improving my basic ecg circuit

this is my first time posting on here

I have attached a copy of my ecg circuit, i think it is complete and ready to assemble....I have simulated it in multi sims and every things seems ok .


I would like recommendations on any improvements I could make to it ....or if any one can spot any problems I am might have or mistakes I have made

it will be powered from two 9v batteries

my end goal is to have an ecg signal displayed on my oscilloscope .........

any ideas or recommendations are very welcome =]

Have you seen this page?
http://www.cisl.columbia.edu/kinget_group/student_projects/ECG Report/E6001 ECG final report.htm

yea i have seen it very informative