I have had a similar experience. I am 59 years old. While in college, I was diagnosed as having PVC's after visiting the university health center complaining about an irregular heartbeat. The irregular heartbeat diminished over the years, and I essentially forgot about it.
Recently, I had an epidural steroid injection. Two - three days after the injection, I started having irregular heartbeats similar to those I experienced as a college student. These disappeared after 3 days. I then had a second injection. Once again, am experiencing the irregular heartbeats, and it has been 8 days since the 2nd injection. They are more pronounced this time and have not yet gone away. This is a frustrating experience.
I'm not sure about any correlation, but I would for sure discuss the symptoms with the doctor that subject procedure and gave you the steroid shots. Steroids are strong medication and can cause many side effect, I believe.