mohsen abbasnezhad department of cardiology, tabriz university of medical sciences, tabriz, ir iran hassan soleimanpour cardiovascular research center, tabriz university of medical sciences, tabriz, ir iran; cardiovascular research center, tabriz university of medical sciences, tabriz, ir iran. tel: +98-9141164134, fax: +98-4113352078 mohamadreza sasaie students’ research committee, tabriz university of medical sciences, tabriz, ir iran samad ej golzari medical philosophy and history research center, tabriz university of medical sciences, tabriz, ir iran saeid safari department of anesthesiology and critical care, iran university of medical sciences, tehran, ir iran maryam soleimanpour gastroenterology research center, tabriz university of medical sciences, tabriz, ir iran