Horsegaitwisely speaking, isn't there a real difference between a gallop and a canter? Something about the order the hooves leave/touch the ground, or the fact of all being off the ground together, or both?
[Esoterica alert] Incidentally, your doctor distinguishes two kinds of heart gallop, one not as welcome as the other. One goes ba-da-BOM, ba-da-BOM, ba-da-BOM and the other is ba-DUM-ba, ba-DUM-ba, ba-DUM-ba. There are first, second, third, and fourth heart sounds, so that's really four-one-TWO, four-one-TWO as opposed to one-TWO-three, one-TWO-three. In adults a four- is a nuisance; a -three is a problem.[/Esoterica]