What Lies says applies IMO to a dog in heat - when they may be in a little different world. It's been a couple of years but when I was training Kayla in those first two years, the first heat, she went through a lost my mind stage breifly. We just worked on basics-what she already knew. It simply was not a good time to try to teach new things. It's a good time to reinforce those skills you've already taught. Just make sure to end any sessions on a good note, so if she checks out go back to something she'll do successfully and then end the session.
A year later, we were getting ready for our first fling in the ring for Rally and Kayla went into heat four weeks prior which meant no classes just before going into the ring so I bought a set of the Rally signs and equipment and we worked at the nearby school yard. I needed her remembering when she saw a course with those sighs, we were going to work. Didn't even want to think what four weeks without training would lead to that first go around.
Kayla (RIP) 02/12/05-09/22/14