Rudd,
If the heart was almost completely gone, I don't think there's much to worry about, even without an exit wound. I've had limited experience with my muzzleloader but the doe I shot last year was at 30 yds. with 100 gr. Pyrodex pellets and 295-gr. copperclad hollowpoint Powerbelt. She dropped like a rock and I found the bullet in three main pieces and some fragments. The shoulder was shattered. Given the expansion and shock delivered by this bullet/powder combination, I think it would be unusal to actually have a passthrough. Just my two cents.
Threebeards