The good news is that I'm okay (if a wee bit sluggish). The bad news is that the emergency room staff couldn't really tell what happened.
I walk to and from work; it's only a 20 minute walk. It was a little hot here yesterday, but the breeze helped. But by the time I was about 2/3 of the way home, after climbing a flight of stairs at the local train station (cutting through the station is the safest way to cross a 6-lane street on my commute), I noticed that my left arm was going numb and that I was a little lightheaded. When I got home I called the advice nurse to ask what to do, and she advised me to call 911.
The paramedic who conducted the interview was great. I mentioned that I'm MTF and she referred to me as Connie and with femme pronouns thereafter.
I got to go for a ride in an ambulance.
The EKG was good, my blood pressure wasn't too high and my pulse was okay, too. The lightheadedness and numbness in my arm persisted for a while, then eased off. They ruled out stroke and a cardiac event, but it might have been a neurological event. The lightheadedness might be left over from a blood donation last Saturday, which usually leave me a little weak and wobbly.
As an aside, the tech who did the EKG was great, too, saying that some of the sensor stickers had to go under my "left breast." He called my lower-case A-cup booblette a breast.
The ER doctor advised me to follow-up with my GP as soon as possible and have referred me to a cardiologist as well. It's possible I'll be sent to neurologist, too.
This morning I took the bus to work instead of walking. I feel almost like I did on Monday, when I was still a little sluggish after the platelet donation.