I just heard recently about an urban legend type of thing concerning "self CPR", where a person can use coughing to break a coronary event from irregular heartbeat... and it turns out there is *some* basis to it.
How were you feeling when your heart rate spiked?
I'm wearing an event monitor this very minute, and I find that having that instant feedback on heart rate is not conducive to a relaxed heart. So maybe the sneeze (like my yawn in another post) caused a brief vagal response, then you saw the HR on the monitor and it made you nervous, making it harder for your HR to return to normal.
Just a theory.
I hope you get your rhythm issues sorted out.
Your HR was normal before the sneeze then went tachy for a couple mins. after the sneeze? That's never happened to me but that doesn't mean it couldn't happen. Mine has gone tachy just from eating too quickly or too large of bites. There's that whole vagal nerve business running down the esophagus and in the chest area. I imagine a sneeze could trigger a tachy. You can mention it to your doctor but overall you have arrhythmia that needs to be managed somehow. Sneezing is just a little different trigger.