Hello Sometimes high blood pressure develops fullness in epigastrium region and patient feels pain and fullness in abdomen . In your husband case as doctor told that there is thick blood means lipid profile are elevated . This is known as high cholesterol level and this is dangerous , if untreated . But one thing is very nice that E K G is normal , so at present need not to worry. However this is concerning . Consult a Cardiologist and get his opinion . When such patient visit in my clinic I advise them change their life style and also change dietary habit . Regular exercise either walking ( morning or evening for 1/2 hour ) . Avoid fried , greasy , oily food , also avoid alcohol , smoking. In my opinion consult a cardiologist and get his opinion. Good luck.