When I was younger I had an ECG that indicated a shortened QT interval. The tech went pale and went rather quickly to fetch the doctor. The physician got angry at the tech after reading the ECG.

https://en.m.wikipedia.org/wiki/Short_QT_syndrome

I don’t have that, but the tech was visibly alarmed. After reading WAY too much about ECGs (Oh, my fuck is it boring!) I figured out why it’s not a problem, but Short QT Syndrome is something that people simply drop dead from without any warning.

The explanation as to why is simple, but also complex. That’s why you’re getting your concerns dismissed. It might feel abrupt or dismissive, but that’s exactly how you want your doctors to be. Take comfort in what might seem to be a bad bedside manner.