I have done it before - it is pretty easy.
For MTC:
Have the text and the heart on 2 separate layers. With
both the text and the writing visible, do the engraving first with the engraving tool - set the offset to 0 and the overcut to 0 as well if that is possible. Now, without moving to a different origin, change the engraving tool out for a blade holder. This will be the tricky part since you can't really do a test cut to check your settings. If you have cut the material before, you should have an idea of the blade height, force, etc. Go back to your program,
hide the text layer so just the heart layer is showing. Add the blade offset back as well as the overcut. Cut out the heart. and that's it.
The reason you have both the heart and the text visible when engraving is because when cutting knife point, the blade starts at the bottom right of your image (portrait view). If you make the heart invisible, then there is a new bottom right position. Since you will be cutting the heart out eventually, it does not matter if you engrave in that area first.
For SignCut:
Pretty much the same as above, but you don't have to engrave the heart too - just make sure that you have the optimized/whole area button toggled (
learn/signcut_manual/lessons/The_Important_Icons_in_SignCut.html). Engrave just the text with the engraving tool (no blade offset or overcut), switch so the heart is visible and text is invisible and then cut out the heart with the blade.