Modify the AD8232 chip configuration to use only LEFT and RIGHT arm in steel leads configuration
You probably don't want connections from RLD to BOTH arm electrodes.  I suggest trying to connect to only ONE of the arm electrodes, through \$360k\Omega \$, and not \$10M\Omega\$.  You want to use one of the arm electrodes as the reference, and you don't want to separate it with large impedance.