"Misfiring" heartbeat. Possibly an incomplete BBB (Bundle Branch Block, IBBB), RBBB, right...or LBBB, left. Very wise to have it checked out, of course. A standard 12-lead resting EKG might reveal something of that sort. A stress test (either standard or Thalium) would be even better. I myself have an ILBB, but a referral to a cardiologist in your presentation would indeed be a good idea. I've been a runner and bicyclist for a good many years, so "ahead of the curve", as it were, but we all only last so long. Good luck following that up, Rashida. Cheers, -Justin