I am a heart patient w/ CAD and stent placed about year ago. also have hypothyroidism and asthma. Ihave been having episodes of feeling lightheaded, sweating, and sudden shortness of breath. happens several times a day. doesn t seem to matter whether I am active or just sitting, but last longer if active, but never longer than a few minutes. I am hoping it is not my heart, but afraid it might be. have apt w heart doctor in October. thinking imight need to see him earlier. what do you think?