hi and welcome well this old patient with heart disease and no info what so ever , she previously had heart attacks or minor heart pains...what are the findings of her ECHO and what is her EF( EJECTION FRACTION) of the heart. patient stented might not necessarily have good heart functions back to level if the heart attack had already damaged her heart. with low EF she might be taking digoxin which can cause nausea and vomiting and could be the cause. does she has normal heart rhythm or any palpitation can cause nausea and light headedness. example SVT or AF. re angiography might have been done keeping in view of all these things by the concerned team.. a simple gastro eneteritis / diarrhea may not occur necessarily ..only vomiting can also manifest.. so this gastic problem can cause chest pain because heart races in such circumstances , and if there is residual ischemia at a small vessel level.... then angiography can not pick it up.... THALLIUM SCAN can be a better option ..to rule out ischemia and also anemia( less haemoglobin ) under stress can cause chest pain ...and one important thing is as i said fast palpitations.... so i think you should consult back to your concerned cardiologist and better to get her labs done before his visit... which recommended can be full blood count .... to see anemia thyroid functions .. for palpitations renal functions and liver functions thanks and take care