Okay, so the trick is to look up when he's coming at you from the sides. If you slash, your sword will knock him upwards, into the electricity. Arrows can also work well. As soon as he's being electrocuted, run in and hack away at the heart panel like mad, while you can. Rinse and repeat.
Ha! Got him last night. But like I said, I couldn't tell what combination worked. But I did notice that he appeared to be "stunned" when he got thrown into the electric pillars. Thanks for explaining! (rinse and repeat




