Wow, in my studies in school and my degree in the field, I have never heard of that. If I had told a professor someone had a RHR of 140 he'd ask what type of animal. YIKES. Yeah, get it checked or re-check the count. Some people do screw up, but its hard.
Yeah, at the BPM you'd be dead.
If I woke up in bed and did a RHR and got that, i'd be headed to the DR. Even at 100 bpm.
I may also suggest an Exercise Physiologist who specializes in the heart area. There are many out there, and can be MUCH better at helping than your plain Dr.