Yep that heart has some wonderous effects in the deer when hit by a screaming projectile. I have seen the deer run like I missed it, only to fall 75 yds or so. I have seen a good buck jump straight into the air like a bucking bronc, and run for 100 yds, and that heart was hamburger. But the one that puzzles me mostly is a little doe I shot several years back, with a .270 win, 130 grain Ballistic Tip, poi was just behind the knucle of her shoulder, and she jumped straight up into the air like she was bouncing off a trampoline, she ran for 1/4 mile where I found her, (blood trail) 3 hrs later eating brush..
I shot her again in the same area only on the other side, only for her to again jump straight into the air like shot out of a cannon, only to land dead, her heart was hamburger, both bullets passed through her chest, but I think only the last hit her heart well.