Watch the Open Options online guitar lesson by Brad Carlton from Chord Studies: Open String Chords Vol. 2
This progression is a nice shuffle in the key of E with a descending bass line on the fifth string. Our first chord is the E9 with no 3rd. For the A/E chord, you've got to finger that without disturbing the high E string, which we want to ring. We get a break from the tension and hand contortion with a straight ahead E7. You could try playing this without the low E ringing to highlight the descending bassline on the A string.