arrhythmias... (why are subject lines so restricted in length?)

Anyhow, my wife (age 60, occasional jogger, 15-20 miles per week max) has recently developed episodes of premature atrial contractions and sometimes full AF.

We've come to realise that these seem to be aggravated by her making any attempt to run further or faster. If she backs off the running they go away, if she starts trying push, even slightly, they start to come back again. It's perhaps become more of an issue for her as she's now retired and had hoped to do more running but now finds that even with medication (Flecanide), she really can't push herself faster than a pretty modest jog without sparking off more ectopics. Once she gets them, it takes a few days of no running (and flecanide) before they stop. This is just frustrating for her.

By way of medical history, she's enjoyed good health all her life but has never been able to run fast. 5K pb is over 30 minutes. Just over two years ago, she started developing odd chest aches, radiating to her right shoulder, on about a monthly basis. The pain would last about 24 hours, and then, 24-48 hours later, she would flip into full AF. Each time this would revert to normal rhythm within 24 hours. After about a year of this and a bunch of inconclusive tests, after a more strenuous run followed by a bout of food poisoning, she developed full blown pericarditis and ended up on mega strong IV antibiotics for 3 weeks.

This cleared things up, the odd chest pain have never recurred and we though we were out of the woods until she started trying to improve her running recently when the PACs and short bouts of AF recurred.

I doubt anyone else has had anything quite like this but if I was wondering if there was anyone else out there who had episodic arrhythmias induced by exercise, and if so, had they found any solution. We've tried using an HRM to run to a tight HR limit but that really didn't seem to help.