genejockey 

Last night I did a workout on Wahoo's Systm, which I signed up for just to try a longer plan. It was provocatively titled "A Very Dark Place", and consisted of 5 blocks of 4 minutes, between 100 and 115% of FTP, with two of the segments also including 10 second sprints. It was hard, but not as bad as all that.

Then, when I went to bed about 5 hours later, as I lay there I felt an odd kind of 'flutter' in my chest. I checked my pulse at the wrist, and it was... irregular. Not too fast or to slow. More like syncopated, averaging around 50-60 bpm, but at irregular intervals, like beat - pause - beat beat - beat - beat - beat beat - beat - beat - pause - beat, beat. Like that. No other symptoms, but of course my anxiety shot up. I couldn't get back to sleep for 3 hours, during which every time I checked, my pulse was steady. I spent a while looking it up online, remembering that I had been diagnosed a few years back with a murmur involving my mitral valve, and that can apparently cause mild occasional arrythmia.

Contacted my PCP this morning, who basically said, Don't Panic, come by for an EKG sometime this week. Maybe don't ride today, and go at reduced effort tomorrow. So, now I'm feeling betrayed by my body, and wondering what it all means.