eating ginger; drinking a hot cup of peppermint or spearmint may also help to settle the dry heaving.
I experience dry heaving when I have to have my teeth xrayed with that piece of plastic they put in your mouth and also if the dentist happens to touch the back of my tongue. Breathing slowly through the nose does help to calm things down.
Medicines that can help to settle down dry heaving are Dramamine and antihistamines such as Antivert and Bonine.
If you are having dry heaving frequently and without any triggers, make an appointment to see your doctor so that you can be thoroughly checked out to find out if there is an underlying health issue causing the dry heaving.
It could, but it could mean allot of other things as well. Are you having the problem, or is it someone else? Could mean that you have a touch of the flu and if you haven't eaten, you wont throw up anything. Sometimes you can gag and fell like you are going to throw up, if something is triggering your gag reflex, for example a sinus infection. I would suggest, that if this is an ongoing problem you see the doctor. Good luck!