Hi jdb, did you ever find out the cause and solution? Your symptoms sound similar to what I'm going through currently and it would help me to know. Thanks in advance!
The rare and short-lasting nature of your erratic heart activity sounds like it could be related to some other stimulus, e.g., your reflux.
I suggest you write down the time and physical details each time it happens and discuss your data with your doctor on your next visit.
If the frequency or intensity or duration of the event increase, think about making an early appointment.
Your data will help a doctor diagnose and decide what tests would be the most effective....minimizing cost.