My experience after 48 years of bow and gun hunting--a heart shot deer will bleed ! Period- either from the sides or through the mouth, BUT they will bleed ! especially a deer with 2 exit holes ! which most bullets will do when hitting chest area !

Upon reading this post brings me to my recent deer loss endeavor. I shot a really nice big fat doe this past firearms season here in Illinois. I shoot a .460 Smith pistol with 225grn Horn FlexTip at 1935fps. I shot her about 15mins from legal end of the day at 80yds. Saw her hunch up and run into the timber. Was amazed she didn't just drop. I aimed about 8 inches up from bottom while on shooting sticks. Went to impact spot. Found hair and large pieces of lung matter on the winter wheat. Figured good blood trail. Nope!!! Ran out within 10 yds. Left and brought back-up in the AM. Barely found blood and found where she fell down the hill and went maybe another 30yds. 70yds total from impact site. 'Yotes found her first. Peeled her inside out like a banana. Nothing rest of season. So I feel your pain when you don't find blood and KNOW it was a good hit.

I learned a different technique
 

I learned from my first gun deer to drop it in the spot I shot it. I kept doing in the same way after that. One gun shot; instant dropping. One deer shot; deer down.

Got into archery again after some years away. Thought I needed to learn the blood drop searching.
Shot my first deer with a bow. Took out my compass, and took a directional reading on the last spot I saw the deer. First search was going to be right on the reading. Assumed it only went fifty yards.
Found the deer fifty or so yards away right in some thick cover; right on the last reading of the compass.

Had learned something gun hunting; learned to look for a whole deer and not some small blood drop.