Limp, in My Arms

I was holding Corban today when he had one of his "clamping down" episodes. He started to cry, but was sucking in heavily and struggling to breathe. One minute he was crying and the next minute he dropped his heart rate to 30 bpm and went limp in my arms. Such a scary feeling. His heart rate is normally in the 120s, so 30 is dangerously low. Basically, he was on the way to flat lining.