I call these heart attacks but I'm sure they aren't. My RSD is in the left arm and hand and the first episode felt just like a heart attack is described in the literature. I took everything I have for pain with no effect so went to the hospital figuring it might really be heart. Nitroglycerin helped me as well. Turned out it was not a heart attack and they grow less virulent with each one and less frequent.

It's not something to play around with of course. It seems to be related to stress and with flares for me.

It feels like a thick blanket of pain on my back and surrounding my heart with pain shooting down my arm. Pulse is usually near normal with BP somewhat elevated.