Dear Dr. Roach: This might be a frivolous question, but is it safe to get a tattoo if I have a pacemaker? I have been told it is not safe, but I don’t think much research has been done. Your answer ...

Some tattoos truly make the heart go pitter-patter. In rats, a graphene “tattoo” stuck to the heart could treat an abnormally sluggish beat. Like a futuristic pacemaker, the device delivered ...