I am so sorry that I forgot to update.
So the week after my appointment with the cardiologist, I was scheduled for my echocardiogram. I went into the doctor's office, up to where they do those tests, and they used the ultrasound machine to try to get a picture of my heart and see what it was doing. Normally they have you lie on a bed – well, a table, really – when they use the machine because it makes it easier somehow (something to do with moving the heart closer to the outside of your chest I think). But their table was notably small – I know that all large number of people who come in for heart tests have got to be overweight, so I'm surprised that the table was not appreciably bigger – so I simply sat in my wheelchair as they did their best with their handheld ultrasound. I was very concerned that they weren't getting the right kinds of readings, and they told me that if the test did not show what they needed to see that I might have to go to the hospital for a procedure where they would put me to sleep and get a sensor directly onto my heart. I may be misremembering details.
Since I figured I would be going into the hospital for this procedure, I tried to skip out of my doctors appointment for the next week. But they said no, to go ahead and keep that appointment and meet with the cardiologist. I was kind of miffed, really, because I didn't want to pay the doctor forty dollars more just to have him tell me to go to the hospital. But I did what they said.
When I got to the doctor's office (this was last week now), I discovered that he was held up at the hospital and would be about an hour late. They said that I could wait or that I could speak with the Nurse Practitioner who worked with him. I know from experience that the Nurse Practitioners are essentially full-fledged doctors who wanted to make sure that their emphasis was on patient care – the "doctor" I see normally is actually a Nurse Practitioner – so I went ahead up to talk to her. I still ended up waiting about an hour.
Anyhow, enough narrative. She told me that the results of my echocardiogram were fine, that my heart was beating the way it was supposed to and looked the way it was supposed to. No worries, no problems. She told me I should make an effort to exercise in order to keep it working well and said that I had many years ahead of me. That was encouraging!
So all is well :-)