Speaking heart shots, I hit a fallow deer spiker a little low through the chest cavity with a 150g SST out of my 270 Win at 70 odd yards. Bullet hit the fore-leg bone before travelling through the chest.
It ran about 50y before falling down. It was still sitting upright looking at me when I head shot it to finish. I'm convinced it was the broken leg as much as anything that caused it to fall.
When dressing the animal the bottom of the chest was blown apart and the heart and lungs were OUTSIDE the deer and in a mess (ie shredded), yet it still ran that 50y and lived another 60 seconds until I got in position to head shoot it from around 40y.
