Is it possible to measure the voltage produced in heart
It is definitely possible to measure the voltage using lab equipment, and a little bit of help.

You'll want to use some type of amplifier, ideally a precision, instrumentation amplifier - these are designed with very good Common Mode Rejection (CMRR) and gain. 

Once you've set up an instrumentation amplifier, all you'll need is to connect the output to your oscilloscope, so that you can see the waveform.

Here is an example circuit (taken from here) - this site also has a lot of good, further reading.



Please, if you intend to make such a device, be very careful! Connecting the human body to any electrical device can be dangerous, and appropriate precautions should be observed!