How to choose a Instrumentation Amplifier
I would redirect you to consider the ADS1298  which has the Right leg drive (RLD)and everything else you need for ADC.

http://www.ti.com/lit/sg/slyt416/slyt416.pdf


  The ADS1294/6/8 are a family of multichannel, simultaneous sampling,
  24-bit, delta-sigma (ΔΣ) analog-to-digital converters (ADCs) with a built-in programmable gain amplifier (PGA), internal reference and onboard oscillator. The ADS1294/6/8 incorporate all of the features that are commonly required in medical electrocardiogram (ECG) and electroencephalogram (EEG) applications