If I cast Gust on a Poro and my opponent responds with En Garde (giving +2 health) to the Poro, does Gust fizzle or does something else happen?

Ruling: The Gust resolves without effect and the Poro remains in play.

Nuances:

• When En Garde increases the Poro's health above Gust's damage threshold, Gust still resolves but has no effect rather than being countered or "fizzling" in the traditional sense