How to use "seizure" in a sentence

In two seconds, it was in his bloodstream, and the first seizure hit his heart.

Although he was struggling to cast off the seizure of claustrophobia that had gripped him, was trying to pretend that the organic-looking ceiling wasn't pressing low over his head and that only open sky hung above him instead of thousands of tons of concrete and steel rock, his own panic attack concerned him less than what was happening beyond the viewport.