On the left we have the heart pattern in Learn to Tat by Janette Baker. It's done in size 10 variegated Aunt Lydia's crochet thread with cream Lizbeth in size 10. On the right is a pattern from The Gentle Art of Tatted Hearts
(Rizzo). I used size 10 Lizbeth in Lollipop and cream for this one. The pattern is beautiful, but the notations are hard to follow in this book. They are equally hard to follow in the other book of hers I purchased, The Gentle Art of Tatting.
Here's the heart from the cover of that book.
It is also in Aunt Lydia's crochet thread size 10. And the point didn't come out right, so I improvised. I like the result, but I wish the bottom were more pointed. I will be trying it again.